TRANSCRIBER'S NOTE
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to Tome (no italic), for consistency.
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For consistency, instances of 'fireworks' and 'fire works' have
been changed to the predominant form 'fire-works'.
Obvious typographical errors and punctuation errors have been
corrected after careful comparison with other occurrences within
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A
SYSTEM OF PYROTECHNY,
COMPREHENDING THE THEORY AND PRACTICE, WITH THE
APPLICATION OF CHEMISTRY;
DESIGNED FOR EXHIBITION AND FOR WAR.
_IN FOUR PARTS_:
CONTAINING AN ACCOUNT OF THE SUBSTANCES USED IN FIRE-WORKS;
THE INSTRUMENTS, UTENSILS, AND MANIPULATIONS; FIRE-WORKS
FOR EXHIBITION; AND MILITARY PYROTECHNY.
ADAPTED TO THE
MILITARY AND NAVAL OFFICER, THE MAN OF SCIENCE
AND ARTIFICER.
_BY JAMES CUTBUSH, A. S. U. S. A._
LATE ACTING PROFESSOR OF CHEMISTRY AND MINERALOGY, IN THE UNITED
STATES' MILITARY ACADEMY--MEMBER OF THE AMERICAN PHILOSOPHICAL
SOCIETY--CORRESPONDING MEMBER OF THE COLUMBIAN INSTITUTE--MEMBER
OF THE LINNÆAN AND AGRICULTURAL SOCIETIES OF PHILADELPHIA--LATE
PRESIDENT OF THE COLUMBIAN CHEMICAL SOCIETY, AND VICE-PRESIDENT OF
THE SOCIETY FOR THE PROMOTION OF A RATIONAL SYSTEM OF EDUCATION,
&C. &C. &C.
PHILADELPHIA:
PUBLISHED BY CLARA F. CUTBUSH.
1825.
EASTERN DISTRICT OF PENNSYLVANIA, to wit:
BE IT REMEMBERED, that on the ninth day of February, in the
forty-ninth year of the independence of the United States of America,
A. D. 1825, CLARA F. CUTBUSH, of the said district, hath deposited
in this office the title of a book, the right whereof she claims as
proprietor, in the words following, to wit:
_A System of Pyrotechny, comprehending the Theory and Practice,
with the application of Chemistry; designed for Exhibition and
for War. In four parts: containing an account of the Substances
used in Fire-Works; the Instruments, Utensils, and Manipulations;
Fire-Works for Exhibition; and Military Pyrotechny. Adapted to the
Military and Naval Officer, the Man of Science, and Artificer. By
James Cutbush, A. S. U. S. A. late Acting Professor of Chemistry
and Mineralogy in the United States' Military Academy--Member
of the American Philosophical Society--Corresponding Member of
the Columbian Institute--Member of the Linnæan and Agricultural
Societies of Philadelphia--late President of the Columbian Chemical
Society, and Vice-President of the Society for the Promotion of a
Rational System of Education, &c. &c. &c._
In conformity to the act of the congress of the United States,
intituled "An act for the encouragement of learning, by securing the
copies of maps, charts, and books, to the authors and proprietors of
such copies, during the times therein mentioned."--And also to the
act, entitled, "An act supplementary to an act, entitled, "An act
for the encouragement of learning, by securing the copies of maps,
charts, and books, to the authors and proprietors of such copies
during the times therein mentioned," and extending the benefits
thereof to the arts of designing, engraving, and etching historical
and other prints."
D. CALDWELL,
_Clerk of the Eastern District of Pennsylvania_.
_To the Corps of Cadets, of the United States' Military Academy, West
Point_;
GENTLEMEN,
To you, a scientific and distinguished Corps, this work on Pyrotechny
is respectfully dedicated. Your liberal subscription first encouraged
me to undertake its publication; for which, accept my grateful thanks.
CLARA F. CUTBUSH.
ADVERTISEMENT.
In submitting the present work to the public, it may be proper to
state some of the difficulties, under which it has been published,
and to bespeak an indulgent allowance for any imperfections, which
may be observed in the style or arrangement. As a posthumous work, it
has been deprived of those final improvements and emendations, which
are generally made by Authors, while their works are in progress
of publication. While, however, the work has laboured under these
disadvantages, the publisher has felt it her duty to make every
arrangement, to supply, as far as possible, the want of the author's
personal superintendence of the publication. This course was due to
the scientific reputation of her late husband, as well as to the
numerous and generous patrons of the work.
_Philadelphia, April, 1825._
TABLE OF CONTENTS.
PART I.
CHAPTER I.
Page.
Pyrotechny in General, 1
Sec. i. Definition of Pyrotechny, ib.
ii. General Theory of Pyrotechny, ib.
iii. Remarks on the Nature of Particular Compositions, 9
iv. Of Illuminations, 23
v. Of some of the Feats or Performances by Fire, 26
CHAPTER II.
Of the Substances used in the Formation of Fire-works, 48
Sec. i. Of Nitrate of Potassa, or Saltpetre, ib.
ii. Of Nitrate of Soda, 73
iii. Of Chlorate of Potassa, 74
iv. Of Sulphur, 78
v. Of Phosphorus, 84
vi. Of Charcoal, 87
vii. Of Gunpowder, 97
viii. Of Lampblack, 144
ix. Of Soot, 145
x. Of Turpentine, Rosin, and Pitch, 146
xi. Of Common Coal, or Pitcoal, 149
xii. Of Naphtha, Petroleum, and Asphaltum, 153
xiii. Of Oil of Spike, 156
xiv. Of Amber, ib.
xv. Of Camphor, 157
xvi. Of Gum Benzoin, and Benzoic Acid, 161
xvii. Of Storax Calamite, 162
xviii. Of Essential Oils, 163
xix. Of Mastich, ib.
xx. Of Copal, 164
xxi. Of Myrrh, ib.
xxii. Of Sugar, 165
xxiii. Of Sal Prunelle, 167
xxiv. Of Alcohol, 168
xxv. Of Fulminating Mercury, 171
xxvi. Of Fulminating Silver, 173
xxvii. Of Fulminating Gold, 175
xxviii. Of Fulminating Platinum, 176
xxix. Of Detonating Powder from Indigo, 177
xxx. Of the Fulminating Compound, called Iodide of Azote, ib.
xxxi. Of Detonating Oil, or Chloride of Azote, 179
xxxii. Of Pyrophorus, 180
xxxiii. Of Sal Ammoniac, 184
xxxiv. Of Corrosive Sublimate, 186
xxxv. Of Orpiment, 187
xxxvi. Of Antimony, 188
xxxvii. Of Carbonate of Potassa, 189
xxxviii. Of Wood Ashes, 192
xxxix. Of Clay, 193
xl. Of Quicklime, 194
xli. Of Lapis Calaminaris, 195
xlii. Of Zinc, 196
xliii. Of Brass, 197
xliv. Of Bronze, 198
xlv. Of Mosaic Gold, 200
xlvi. Of Iron and Steel, 201
xlvii. Of Glass, 210
xlviii. Of Glue and Isinglass, 214
xlix. Of Wood, 216
l. Of Linseed Oil, 218
li. Of Gum Arabic and Gum Tragacanth, 219
lii. Of Cotton, ib.
liii. Of Bone and Ivory, 220
liv. Of Galbanum, 221
lv. Of Tow and Hemp, 222
lvi. Of Blue Vitriol, ib.
lvii. Of Nitrate of Copper, 223
lviii. Of Strontia, 224
lix. Of Boracic Acid, 226
PART II.
Instruments, Tools, and Utensils, 228
CHAPTER I.
Of the Laboratory, 228
Sec. i. Of Laboratory Tools and Utensils, ib.
ii. Of Mandrils and Cylinders for forming Cartridges
and Cases, 230
iii. Of Rammers, Charges, and Mallets, 231
iv. Of Utensils necessary for constructing Signal
Rockets, 232
v. Of the rolling or plane Board, 233
vi. Of the Driver for Charging large Rockets, 233
vii. Of Mortars and Pestles, ib.
viii. Of the Choaker or Strangler, ib.
ix. Of the Table and Sack for mealing Gunpowder, 234
x. Of Sieves, ib.
xi. Of the Paper Press, ib.
CHAPTER II.
Preliminary operations in the preparation of fire-works, and
observations on the preservation of Gunpowder, and sundry
manipulations, 235
Sec. i. Of the Workshop, ib.
ii. Of the Magazine, ib.
iii. Of the Driving or Ramming of Sky-rockets, 236
iv. Of the Boring of Rockets, 238
v. Of the Preservation of Steel or Iron filings, 239
vi. Of the Making of Wheels and other Works
incombustible, 240
vii. Of the Formation of Rocket and other Cases, 243
viii. Of Tourbillon cases, 245
ix. Of Balloon Cases, or Paper Shells, ib.
x. Of Cases for Illumination Port-Fires, 246
xi. Of Cases and Moulds for Common Port-Fires, 247
xii. Of Pasteboard, and its Uses, 249
xiii. Of the Pulverization of Substances, 253
xiv. Of Mixtures, ib.
PART III.
Fire-Works in General, 255
CHAPTER I.
Observations on Fire-works, 255
CHAPTER II.
Fire-works for Theatrical Purposes, 262
Sec. i. Of Puffs, or Bouffées, ib.
ii. Of Eruptions, 263
iii. Of the Flames, 264
iv. Of the Fire-rain, ib.
v. Of other Compositions for Fire-rain in Chinese Fire, 265
vi. Of Thunderbolts, (_Foudres_), ib.
vii. Of Dragons and other Monsters, 266
viii. Of Lightning, 267
ix. Of the Artifice of Destruction, ib.
x. Of the Spur-Fire, ib.
xi. Of the Coloured Flame of Alcohol, 269
xii. Of Red Fire, 270
CHAPTER III.
Of Portable Fire-works, 271
Sec. i. Of Exhibitions on Tables, ib.
ii. Of Table Rockets, 272
iii. Of the Transparent Illuminated Table Star, 273
iv. Of Detonating Works, ib.
CHAPTER IV.
Of Scented Fire-works, 283
Sec. i. Of Pastilles, 286
ii. Of Vases of Scent, 288
iii. Remarks on Spontaneous Accension, ib.
iv. Of Torches, and Odoriferous Flambeaux, 289
v. Remarks concerning Odoriferous and Fetid Fire, 290
CHAPTER V.
Of Matches, Leaders, and Touch Paper, 292
CHAPTER VI.
Of the Furniture, or Decorations for Fire-works, 298
Sec. i. Of Serpents, ib.
ii. Of Crackers, 300
iii. Of Single Reports, 301
iv. Of Serpent Stars, ib.
v. Of Whirling Serpents, 302
vi. Of Chinese Flyers, 303
vii. Of Simple Stars, ib.
viii. Of Rolled Stars, 304
ix. Of Cracking Stars, ib.
x. Of Sundry Compositions for Stars, designed for
Various Purposes, ib.
xi. Of the Fire-rain, (filamentous), 309
xii. Of Sparks, ib.
xiii. Of Gold-rain, 310
xiv. Of Rains in General, for Sky-Rockets, &c. 311
xv. Of Rain-Falls and Stars, double and single, ib.
xvi. Of substances which show in Sparks, 312
xvii. Of Italian Roses, or Fixed Stars, 313
xviii. Of Lances of Illumination, white, blue and yellow, 314
xix. Of Slow White-flame Lances, 315
xx. Of Lights, ib.
xxi. Of Lances for Petards, 318
xxii. Of Lances for Service, ib.
xxiii. Of Marrons, ib.
xxiv. Of Shining Marrons, 320
xxv. Of Saucissons, 321
xxvi. Of Fire-Pumps, 322
xxvii. Of the Volcano of Lemery, 323
xxviii. Of the Blue and Green Match for Cyphers, Devices
and Decorations, 324
xxix. Of the Purple or Violet Match, 325
xxx. Of Meteors, ib.
CHAPTER VII.
Of Rockets and their Appendages, 326
Sec. i. Of the Caliber and Proportion of Rockets, ib.
ii. Of the Composition of Sky-Rockets, and Observations
on its Preparation, and on other Subjects
respecting rockets, 329
iii. Of the Heading of Rockets, 334
iv. Of the Decorations for Rockets, and the Manner
of filling their Heads, 335
v. Of the Dimensions, and Poise of Rocket-Sticks, 336
vi. Of the Mode of Discharging Rockets, 337
vii. Of the Appendages, and Combinations of Rockets, 340
viii. Of Swarmers or Small Rockets, 343
ix. Of Scrolls for Sky-Rockets, and of Strung, Tailed,
Drove, and Rolling Stars, 344
x. Of Line-Rockets and their Decorations, 345
xi. Of Signal Sky-Rockets, 347
CHAPTER VIII.
Of Sundry Fire-works, denominated Air-works, 347
Sec. i. Of the Composition, and Mode of Forming large
and small Gerbes, 348
ii. Of Paper Mortars, 349
iii. Of Mortars to throw Aigrettes, &c. 350
iv. Of Making Balloon Fuses, 357
v. Of the Mosaic and Common Tourbillon, 358
vi. Of Mortars for throwing Aigrettes, and the
Manner of Loading and Firing them, 363
vii. Of Making, Loading, and Firing Pots des Brins, 364
viii. Remarks respecting Fire Pots, 365
CHAPTER IX.
Of Particular Compositions, 367
Sec. i. Of Fire-Jets, or Fire-Spouts, ib.
ii. Of Priming and Whitening Cases, and Remarks
concerning Spunk and Touch Paper, 370
iii. Of Chinese Fire, 371
iv. Of Bengal Lights, 377
v. Of Roman Candles, 380
vi. Of Mosaic Simples, 381
vii. Of Mosaic Tourbillons, 382
viii. Of Hydrogen Gas in Fire-works, 383
CHAPTER X.
Of the Manner of fixing and arranging Fire-works in General
for Exhibition, 387
Sec. i. Of the Composition of Wheel-Cases, Standing
and Fixed, 388
ii. Of Single, Vertical, Horizontal, Spiral, and
other Wheels, 391
iii. Of Revolving Suns, 395
iv. Of Fixed Suns, 397
v. Of Fixed Suns with Transparent Faces, 398
vi. Of the Rose-Piece and Sun, 399
vii. Of the Manner of changing a Horizontal to a
Vertical Wheel, and representing a Sun in front, ib.
viii. Of Caprices and Fire-Wands, 400
ix. Of Palm and other Trees, 401
x. Of the Pyramid of Flower Pots, 402
xi. Of the Dodecaedron, 403
xii. Of Cascades of Fire, 404
xiii. Of Chinese Fountains, and Parasols, 405
xiv. Of Wings, or Cross Fire, 406
xv. Of Galleries of Fire, and Batteries of Roman
and Mosaic Candles, ib.
xvi. Of Girandoles, and their Modifications, 407
xvii. Of Cracking Caprices, ib.
xviii. Of the Projected Regulated Piece of Nine Mutations, 408
xix. Of the Pyric or Fire-Piece, 412
xx. Of Sundry Illuminated Figures, 413
xxi. Of the Spiral or Endless Screw, and Waved Fire, 418
xxii. Of the Decoration of Wheels, ib.
xxiii. Of Globes, with their Various Decorations, 419
xxiv. Of the Representation of the Moon and Stars, 421
xxv. Of the Representation of Sundry Figures in Fire, 423
xxvi. Of the Representation of Flat Stars with a large
Body of Fire, 424
xxvii. Of the Single, Double, and Triple Table Wheel, 425
xxviii. Of Decorations, Transparencies, and Illuminations, ib.
xxix. Of Imitative Fire-works, 440
CHAPTER XI.
Of Aquatic Fire-works, 442
Sec. i. Of Water Rockets, 443
ii. Of Pipes of Communication, ib.
iii. Of Horizontal Wheels for Water, 444
iv. Of Water Mines, ib.
v. Of Fire Globes for the Water, 445
vi. Of Odoriferous Water Balloons, 446
vii. Of Water Balloons, 447
viii. Of Water Squibs, 448
ix. Of the Water Fire-Fountain, ib.
x. Of Swans and Ducks, to discharge Rockets in Water, ib.
xi. Of Discharging Rockets under Water, 449
xii. Of the Representation of Neptune in his Chariot, 450
xiii. Of the Representation of a Sea-Fight with small
Ships, and the Preparation of a Fire-Ship, 451
CHAPTER XII.
Of the Arrangement of Fire-works for Exhibition, 452
PART IV.
Military Pyrotechny, 456
CHAPTER I.
Observations in General, 456
Sec. i. Of Cartridges, 462
ii. Of Cannon Cartridges, 467
CHAPTER II.
Of Matches, 471
Sec. i. Of Slow Match, ib.
ii. Of Priming Tubes, 475
iii. Of Quick Matches, 477
CHAPTER III.
Of Port-Fires, 479
CHAPTER IV.
Of Fuses for Shells, Howitzes, and Grenades, 481
Sec. i. Of the Method of Charging the Fuses of Bombs
or Shells, 482
ii. Of Loading Shells, Howitzes, and Grenades, 484
iii. Of Fuses with Dead Light, 485
iv. Of the Dimensions of Fuses, and the Dimensions
and Charge of Bombs, Howitzes, and Grenades, 487
CHAPTER V.
Of Incendiary Fire-works, 490
Sec. i. Of Fire Stone, 491
ii. Of Incendiary Matches, 492
iii. Of Carcasses and Fire Balls, ib.
iv. Of Incendiary Balls, or Fire Balls, to be thrown
from Cannon or by Hand, 497
v. Of Smoke Balls, 499
vi. Of Stink Balls, ib.
vii. Of Poisoned Balls, ib.
viii. Of Red-hot Balls, 499
ix. Of Pitched Tourteaux and Fascines, 500
x. Of Torches, or Flambeaux, 501
xi. Of Powder Bags, 503
xii. Of the Powder Barrel, ib.
xiii. Of the Burning, or Illuminating Barrel, ib.
xiv. Of the Thundering Barrel, 504
xv. Of the Petard, 505
xvi. Of the Stink-Fire Lance, 506
xvii. Of the Combustible Substances used in, and the
Manner of preparing, a Fire-Ship, 507
xviii. Of Infernal Machines, 512
xix. Of the Catamarin, 514
xx. Of the American Turtle, 515
xxi. Of the Torpedo, 521
xxii. Of the Marine Incendiary Kegs, 523
xxiii. Of Sea Lights, 525
xxiv. Of Signal and War-rockets, 526
xxv. Of Sky-Rockets, (_Meurtrières_,) 538
xxvi. Of the Rocket Light-Ball, 539
xxvii. Of the Floating Rocket Carcass, ib.
xxviii. Observations on Rockets, 540
xxix. Of the Succouring Rocket, 544
xxx. Of the Greek Fire, ib.
xxxi. Of Mines and Mining, 550
xxxii. Of the Means of Increasing the Strength of
Gunpowder for Mining, 554
xxxiii. Of Incendiary Bombs, 556
xxxiv. Of Murdering Marrons, 557
xxxv. Of Incendiary Rope, 558
xxxvi. Of Balloons of Grenades, of Bombs, and of
Flints or Stone, 559
xxxvii. Of Spherical Case Shot, ib.
xxxviii. Of the Fire-Rain, according to Casimir Siemienowicz, 560
xxxix. Of the Effect of Mirrors in inflaming Bodies at
a Distance, 562
xl. Of Incendiary and Poisoned Arrows, 566
xli. Of Pyrotechnical Sponge, 570
xlii. Of Extinguishing Flame with Fired Gunpowder, 572
xliii. Of the Inflammable Dart, 574
xliv. Of the Firebrand, ib.
xlv. Of the Fire Flask, 575
xlvi. Of the Trompe-Route, ib.
xlvii. Of Fire-Pots for Ramparts, ib.
xlviii. Of Inflammable Balls, 577
xlix. Of Pauly's Inflammable Powder, ib.
l. Of Extemporaneous Fire, 578
li. Of the Indian White Fire, 580
lii. Of the Pyrophore of Defence, 581
INTRODUCTION.
In presenting this work to the public as a system of Pyrotechny,
which, we have reason to believe, is the only full and connected
system that has appeared, we may be permitted to remark, that, in our
arrangement of the subject, we have appropriated separate heads for
each article.
This plan, of the subject being considered in chapters and sections,
and forming with the divisions of the work, a connected system of
arrangement, enables the reader to have a full view of the whole,
and, at the same time, all the facts in detail belonging to the
chapter, or section under consideration. By referring to the Table
of Contents, this plan will be seen without further comment. The
arrangement of the different articles in this manner, necessarily
comprehends in the onset all the substances, which are employed in
various preparations. In considering this part of our subject, we
have given the chemical characters, or peculiar properties of each
substance respectively; by which a rationale of pyrotechnical effects
may be the better understood, and, consequently, the action of bodies
on each other better illustrated.
In this part we also comprehend the General Theory of Fire-works,
which it may be proper to remark, we have drawn from the known
effects of chemical action; so far, at least, as the laws, of
affinity, which govern such action, are applicable to the subject.
The importance of this inquiry, although having no relation to the
mere manipulations of the artificer, can not be doubted; since a
knowledge of chemistry has already improved the preparation of
gunpowder, and its effects are now known to be owing to the formation
of sundry elastic aeriform fluids. On this head, that of the
application of chemistry to Pyrotechny, we claim so much originality,
as, so far as we know, to have been the first, who applied the
principles of chemistry.
It is not to be expected in every instance, that a rationale of the
decomposition as it occurs, or the order in which it takes place,
can be given with certainty; because, where a variety of substances
enter into the same preparation, which is frequently the case, the
affinities become complicated, and the laws of action for that reason
indeterminate, and frequently anomalous. But, on the contrary, in
a variety of primary operating causes, by which effects analogous
in their nature result, decomposition of course being the same, the
causes are well understood, and the effects are thereby known, and
duly appreciated.
This, for instance, is the case with a mixture of nitrate of potassa,
charcoal, and sulphur, in the proportion necessary to form gunpowder;
for, it is known, that the explosive effects of powder are owing to
the sudden production of a number of gases, which suffer dilatation
by the immense quantity of caloric liberated at the moment of
combustion. Although the production of caloric by the inflammation
of gunpowder is a case, which cannot be explained by the present
received theory of combustion, as we have noticed in that article;
yet we know that it is a fact, and that caloric is generated by the
decomposition of the powder.
If we consider the primary cause of this decomposition, we naturally
inquire into the products of the combustion, and endeavour to
account for the production of the elastic aeriform fluids. We know
that carbon has the property of decomposing nitric acid, and also
nitrate of potassa; for, when it is brought in contact in the state
of ignition with nitre, a deflagration will ensue, and carbonic acid
be formed. The quantity of this acid is in the direct _ratio_ to
the quantity of oxygen required to _saturate_ a given quantity of
carbon; and therefore, by employing certain proportions of nitre and
charcoal, the latter will decompose the former, and by abstracting
its oxygen, on the same principle form carbonic acid, while the
azote, the other constituent of nitric acid, will be set at liberty.
Nor is this all, if we consider the action of sulphur. The sulphur
must unite with one portion of the oxygen to produce sulphurous acid
gas, and also with the potassa of the nitre, and form a sulphuret, a
compound necessary to be formed, before we can explain the production
of sulphuretted hydrogen gas, which results from the decomposition
of water contained in the nitre. There also results, as a product,
sulphate of potassa. In considering these products at large, it would
be necessary to go into detail; and, as we have descanted largely on
its combustion in gunpowder, we accordingly refer the reader to the
article on _Gunpowder_. It will be sufficient, however, to remark,
that the _agent_, and consequently the cause, which produces the
decomposition of nitrate of potassa, is carbon or charcoal. This, by
uniting with the greater part of the oxygen of the nitre, produces,
in a determinate proportion, carbonic acid gas. This gas, therefore,
in conjunction with other gases, formed at the same time, all of
which being expanded, causes what is denominated the _explosive
effect_ of gunpowder.
We have then a primary cause of the decomposition, and most of the
effective force of gunpowder is owing to the carbonic acid; and it
is found, that gunpowder made without sulphur is equally powerful as
that with, since it adds nothing to its power.
Causes, therefore, chemically speaking, operate alike under similar
circumstances. The materials made use of being equally pure, and used
in the same proportion, the effect must necessarily be the same.
It is not only in the instance we have mentioned, but in every other,
in which chemical action ensues, that this doctrine is tenable.
We might, indeed, notice a number of cases of a similar kind; as,
for instance, in the combustion of many incendiary preparations,
as fire-stone, fire-rain, composition for carcasses, light-balls,
and a variety of fire-works of the same kind. If we mix pitch, tar,
tallow, &c. with nitrate of potassa, and burn the mixture, we have
the combined action of two elementary substances, which enter into
the composition of these bodies, namely, carbon and hydrogen. The
products would be carbonic acid gas, and water; because the oxygen of
the nitre would unite with the hydrogen, as well as the carbon. If we
employ sulphur at the same time, another product would be sulphurous
acid gas, and probably sulphuric acid; and if gunpowder be used, as
in the _fire-stone_ composition, then, besides these products, we
would have those of the gunpowder.
As this subject, however interesting to the theoretical pyrotechnist,
cannot be understood without a knowledge of chemistry, it is obvious,
that that science is a powerful aid to pyrotechny. It is unnecessary
to dwell on this head. We may add, nevertheless that, in order to
understand the effect of all mixtures, or compositions made use of,
it is necessary to consider the nature of the substances employed,
and the manner in which chemical action takes place, and consequently
the products, which determine in fact the characteristic property
of each species of fire-work, and the phenomena on which it is
predicated. All products of combustion depend on the substances thus
decomposed, and by knowing the effects, we may readily refer them to
their proper causes.
With respect to _caloric_, it may not be improper to offer some
remarks.[1] The hypothetical element of phlogiston having given
way to the antiphlogistic theory at present received, our ideas
respecting caloric are predicated on facts. Caloric is a term, which
expresses heat, or matter of heat. In pyrotechny, we have merely to
consider it in a free, or uncombined state; but as the subject is
interesting, we purpose to notice it very briefly under the following
heads: viz. its nature; the manner it is set in motion; its tendency
to a state of rest; the changes it produces on bodies; and the
instruments for measuring its intensity.
As to the nature of caloric, different opinions are entertained.
We know the effect of heat: if we touch a substance of a higher
temperature than our bodies, we call it hot, and _vice versa_. The
one is evidently the accession, and the other the abstraction, of
caloric. The latter is merely relative as respects ourselves; for the
effect depends on our feelings, and the sensation of hot or cold is
therefore governed by them.[2] Caloric, however, is considered to
be a substance, composed of inconceivably small particles; but count
Rumford and sir H. Davy are of a contrary opinion, namely, that it
depends upon a peculiar motion and not on a subtle fluid.
As the effect of caloric, according to their view, depends on motion,
the agencies by which this is effected are of the first importance.
That it exists in all bodies in a state of rest, and in a greater or
smaller quantity, and consequently in a relative proportion, is well
known, and on this, the capacities of bodies for caloric is founded.
The capacities of bodies for heat are changed by various means, and
caloric is put in motion; and, according to its quantity, the bodies
may be either cold or hot. When the surrounding bodies become heated,
they receive this caloric thus set free, and, in this view, the
absolute quantity of their heat is increased. This state of rest, to
which caloric is subject, may be destroyed either by an increase or
a diminution of the capacity of a body. If caloric be put in motion
by causes of any kind, which influence the capacities of different
bodies, a theory maintained by Davy, then as the capacity for heat
is changed so is free heat produced. Diminish the capacity of a
body, its excess will of course be given out, and distribute itself
among the surrounding bodies, which become heated; but increase
the capacity, and a different effect ensues. The body absorbs
caloric, by which its capacity is increased, and cold is produced.
Caloric, whether considered a substance, or an attribute, possesses,
nevertheless, this property, that when it is given out, as in the
mixture of sulphuric acid and water, which occupies a less space than
both in a separate state, the sensation of heat follows; and when it
is absorbed, as in the various freezing mixtures, or in a mixture of
snow and common salt, the sensation of cold is excited. The causes,
however, which set caloric in motion, or that produce heat, are such
as combustion, condensation, friction, chemical mixture, and the
like. It is remarkable, that these effects are invariably the same,
and are affected by corresponding affinities. When a piece of iron
is struck with a hammer, the percussion produces a condensation of
the iron, its specific gravity is increased, and the iron finally
becomes ignited. The condensation of air, in the condensing syringe,
will set fire to tinder. The flint and steel produce a condensation;
for the metal, although small, is sent off in scintillations in
the state of ignition. That caloric is contained in bodies in the
state of absolute rest, and is evolved by condensation, there is no
doubt. Gunpowder, by percussion, in contact with pulverized glass, is
inflamed; and it appears very probable, that it also contains caloric
in a state of rest. The experiments of Lavoisier and Laplace, on the
quantity of caloric actually absorbed in nitric acid, and in a latent
state, (noticed in the article on _gunpowder_), are satisfactory.
If caloric is not in that state in nitre, how are we to explain the
sudden transmission or evolution of caloric in fired gunpowder, where
no external agent in any manner can influence the formation, or
disengagement of caloric? Friction or attrition produces heat; and
the distributable excess of caloric, as it is called, although not
satisfactorily accounted for, may arise from a condensation; which,
however, is denied.
The Esquimaux Indians kindle a fire, very expeditiously, in the
following manner: They prepare two pieces of dry wood, and making a
small hole in each, fit into them a little cylindrical piece of wood,
round which a thong is put. Then, by pulling the ends of this thong,
they whirl the cylindrical piece about with such velocity, that the
motion sets the wood on fire, when lighting a little dry moss, which
serves for tinder, they make as large a fire as they please; but as
the little timber they have is drift wood, this fails them in the
winter, and they are then obliged to make use of their lamps for the
supply of their family occasions. _Ellis's Voyage for the Discovery
of a North-West Passage._
Friction is, therefore, one means of producing distributable heat,
which is also exemplified very frequently in the axis of a carriage
wheel; of mill work; in the rubbing of wood, when turned on its axis
in a lathe, by which turners ornament their work with black rings;
rubbing a cord very swiftly backwards and forwards against a post or
tree, or letting it run over a boat, &c. as in the whale fishery;
the motion of two iron plates against each other, pressing them at
the same time, &c. The great object in the construction of machines
is to avoid, or lessen the degree of friction. See Hatchette, Vince,
and Gregory. Count Rumford (Nicholson's Journal, 4th edit. ii, 106),
and professor Pictet (_Essai sur le Feu_, chap. ix.) have made some
valuable experiments on heat evolved by friction.
The sun is one great source of caloric. In whatever mode it produces
it, whether by giving it out from its own substance, by the action
of light on the air that surrounds the globe; by the concentration
of calorific rays by means of the atmosphere, acting as a lens; or
by putting caloric in the distributable state, always pre-existing
in some other, as in a state of rest, are questions, which, in our
present state of knowledge, we are unable to solve. We know the
fact, and that the caloric is of the same nature as that obtained by
combustion.[3]
Combustion is a process by which caloric is put in a distributable
state. The opinion of Stahl and others, that all combustible bodies
contained a certain principle called phlogiston, to which they owed
their combustibility, and that combustion was nothing more than a
separation of this principle, gave rise to the phlogistic or Stahlian
theory, which was afterwards modified by Dr. Priestley. But his
theory is equally untenable. Kirwan's opinion was no less vague,
although he substituted hydrogen for phlogiston.
The Lavoiserian, or antiphlogistic theory overturned the Stahlian.
According to this theory, a combustible in burning unites with
oxygen, and heat and light are given out by the gas, and not from
the combustible. According to a modified theory of the above, by Dr.
Thomson, caloric is evolved by the gas, and light from the burning
body. Without noticing the instances, in which this theory, as a
general one, is insufficient to explain the cause of combustion, or
of the production of heat and light, we will merely remark, that
bodies which support combustion are called supporters, as oxygen gas,
chlorine gas, &c. and those, that undergo this change, are named
combustible bodies.
The products of combustion may be fixed or gaseous, and either
alkalies, oxides, or acids; or, when chlorine is the supporter,
chlorides, &c. A few examples will be sufficient. By the combustion
of metals, iron for instance, we obtain a fixed product, and in
the present case an oxide of iron; by the combustion of antimony
and arsenic, the antimonic and arsenic acids; by the combustion
of charcoal, we have carbonic acid gas, a gaseous product; by
the combustion of potassium or sodium, we obtain a fixed alkali,
depending however on the quantity of oxygen; by the combustion of
sulphur, phosphorus, &c. acids; and when metals are burnt in chlorine
gas, chlorides are produced.
It is evident from facts, that, whatever theory may be assumed,
combustion occasions the production of _free_ caloric, or changes
the _condition_ of caloric, from quiescent to distributable heat.
The conclusions drawn by Mr. Davy and others, appear to have been
predicated on the absorption of the base, and development of caloric,
as in oxygen gas, and the peculiar alteration in bodies implying a
decrease in their capacity; and hence, as regards the products of
combustion, they must necessarily possess a less capacity for heat
than the mean capacity of their constituents.
Whether we regard heat as latent, in the acceptation of the term, as
applied or used by Dr. Black, or quiescent, or in a state of rest, it
is certainly evident, that combustion is a chemical change, and by it
caloric passes from a combined to an uncombined state, and is thus
made sensible, free, or thermometrical heat. Combustion may, as it
certainly does, put quiescent heat in a distributable state; but this
quiescent heat is the same in the present case, of which there can
be no doubt, as latent caloric. The thermometer will only indicate
as much caloric in the air as is in a distributable, or free state;
but, if the same air be employed to supply, or support combustion,
the heat, rendered appreciable by the senses and the thermometer,
will be in the ratio of the decomposition of the oxygen gas of the
atmosphere, and, of course, to the development of free caloric.
Chemical combination, such as occurs by the mixture of fluids, as
alcohol and water, sulphuric acid and water, some of the gases,
as muriatic acid gas with water, &c. evolves heat, and sometimes
sufficient to boil water. In cases of spontaneous combustion, it
would seem, that quiescent heat passes to the state of distributable
heat; for if nitric acid, for instance, contains so large a quantity
of quiescent heat, or fixed heat, as the experiments of Mr.
Lavoisier make it appear, we may readily explain why spontaneous
combustion ensues, when that acid is brought in contact with spirits
of turpentine; because the chemical action of the acid on the carbon
and hydrogen of the turpentine, which takes place, produces at the
same time a corresponding change in the caloric itself, from a
quiescent to a distributable state. If the same data be admissible
with regard to the combination of the nitric acid with potassa, which
we may judge to be the case by the experiments of Lavoisier and
Laplace, (quoted in our article on _Gunpowder_), then, indeed, its
mechanical union with charcoal, and sulphur, although in a common
temperature no combustion ensues, will, at the temperature required
to inflame the mixture, (about 700 degrees according to some),
produce a decomposition altogether chemical; and while new products
are formed, the caloric, necessary also for their generation, passes
from a quiescent to a distributable state; and a portion of it goes
into a new state of combination, also quiescent. We mean that portion
which is necessary for the constitution of gaseous fluids. This
fact is remarkable. By referring to the original state or condition
of the caloric, if we admit that state in the present instance,
(which appears the only mode of accounting for the emanation of free
caloric by the combustion of gunpowder), it is easily perceived, that
chemical changes, besides the usual supporters of combustion being
concerned, as in ordinary cases of combustion, must produce a similar
change in the state of combined or quiescent heat.
Predicating this opinion on the results of the experiments of MM.
Lavoisier and Laplace, and seeing that gunpowder inflames _per se_,
or without the aid of a gaseous supporter, we have no hesitation in
risking it, in the present state of our knowledge concerning heat as
our present belief and conviction. Although there is no satisfactory
theory offered to explain all the instances of spontaneous
combustion, yet it seems reasonable to conclude, that in many cases
at least, that effect may take place by some chemical action,
which, like the instances already quoted, may change quiescent
into distributable heat. We have stated (See _Gunpowder_) some
instances of spontaneous combustion, which have taken place merely
in consequence of the charcoal. Some have attributed the effect to
pyrophorus, and others to the presence of hydrogen in the coal,
which, by absorbing and combining with oxygen and forming water,
sets the caloric of the oxygen gas at liberty, and thus produces
combustion. However this may be, there are other instances, that of
cotton and oil, some kinds of wood, wood-ashes and oils, &c. which
have produced spontaneous combustion.
We will only add, however, that until we can give a better theory,
the effect in these instances may be attributed to chemical action,
and _with it_, the change of caloric in the manner already mentioned.
Chemical action in such cases appears necessary, although mechanical
means, as percussion will produce heat.
Quiescent heat is also put in motion by electricity; but in what
manner it acts, so as to produce that effect, is unknown. It is a
powerful agent in nature, and calculated for important ends, of which
we are ignorant. It is unnecessary to notice opinions concerning it.
All electrics will yield it, such as glass, rosin, &c. and it may
be collected in the usual manner by the prime conductor and Leyden
jar. Galvanism, called also Galvanic electricity, produced by an
arrangement of zinc, and copper plates in a pile, or trough, and
placed in contact with some oxygenizing fluid, has the same effect of
causing quiescent heat to become distributable, and is undoubtedly
the result of chemical action. The peculiar character of this fluid,
the nature of the two opposite poles, &c. have been, and continue
to be, a subject of interest to the philosopher. The _deflagrator_
of professor Hare of Philadelphia is an apparatus well calculated
for many interesting experiments on galvanism. To that gentleman, we
are also indebted for the compound blowpipe, which produces a very
intense heat by the combustion of hydrogen in contact with oxygen
gas. Notwithstanding professor Clark of England has laid claim to the
apparatus, and the use of hydrogen gas in this way, the merit of the
discovery is due to our learned and ingenious countryman.
Since heat is put in motion as a consequence of the increased
capacity of a body, and, by combining with a substance whose capacity
has been increased, becomes by degrees quiescent, according to
the respective capacities of bodies; cold is an effect, which is
occasioned by this change from a free to a combined or quiescent
state. The absorption of heat, necessary for the generation of
cold, if so we may consider it, takes place in every instance,
where that effect is observed. The heat of surrounding bodies, in a
distributable state, is now no longer characterised as such; and the
consequence is, therefore, that that particular sensation, or effect
follows.
Cold may be produced by saline mixtures, the salts for which having
their full quantum of the water of crystallization; and by the
evaporation of fluids, as water, alcohol and ether. In the one
case, that of the freezing mixtures, we have seen, that the effect
is produced by the _absorption_ of heat; and with regard to the
cold produced by fluids, even in _vacuo_, (where the effect is more
instantaneous), the cause is attributable to evaporation; for the
fluid changes from a liquid to an aeriform state, and during this
transition robs the body, with which it was in contact, of a part of
its caloric, and thereby reduces its temperature. Artificial ice is
made on this principle.
The next subject with regard to heat, is the different modes in which
it tends to a state of rest. There are some facts in relation to this
subject worthy of notice; and particularly, that, in the tendency of
caloric to become quiescent, after having been put in motion, bodies
often increase in temperature. This tendency to a state of rest is
effected either by the conducting power of bodies, or radiation.
Heat radiates in all directions, and in quantities, according to
the experiments of Leslie, more or less variable, which depend on
the nature of the radiating surface. Hence that power, which bodies
possess, called the radiating power, varies in different substances.
Thus, the radiating power of lampblack is 100, while gold, silver,
copper, and tin plate are 12, from which it appears that the metals
distribute less heat by radiation. That caloric obeys the same
laws as light, is obvious from Pictet's experiments with concave
mirrors, where the calorific rays move in the same order, the angle
of incidence being equal to the angle of reflection. It is also
refracted; hence the concentration of the solar rays in a focus by
the burning glass. Various experiments have been made with mirrors,
and concave reflectors. The effect of the former in destroying the
fleet before Syracuse, an experiment made by Archimedes, is a fact
well authenticated in history. Concave reflectors have inflamed
gunpowder. This subject, however, is noticed at large, when speaking
of mirrors as an incendiary in war.
That bodies conduct heat, and with different degrees of power, so
that some are called good and others bad conductors, is well known.
This property depends on the quantity of caloric, which a body
receives, before it changes its state. Metals are considered good
conductors, and glass, charcoal, feathers, &c. bad conductors. Hence
bad conductors, as wool, &c. preserve the temperature of the body,
or keep it _warm_ in winter; and snow, for the same reason, prevents
the action of intense cold on the ground. Liquids also conduct heat.
Whether we consider caloric in this case carried, or transported,
as it is more properly defined, the fact may be shown by several
experiments. Ebullition, or boiling, is a phenomenon, which depends
on the increment of temperature; for as water, for instance, receives
caloric, until the thermometer indicates 212 degrees, the boiling
point, mere evaporation ensues; but that temperature, under the
usual pressure of the atmosphere, causes the formation of bubbles at
the bottom of the vessel, as that part receives the degree of heat
necessary for ebullition before any other; and these bubbles, as they
form, rise in succession, and pass off in the state of steam, while
the circumjacent fluid takes its place, and the process continues
till all is boiled away. Water, when it passes off in the state
of steam, which requires a degree of heat equal to 212 degrees of
Fahrenheit, receives also 1000 degrees of non-distributable caloric,
or latent heat; and however singular the fact may appear, the wise
Author of Nature, it seems, has reserved a _store of caloric_, in
this form, ready to be put in requisition, when necessity demands it,
in a distributable shape.
Caloric, when in a state of rest, exists in different proportions,
and although the actual temperature may be the same, yet the quantity
of caloric in a quiescent state may be variable. There are several
experiments, which are adduced to illustrate this fact. It results
from experiment, that bodies receive heat according to their several
capacities for it; hence, when any number of bodies are differently
heated, the caloric, which becomes latent, does not distribute itself
in equal quantities, but in various proportions, according, as we
remarked, to their several capacities. Caloric, therefore, in a
state of rest, is in relative quantities; and as the capacity of
bodies for heat is variable, and relative as to each other, the term
_specific caloric_ has been applied. From these conclusions, we may
readily perceive what is implied by an equality of temperature. That
it merely depends on the state of rest, which caloric necessarily
comes to, and which is relative as respects the capacity of bodies,
and nothing more, is a deduction very plain and obvious. Heat, in a
state of motion, may be said to be progressing to a quiescent state;
and equalization of temperature, although differently understood,
may be considered an equalization of fixed caloric, according to the
relative capacity of bodies, without regarding the equalization,
which takes place of uncombined caloric, as is manifested by
thermometrical instruments. In a word, by considering caloric in this
view, that of tending to a state of rest, and uniting with bodies
according to their respective capacities, we may account for many
phenomena; as, for instance, the quantity of caloric which enters
into ice, and becomes latent, during liquefaction. The quantity of
caloric, in this respect, may be learnt by adding a pound of ice at
32 degrees to a pound of water at 172 degrees. The temperature will
be much below 102 degrees, the arithmetical mean, viz. 32 degrees.
It is evident that the excess of caloric has disappeared; and by
deducting 32 degrees from 172 degrees, 140 degrees remain, which
is the quantity of caloric that enters into a pound of ice during
liquefaction, or the quantity required to raise a pound of water from
32 degrees to 172 degrees. This change of capacity appears to be
absolutely essential to the well being of the universe, as affording
a constant modification of the action of heat and cold, the effects
of which would otherwise be inordinate. If this did not take place,
the whole of a mass of water, which was exposed to a temperature
above the boiling point, would be instantly dissipated in vapour with
explosion. The polar ice, would all instantly dissolve, whenever the
temperature of the circumambient air was above 32 degrees, if it were
not that each particle absorbs a quantity of caloric in its solution,
and thereby generates a degree of cold which arrests and regulates
the progress of the thaw; and the converse of this takes place in
congelation, which is in its turn moderated by the heat developed
in consequence of the diminution of capacity, which takes place in
the water during its transition to a solid state. The reason why
boiling water in the open air never reaches a higher temperature than
212 degrees is evident, if we consider, that the capacity of those
portions of liquid, which are successively resolved into a vapour,
becomes thereby sufficiently augmented to enable them to absorb the
superabundant caloric as fast as it is communicated.
The most obvious effect of caloric on bodies, is the change, which
they undergo when exposed to its action.
That it acts constantly in opposition to the attraction of cohesion
or of aggregation, by which bodies pass from a solid to a fluid,
and from a fluid to an aeriform state, and produces also different
changes in bodies,--are facts that come under our daily observation.
It occasions changes in the bulk of bodies; hence solids, liquids,
and gases are expanded. The expansion, and subsequent contraction
of atmospheric air, give rise to various winds, which are currents
of air rushing from one point of the compass to another to maintain
an equilibrium. The theory of the winds is predicated on this fact,
although some have asserted, that they depend greatly on the diurnal
motion of the earth. The air thermometer of Sanctorius, and the
differential thermometer of Leslie, are founded on this principle, of
the expansion of air. Fluids expand until they arrive at the boiling
point, as is the case with water, alcohol, &c. The expansion of
mercury, in a glass tube, furnished with a graduated scale, forms the
mercurial thermometer, by the rise and fall of which, the different
variations of temperature are marked.
Notwithstanding caloric has the property of expanding bodies, there
are some exceptions to this law, which may be proper to notice.
Water, for instance, at the temperature below 40° contracts at every
increment of temperature until it reaches 40°, which is its maximum
of density. Above 40° it expands, until it arrives at the boiling
point. Alumina, or pure argillaceous earth, also contracts by heat;
hence it is used in the pyrometer of Wedgwood, to measure by its
contraction intense degrees of heat. Various saline substances, in
the act of crystallization, also expand. Several of the metals, when
previously melted, on cooling exhibit the same character; and water,
in the act of freezing, exerts a powerful force by its expansion,
competent to the bursting of shells, and the splitting of rocks.
The changes in bodies, produced by caloric, we have already noticed.
We will only add, that fluids require different temperatures, called
the boiling point, to make them boil, under the same atmospheric
pressure. Water boils at 212°. Many observations have been made
with respect to water, both in the state of ice, and the state of
vapour. Besides the accession of 212 degrees of caloric, appreciable
by the thermometer, in water in the state of steam, there is also
an accession of non-distributable caloric, called _latent heat_,
which is calculated at 1000°. In consequence of this circumstance,
steam has been judiciously applied to various useful purposes, and
particularly in a certain manner for the drying of gunpowder.
That chemical changes are produced by the agency of caloric, is a
fact well known. It is supposed to occasion decompositions, according
to the laws of affinity, by changing previous affinities, and causing
new affinities to take place. Hence the operations by fire, whether
the substances themselves are exposed in a dry state to the action
of heat, or otherwise, produce new results, or compounds, which
could not be made without it. This truth has long been obvious.
In consequence of a knowledge of this fact, Dr. Black (_Lectures_
vol. i, p. 12,) defined "chemistry to be the study of the effects
of heat and mixture, with the view of discovering their general and
subordinate laws, and of improving the useful arts."
Caloric as a powerful auxiliary, performing as it does an innumerable
multitude of changes and effects, an agent by which the operations
of the universe are maintained in order and harmony for universal
good, exerts the same effect in the furnace of the chemist, as in
the great laboratory of nature; and regulates, and determines all
the consequences, which follow a succession of fixed, and appointed
changes.[4]
We have thus, in this brief and hasty outline of the nature,
principal effects, and properties of caloric, detailed the leading
facts on this subject; from which it will be seen, that caloric,
so far as respects its generation by the combustion of different
pyro-mixtures, and effects, generally, should form a part of
Pyrotechny, and claim the attention of those, who are connected with
the preparation of Fire-Works.
Respiration is also a process which puts quiescent heat in motion.[5]
In the second part of the work, we embrace the furniture of a
laboratory, for the use of fire-workers, consisting of various tools
and utensils.
Under this head, we also embrace sundry manipulations, such as the
preparation of substances for use, the manner of forming mixtures,
and various anterior operations. The formation of pasteboard for
cases, the mode of forming as well as charging cases, different
modes of charging rockets, the dimensions of rammers, mallets &c.
This preliminary ought to be well understood; as the successful
practice of the art depends greatly on these operations. We may
observe, however, that we have had occasion to repeat some of these
manipulations in certain instances, to make them more intelligible;
or rather to present, more in connection with the subject, a detail
of minutiæ.
In the different compositions, the reader will bear in mind, that
the copious collection of formulæ, both old and new, embraces all
the facts, with which we are acquainted, concerning pyrotechnical
preparations.
In most instances, where the importance of the subject required it,
we designated, or set apart from the rest, formulæ, which have been
_approved_, and particularly in France.
This is more particularly the case as it respects the fourth and
last part, which appertains exclusively to Military Fire-Works. On
this subject, permit me to remark, that fire-works, intended for the
purposes of war, should be depended on; and for that reason, in order
to produce a certain effect, the materials of which they are composed
should be pure, weighed with accuracy in the proportions required,
and carefully mixed according to the rules laid down. It is true,
however, that while this nicety is required in particular cases, it
is unnecessary in the formation of all fire-works. The composition
for carcass and light-ball, for tourteaux, links, and fascines, and
some others, do not require that precision; whereas the composition
for fuses for bombs, howitzes, and grenades should be in every
respect accurately made; for on the accuracy of the composition, must
depend the time a fuse will burn, which is afterwards regulated by
using more or less of the fuse, according to the time it will take
for the shell to reach its destination, on which depends the skill of
the bombardier. Accuracy, however, in making of preparations should
be a general rule.
Viewing Pyrotechny either as a science or an art, there is
undoubtedly required in its prosecution much skill and practice. A
knowledge of the theory of fire-works may be readily acquired. The
mere artificer or fire-worker, by constant habit and experience, may
understand it is true how to mix materials, prepare compositions,
charge cases, and perform all other mechanical operations; but it is
equally certain, that, without a knowledge of chemistry, he cannot
understand the theory. We would not say, that the workman should be
a chemist, but that he should know enough to determine the purity
of the substances he employs, and their respective qualities and
effects; for if that principle were admitted, we might go further
and say, that every person, who practices a chemical art, as the
tanner, gluemaker, brazier, &c. should be a chemist, or that the art
could not be conducted without a previous knowledge of chemistry,
which we know is contrary to fact. This, however, may be said, that
in _all_ arts which are decidedly chemical, as that of _dying_ for
instance, chemical knowledge will enable the artist or operator to
conduct his processes with better advantage, and correct any _old_
routine, which is too often pursued, because it was handed down
from generation to generation. Mr. Seguin in France facilitated the
preparation of tanned leather, by adopting a new process altogether
chemical. In a word, so far as chemistry is connected with the
arts, and by which we explain the operations that take place, it is
undoubtedly important; and with regard to Pyrotechny, it appears, in
the way we have mentioned, to be indispensable. Chaptal (_Elements de
Chimie_) observes, that the works of artificers frequently miscarry
in consequence of their being unacquainted with the art.
In noticing this subject, we may be permitted to digress, while we
state, that, being fully convinced of this truth, we have directed
our labours in the Chemical Department of the United States'
Military Academy to two distinct objects; _viz._ to theoretical
and experimental chemistry, forming the first year's course, and
chemistry in its application to the arts, manufactures, and domestic
economy, constituting, along with mineralogy, the course of the
second year. In addition to the usual applications, Pyrotechny, in
the manner we have stated, and especially that branch which treats of
military fire-works, has claimed our attention; and we have reason
to believe, that this addition, to the usual course of chemical
instruction, has considerably advanced the utility, especially to
gentlemen designed for the army, of the application of chemistry.
The system of instruction adopted throughout the academy, in the
different departments, (the plan of which may be seen in the new
_Army Regulations_, article Military Academy), which, we have no
hesitation in believing, is the most complete of any in the United
States, and by far the most extensive,[6] is so regulated, that each
section of a class regularly recite, and are interrogated on each
subject of instruction, so that, while an emulation to excel is thus
excited, the comparative merit or standing of the cadets is thereby
determined. Adopting the same system in the Chemical department,
that of interrogation on the subject of the preceding lecture, has
many peculiar advantages; so that, while the mind and memory of the
pupil are thus exercised, a comparative estimate of the progress of
each one is obtained during each week, by which we are enabled, as in
other departments, to present a Weekly Class Report of their progress.
While we are indebted to the talents and industry of the professors
and teachers of the Academy, for the flourishing condition it is now
in, and the progress of the cadets in every branch there taught; it
is but justice to remark, that for the present organization of the
academy, as relates to the studies, which is obviously preferable to
the old system, and also for the improvements in instruction, we are
indebted to the present superintendent, Col. S. Thayer, of the U. S.
corps of engineers.
Considering pyrotechny, abstract from the questions usually given,
and forming a distinct branch, it may be proper to remark, that the
interrogatories on this head have been minutely and satisfactorily
answered. The following outline will exhibit the order in which such
questions were put, observing, however, that they are merely in
connection with this subject:
What is saltpetre? What is nitric acid? What is potash? What are
the sources of saltpetre, and how is it obtained? How is it formed
in nitre beds, extracted, and refined? What circumstances are
necessary to produce nitre, and how does animal matter act in its
production? What is the difference between the old and new process
for refining saltpetre? What reagents are used to discover the
presence of foreign substances in nitre? What are nitre caves? Where
do they exist? What are the nitre caves of the Western country,
and how is nitre extracted from the earth? What proportion of
nitre does the saltpetre earth of the nitre caves afford? What is
the theory of the process for extracting saltpetre from nitrous
earth, or nitrate of lime? What is sulphur? How is it obtained,
and how is it purified for the manufacture of gunpowder? Of what
use is sulphur in the composition of gunpowder? Does it add to the
effective force of gunpowder? What is charcoal? What is the best
mode of carbonizing wood for the purpose of gunpowder? What woods
are preferred for this purpose? In the charring of wood, what part
is converted into coal, and what gas and acid are disengaged? What
is the use of charcoal in gunpowder? What is gunpowder? What are
considered the best proportions for forming it, and what constitutes
the difference between powder for war, for gunning, and for mining?
How does the combustion of gunpowder take place? Can you explain why
combustion takes place without the presence of a gaseous supporter of
combustion, as gunpowder will inflame in vacuo? What are the products
of the combustion of gunpowder? What gases are generated? To what
is the force of fired gunpowder owing? What are the experiments of
Mr. Robins on the force of gunpowder? How would you separate the
component parts of gunpowder, so as to determine their proportions?
What are gunpowder proofs? What is understood by the comparative
force of gunpowder? What are eprouvettes? &c. In noticing in the
same manner the preparations used for fire-works, and for war, as
the rocket for instance, the following questions were propounded;
_viz._ What is a rocket? How is it formed? Is the case always made of
paper? What is the war rocket? What is the composition for rockets,
and how does it act? What particular care is required in charging
a rocket? What is the cause of the ascension of rockets? What is
the use of the conical cavity, made in a rocket at the time it is
charged, or bored out after it is charged? How do cases charged with
composition impart motion to wheels, and other pieces of fire-work?
What is understood by the rocket principle? What is the rocket stick,
and its use? Is the centre of gravity fixed, or is it shifting in the
flight of rockets? How are rockets discharged? What is the head of a
rocket? What is usually put in the head? Are all rockets furnished
with a head? What is understood by the furniture of a rocket? How
are the serpents, stars, fire-rain, &c. forming the furniture of
a rocket, discharged into the air, when the rocket has terminated
its flight, or arrived at its maximum of ascension? What forms the
difference between a balloon, in fire-works, and a rocket? As the
balloon contains also furniture, and is projected vertically from a
mortar, how is fire communicated to it, so as to burst it in the air?
Is the fuse used, in this case the same as that for bombs, howitzes,
and grenades? What is the Asiatic rocket? The fougette of the French?
In what seige were they employed with success by the native troops of
India? What was the nature of their war-rocket? What is the murdering
rocket of the French? Is the conical head hollow, or solid, blunt or
pointed? Why is it called the murdering rocket? What is the Congreve
rocket? Is Congreve the inventor, or improver of this rocket? What
are Congreve rockets loaded or armed with? In what part is the load
placed? Is the case made of paper or sheet iron? What are the sizes
of Congreve rockets?
What are the ranges of Congreve rockets? What angle of elevation
produces the best range? How are Congreve rockets discharged in the
field, and what number of men are usually employed for that service?
Are the Congreve rockets considered to be a powerful offensive
weapon; and, if so, in what particular? What is a carcass rocket?
As an incendiary, is the carcass rocket equal to the usual carcass
thrown from mortars? What is the carcass composition made of? What is
the Congreve rocket light ball? In large rockets, are their sticks
solid, or bored and filled with gunpowder? Why is that expedient
used? &c.
It is obvious, that the student, after obtaining a knowledge of each
subject by the preceding lecture, accompanied with demonstrations, is
enabled to detail minutely all the facts in relation to it.
Pyrotechny, as known at present, is confined to a few books, and
scattered in a desultory manner, without any regular or connected
system. In fact the works which treat on this subject are in French,
or translations from the French on particular subjects, but generally
very imperfect. As applied to the uses of war, we may indeed say,
that the small treatise of Bigot, (_Traité d'Artifice de Guerre_),
and Ruggeri (_Pyrotechnie Militaire_) are the only works. We have,
therefore, consulted these authors, as will be seen in the pages of
the work.
Roger Bacon, in his _Opus Majus_, has given some account of the Greek
fire, and of a composition, which seems to have had the effect of our
modern gunpowder.
Malthus (_Traité de l'Artillerie_) contains some formulæ for Military
Fire-Works. Anzelet and Vanorchis, in their several works, have given
some receipts for incendiary preparations. Henzion (_Recreations
Mathématiques_) and Joachim Butelius have also something on the
subject.
The celebrated Polander, Casimir Siemienowicz, has nothing of any
moment, if we except the incendiary fire-rain, an account of which
may be seen in the fourth part of our work. His book is considered,
however, the best of the whole of them. Belidor, Theodore Duturbrie,
&c. have mentioned some preparations; but their works are chiefly
confined to artillery.
The improvement of Pyrotechny is ascribed to the Germans and
Italians, and the French acknowledge, that they are indebted for a
knowledge of it to the Italians. Be this as it may, it is certain,
that it was known in China from time immemorial. Their acquaintance
with gunpowder, before it was known in Europe, is a fact which
appears to be generally admitted. For an account of the Chinese
fire-works, and the origin of gunpowder in Europe, consult these
articles respectively.
Whatever merit we may claim in this work, as the public will be able
to judge impartially, it will be seen, by referring to the different
chapters and sections, that we have endeavoured to form a system, by
presenting a connected view of the whole subject.
Having noticed under separate heads, the particular use and
application of each composition, we have added a chapter on the
arrangement of fire-works for exhibition, together with the order
to be observed. We may remark here, that we have enlarged in this
part more perhaps than its merit or importance deserves; but, on
reflection, we thought it better to embrace the whole subject, in
order to form a more complete system in all its parts.
After going through the fire-works for exhibition, and noticing the
different formulæ, and preparations, for arrangement, with the
theory of effects, we consider, in the next place, a subject of
more importance, that of Military Pyrotechny. We have adopted this
arrangement, more on account of obtaining a better acquaintance with
ordinary fire-works, before the reader is prepared for military
works, which he will understand with more facility; for all the
preliminary operations precede the practical part.
On this head, it will be sufficient to add, to what we have already
stated, that we have given in each article, generally speaking, a
variety of formulæ, with ample instructions for the preparation of
each composition. The table of contents will exhibit the order in
which they are treated.
In noticing the substances used in fire-works, in the first part, it
will be perceived, that we have noticed some of them more extensively
according to their importance; as for instance, _saltpetre_. Besides
the different modes of obtaining saltpetre in Europe and elsewhere,
and the means employed for refining it, we mention the saltpetre
caves of the western country, which furnish an abundance of this
article, and which contain an almost inexhaustible supply.
The extraction of saltpetre from the earth, (principally nitrate of
lime), by using a lixivium of wood-ashes; the formation of rough,
and subsequently of refined nitre; the various methods of refining
saltpetre, and particularly that adopted in France; with sundry facts
respecting the origin of nitre, and on the formation of artificial
nitre beds; all claim our particular notice.
The extraction of sulphur from its combinations, and the means used
for purifying it for the purpose of gunpowder, are also considered in
the same manner.
The subject of charcoal, an essential constituent of gunpowder,
claims, in like manner, particular attention. The various modes
of charring, the woods employed, the quantity of coal obtained,
the formation of pyroacetic acid in the process of carbonization,
and many facts of the same kind are considered. These subjects,
_viz._ nitre, charcoal, and sulphur, are highly important to the
manufacturer of gunpowder.
A knowledge of the various processes for refining saltpetre; the best
and most approved modes of carbonizing wood; the purification and
quality of sulphur; the different processes for making gunpowder,
with the proportion of the ingredients used in France and elsewhere;
the granulation, glazing, and drying of powder, the use of the steam
apparatus, and the different modes of proving it, and of examining
it chemically; and the means of ascertaining the purity of nitre in
any specimen of gunpowder; are, with others, subjects of particular
interest to the gunpowder manufacturer.
With respect to the Theory of the explosion of gunpowder, we have
noticed it at some length, and have added the experiments and
observations of Mr. Robins, and of other persons, made at different
periods.
In the consideration of the gaseous products, and the caloric evolved
by the combustion of powder, we have taken a view of the gases
produced, the cause of their production, the dilatation which they
suffer, and the experiments of Lavoisier and Laplace, with regard to
latent heat, and deducing therefrom some views of the probable cause
of the production of caloric in fired gunpowder.[7]
Our observations respecting rockets, the theory of their ascension,
of the Congreve carcass and Asiatic rockets, and some others, are
we apprehend sufficiently extensive. As it regards the different
incendiary compositions, and their use in war, the reader will find
ample instructions on these heads.
We may also remark, that we have given some of the more common, or
general properties of the substances, employed in the composition of
fire-works, without going into that detail, which belongs exclusively
to works that treat of Chemistry. It was neither our design, nor have
we given, for the reasons thus stated, _all_ the chemical characters
or properties of the substances so employed; and, therefore, have
confined ourselves, generally speaking, to an enumeration of such
properties as are connected with the subject, or are indispensably
necessary to be known, before a rationale of the causes and effects
can be understood.
It was our intention to accompany the work with plates, exhibiting
the arrangement, &c. of fire-works, which, there can be no doubt,
would have facilitated in particular the knowledge of forming, and
arranging, certain pieces of fire-work; but, on second reflection, as
such illustrations were connected more with fancy exhibitions, and
have little or no relation to Military Fire-works, the most useful
branch of Pyrotechny, we were finally of opinion, that the addition
of plates would greatly enhance the price, without advancing or
adding to the value of the work.
If, however, a second edition should be required, various figures
in illustration of particular subjects may be added, either with
a distinct explanatory chapter, or a reference from the articles
themselves, with the necessary explanation, to the figures
respectively.
It would require at least twenty-five plates to include all the
figures we originally intended to have introduced.
Before concluding this introduction, it remains for us to remark,
that, in forming this work, we consulted a variety of authors, but
with little advantage, except some French works, which we shall
notice. Chaptal (_Chimie Appliqué aux Arts_;) Bigot (_Artifice de
Guerre_;) Morel (_Feux d'Artifice_;) Thenard (_Traité de Chimie_;)
Ruggeri (_Pyrotechnie Militaire_;) MM. Bottée and Riffault (_Traité
de L'Art de Fabriqué la Poudre à canon_;) Peyre (_Le Mouvement
Igné_;) Biot (_Traité de Physique_, _Recherches Experimentales et
Mathématique_, _sur les mouvement des Molecules de la Lumiere_,
_&c._;) M. Duloc (_Theorie Nouvelle sur le Mechanisme de
l'Artillerie_;) the _Dictionnaire de l'Industrie_; the _Dictionnaire
Encyclopedique des Arts et Metiers Mecaniques_, article _Art de
L'Artificier_; _Œuvre Militaire_; _Archives des Découvertes_;
_Système des Connoissances Chimiques par A. F. Fourcroy_;
_Aide-Mémoire a l'usage des officiers d'Artillerie de France_.
We examined various authors in English; and with regard to the origin
of inventions, we found the learned, and valuable work of professor
Beckman (_History of Inventions_) very useful, and likewise James's
_Military Dictionary_. To the _Encyclopedia Britannica_, we are
indebted for many interesting facts, and some extracts on fire-works
for exhibition.
On the subject of mining, we consulted the _Treatise on mines for the
use of the Royal Military Academy_, by Landmann.
We deem it necessary to observe, that, in collecting our formulæ for
military fire-works, although we have sometimes extracted from the
Strasbourg _Memoir_, the _Bombardier and Pocket Gunner_, and the
_Military Dictionary_ of Duane and James, we have generally followed
Bigot; as the formulæ which he gives for the preparation of Military
fire-works have been approved by the French government; and where
any thing of importance occurred in Ruggeri, we have, for the same
reason, extracted such formulæ from that author.
As respects the turtle, torpedo, and catamarin, submarine machines,
it appears that Bushnel (_Trans. Am. Phil. Soc._) claims the
originality of the discovery from the date of his invention,
although similar contrivances had long ago been suggested. Fulton's
improvements, in the torpedo, are deserving of particular attention;
but it is plain, that the Catamarin of the English is the same in
principle and application as Fulton's torpedo, and that Fulton
deserves the merit of it. Congreve, if we believe Ruggeri, was not
the inventor of the rocket, which bears his name; for, according
to him, it was invented about the year 1798 by a naval officer at
Bourdeaux. It is certain, however, it was neither much known, nor
used before the attack on Copenhagen.
It is certain that the present incendiary fire-stone was taken
from the recipe for fire-rain contained in the military work
of Cassimir Siemienowicz, or that the fire-rain gave rise to a
similar preparation. The idea of the _pyrophore_, mentioned in the
_Archives des Découvertes_, must have originated from the use of the
powder-barrel, and of similar means of defence. We might enumerate
many other inventions, which owe their origin in the same way.
A SYSTEM
OF
PYROTECHNY.
CHAPTER I.
PYROTECHNY IN GENERAL.
_Sec. I. Definition of Pyrotechny._
Pyrotechny is defined the doctrine of artificial fire-works, whether
for war or exhibition, and is derived from the Greek, πυρ _fire_, and
τεχνη _art_. In a more general sense, it comprehends the structure
and use of fire-arms, and the science which teaches the management
and application of fire in several operations.
_Sec. II. General theory of Pyrotechny._
In the composition of artificial fire, various substances are
employed, having different properties, and designed to produce
certain effects characterised by particular phenomena. These
substances are either inflammable, or support the combustion of
inflammable bodies. As pyrotechnical mixtures are differently formed,
and of various substances, the effects are also modified, although
combustion, under some shape always takes place.
Combustion is either modified, retarded, or accelerated; and
in consequence of the presence of certain substances, different
appearances are given to flame.
The conditions necessary for combustion are, the presence of a
combustible substance, of a supporter of combustion, and a certain
temperature. Thus, charcoal when raised to the temperature of 800° in
the open air, takes fire. This elevation of temperature enables it
to act chemically on the oxygen gas of the atmosphere; the latter,
as it comes in contact, being decomposed. Now, as oxygen gas is a
combination of oxygen and caloric, the caloric being in a latent
state, the charcoal unites with the oxygen, and the phenomena of
combustion ensue; that is, an evolution of _heat_ and _light_.
The caloric of the decomposed gas is given out in a free state,
and, according to the theory of Dr. Thomson, (_Thomson's System of
Chemistry_, vol. i.) the light proceeds from the burning body. We
have then an instance of combustion, in which there is a combustible,
a supporter of combustion, and an elevated temperature. The old
theory of combustion, called the _Stahlian_ theory, which presupposes
an element called phlogiston, or a principle of fire, to exist in all
bodies under some modification, would explain these effects by merely
supposing, that combustion was nothing more than a disengagement of
phlogiston; and that when a body had lost its inflammable principle,
(as a metal, when oxidized), it became dephlogisticated. But,
as it proved that phlogiston is a hypothetical element, and the
anti-phlogistic doctrine clearly shows, that combustion is no other
than a process which unites the supporter with the combustible,
forming new products; it follows, that, in all changes of the kind,
the same reasoning will apply, and the same principle be tenable.
The products of combustion depend on the nature of the substance
burnt, and the supporter employed. Thus, in the instance just
mentioned, the charcoal, by its union with oxygen, is changed into
carbonic acid, which takes the gaseous state. We say then, that
carbonic acid is the product of the combustion of charcoal, or,
chemically speaking, of carbon. As resins, oil, &c. contain hydrogen,
as well as carbon, the products in such cases would be water, as well
as carbonic acid.
The chemical effects, therefore, which we consider in fire-works,
forming the basis on which a theory of sundry phenomena may be
formed, are no other than the result of the action of one body
on another, according to the laws which govern such action, and
the consequent operation of chemical combination. Combustion, in
fire-works, may be considered a primary agent in _all effects_ which
characterise artificial fire.
The second change, with respect to the appearance of the flame,
the formation of stars, serpents, rain, &c. terms used in the
art, is owing either to new chemical changes which the substances
undergo, or to the decomposition of the products themselves. These
effects, it is obvious, must be governed by the circumstances,
under which the mixtures are made. Saltpetre, for instance, is the
basis of fire-works, whether used in a separate state, or employed
in mixture with charcoal and sulphur, as in gun-powder; and, from
its composition, is adapted to all the purposes of the art, because
it yields its oxygen very readily to all inflammable bodies. In
consequence of the decomposition, it undergoes at an elevated
temperature, when brought in contact with charcoal, sulphur, &c. and
various substances which contain carbon, as pitch, rosin, turpentine,
tallow, copal, and amber, combustion results, and, according to
circumstances, is more or less rapid, and the flame also more or less
brilliant.
When charcoal, in the state of ignition, is brought in contact with
nitre, a deflagration takes place, because, at the temperature of
ignition, it has the property of decomposing the nitric acid of the
nitre; and as this process unites the carbon with the oxygen, in
the proportion necessary to constitute carbonic acid, this acid is
accordingly produced. When, therefore, we inflame a mixture of nitre,
charcoal, and sulphur, or gun-powder, the whole or greater part
disappears; and if we were to collect in a pneumatic apparatus, the
products of the combustion, it would be found, that they are nearly
altogether gaseous, and composed, as we shall speak hereafter, of
sundry elastic aëriform fluids. This decomposition, the immediate
effect of the charcoal on the nitric acid of the nitre, is the same
as in the preceding instance, for carbonic acid gas is formed in both
cases. We have then another instance of combustion, where a number
of substances are concerned, and therefore, the products must be
numerous.
We notice this subject more particularly, since, as in the different
fire-works, nitre and inflammable bodies are used in different
proportions, the result is always affected by the same laws of
chemical decomposition; for the same substances, placed under similar
circumstances of proportion, mixture, &c. afford the like results.
If carbon alone be employed, carbonic acid gas is the result; if
oil, tallow, rosin, or turpentine be used, we have then, as we had
occasion to remark, water, as well as carbonic acid, by reason of
the union of the hydrogen, which forms one of their constituent
parts, with a part of the oxygen of the nitric acid.
Again, in a composition of mealed powder, rosin and sulphur, with
or without the addition of saw dust, we infer, from the composition
of the ingredients and the chemical action which subsequently takes
place, that the products of combustion would be carbonic acid gas,
sulphurous acid gas, water, sulphuretted hydrogen, and probably
azotic, and nitric oxide gases. If the filings of steel, brass,
zinc, or copper, enter into the composition, besides the products
above-mentioned, there would be either an oxide of iron, an oxide
of zinc, or, an oxide of copper, according as one or other of these
metals are employed.
Copper, in fire-works, has the effect of communicating a green
colour to the flame. M. Homberg, (_Collection Acad._) observes, that
the green colour in such cases is owing to the _dissolution_ of
the metal, which in fact is nothing more than the _effect_ of its
oxidizement.
The various compositions for brilliant fire, as the Chinese fire, owe
their peculiar character to pulverised cast iron, and commonly to
steel and iron filings. Now the effects in these cases are the same;
for the same oxidizement ensues, more or less rapidly, which in fact
distinguishes the kinds of brilliant fire. That of the Chinese is the
most perfect, and next is the composition made with steel filings. It
will be seen, however, that compositions generally are governed, in
their respective appearances when inflamed, by the purity, as well as
the proportion of other substances, which enter into them; and hence
much of their effect depends on collateral circumstances, which we
purpose to consider when we treat of the compositions individually.
That the light of certain burning bodies may be increased, is evident
from these facts; and experiment has shown, that the intensity of
the light of burning sulphur, hydrogen, carbonic oxide, &c. is
increased by throwing into them, zinc, or its oxide, iron, and other
metals, or by placing in them very fine amianthus or metallic gauze.
Protochloride of copper burns with a dense red light, tinged with
green and blue towards the edges. If the hydrogen of the oil acts in
separating the chlorine from the copper, and the reduced copper is
ignited by the charcoal, this appearance must necessarily ensue.
When solid matter is the product of combustion, as in the burning
of phosphorus, zinc, iron, &c. the flame is remarked to be more
intense. Flame may be modified under other circumstances, as we will
have occasion to mention hereafter. When, for instance, a wire-gauze
safety-lamp is made to burn in a very explosive mixture of coal gas
and air, the light is very feeble and of a pale colour; but when a
current of coal gas is burnt in atmospheric air, the combustion is
rapid and the flame brilliant.
Dr. Ure thinks it probable, (_Dictionary of Chemistry_, article
combustion,) that, when the colour of the flame is changed by the
introduction of incombustible compounds, the effect depends on the
production, and subsequent ignition or combustion of inflammable
matter from them. Thus he infers, that the rose-coloured light given
to flame by the compounds of strontium and calcium, and the yellow
colour given by those of barium, and the green by those of boron, may
depend upon a temporary production of these bases, by the inflammable
matter of the flame. It is inferred also, as a probable conclusion,
that the heat of flames may be actually diminished by increasing
their light, (at least the heat communicable to other matter), and
_vice versa_; because, in the most intense heat, as in the compound
blow pipe, or in Newman's blow pipe apparatus, in which a mixture of
oxygen and hydrogen gases is compressed, the flame, although hardly
visible in bright day light, instantly fuses the most refractory
bodies; but the light of solid bodies ignited in it, is so vivid as
to be painful to the eye.
Some curious facts with regard to flame, in connection with
electricity, are given by Brande in the Phil. Trans. for 1814. He
supposes that some chemical bodies are naturally in the resinous,
and others in the positive electrical state. He supposes also,
as a consequence, that the positive flame will be attracted, and
neutralize the negative polarity, while the negative flame will
operate a similar change by inducing an equilibrium at the positive
pole. Thus he found, that certain flames were attracted by the
positive ball of an electrical apparatus, and others attracted by the
negative ball. The flame of sulphur and phosphorus is attracted by
the positive pole, and the flame of camphor, resins, and hydrogen by
the negative pole.
In relation to the production of flame, we may observe, that, as
sundry solid and fluid substances are inflammable, the products of
combustion depend on the composition of the substance made use of,
and the condition under which it is burnt. As to gaseous substances
that are inflammable, the base of some gases, we may remark, as
carbon and hydrogen, unite in the process of combustion with the
base of other gases, (as oxygen;) and in other instances, the _gas_
itself takes fire, and exhibits the phenomena of flame. Now carbonic
acid gas extinguishes flame, although its base is inflammable; but
hydrogen, as well as hydrogen gas, is inflammable, and when burnt in
oxygen gas or atmospheric air produces water, which also extinguishes
the flame of burning bodies.
As we will have occasion to notice a variety of aëriform fluids,
especially when we treat of the aëriform products of fired
gun-powder, a few remarks on this head may be useful at this time.
By the combustion of bodies, substances are generated that are
either gaseous or solid, whence arises the variety of products. Of
aëriform fluids, some are coloured, as nitrous acid vapour, (nitrous
gas and oxygen), chlorine, and the protoxide and deutoxide of
chlorine. The first is red, the rest yellowish-green, or yellowish.
Some relight a taper, provided the wick remain ignited, as oxygen
gas, protoxide of azote, and the oxides of chlorine. Others produce
_white vapours_ in the air, as muriatic acid, fluoboric, fluosilicic,
and hydriodic. The inflammable gases, which take fire in the air
by contact of the lighted taper, are hydrogen, hydroguret, and
bihydroguret of carbon, carbonic oxide, prussine or cyanogen,
called also carburet of azote, and phosphuretted, sulphuretted,
arsenuretted, telluretted, and potassuretted hydrogen. Other gases
are acid, and redden litmus, which, for that reason, are called acid
gases, such as nitrous, sulphurous, muriatic, fluoboric, hydriodic,
fluosilicic, chlorocarbonic, and carbonic acids; the oxides of
chlorine, sulphuretted hydrogen, telluretted hydrogen, and carburet
of azote. Some gases are destitute of smell, as oxygen, azote
and its protoxide, and carbonic acid; while others have a strong
and characteristic odour, as ammoniacal gas. Some gases are very
soluble in water, and others but slightly soluble, such as fluoric,
fluosilicic, carbonic, sulphurous, and muriatic acids, and ammoniacal
gas. Alkaline solutions absorb some gases, as nitrous, sulphurous,
muriatic, fluoboric, carbonic, hydriodic, fluosilicic, chlorine,
chlorocarbonic, and the two oxides of chlorine, sulphuretted
hydrogen, telluretted hydrogen, and ammonia. Alkaline gases are
ammonia, and potassuretted hydrogen.
The character of gases is well defined. The compound gas of
phosphorus and hydrogen takes fire spontaneously in the atmosphere,
burning with a brilliant white flame; but there is another gas formed
of the same substances, that does not inflame spontaneously, but is
inflammable, called subphosphuretted hydrogen. This gas has a strong
smell of garlic or phosphorus, and is luminous in the dark. It may
be this peculiar combination, which gives rise to the _ignes fatui_;
but the permanent ignes fatui, observed in volcanic countries, are
said to be the slow combustion of sulphur, forming sulphurous acid
gas. Sir H. Davy found, that phosphuretted hydrogen produced a flash
of light when admitted into the best vacuum that could be made by an
excellent pump of Nairn's construction.
Naphtha in contact with red hot iron glows with a lambent flame
at a rarefaction of thirty times, though its flame ceases at an
atmospheric rarefaction of six. Camphor ceases to burn in an air
rarefied six times, but, in a glass tube which becomes ignited,
the flame of camphor exists under ninefold rarefaction; whereas
phosphorus, according to the experiments of Van Marum, will burn,
although the atmosphere be rarefied sixty times. Hydrogen gas will
burn in a rarefied air, when it is four or five times less than the
pressure of the atmosphere, and its flame be extinguished, when the
pressure is between seven and eight times less; from which it is
inferred, that the flame is extinguished in rarefied atmospheres,
only when the heat it produces is insufficient to keep up the
combustion. Olefiant gas (hydroguret of carbon) ceased to burn in an
atmosphere, where its pressure was diminished between ten and eleven
times. The flames of alcohol and of wax taper were extinguished in
an atmosphere, where pressure was five or six times less without
the wire of platinum, and seven or eight times less when the wire
was kept in the flame. See _Flameless Lamp_. Several interesting
conclusions may be drawn from these facts, which, to enumerate, would
lead us beyond our design. It will be sufficient, therefore, to
add, that although a supporter of combustion is necessary for that
process, and flame may be differently modified, yet combustion ceases
if the pressure of the atmosphere be diminished in certain ratios, as
already noticed.
Besides nitre, other saline substances which contain oxygen feebly
combined, have been used for the same purpose. Some years ago, it
was proposed to substitute the hyper-oxymuriate, now called chlorate
of potassa, for nitre in the formation of gun-powder. As chlorate
of potassa, when mixed with sulphur, &c. produces combustion by
percussion, or by the contact of fire, this effect is attributed to
the same cause,--the separation of oxygen, not from azote, but from
the chlorine of the chloric acid, Hence, when that salt is used in
fire-works, the result of the combustion is similar to that in which
nitre is employed; at least as regards the union of the oxygen with
the elementary principles of the inflammable body. On this subject,
we shall make some remarks hereafter. Nitrate of soda, a salt which
contains nitric acid, and similar to saltpetre in that particular,
has been recommended also for fire-works. It has, however, several
objections. Our object in noticing it at this time is to remark,
that, when it is so employed, its effect is the same as nitrate of
potassa, or saltpetre, by furnishing oxygen as the supporter of
combustion. See _Nitrate of Soda_.
We are of opinion, that many of the nitrates might be advantageously
employed in the manufacture of fire-works. Some, as nitrate of
strontian, communicate a red colour to flame, as the flame of
alcohol. Nitrate of lime also might be used.
All nitrates, as well as the different hyperoxymuriates, or
chlorates, contain oxygen as an essential ingredient in the acid of
their respective salts, which is readily given up to inflammable
substances.
When nitrates are employed for fire-works, they should be free from
moisture, or water of crystallization, unless otherwise required.
The presence of water may, in many cases, prove injurious to the
composition; and, consequently, the effect in those instances, may be
influenced by this circumstance. The composition of nitric acid, and
the action of carbon in the decomposition of the nitrates, or salts
formed by the union of nitric acid with sundry bases, will claim our
attention in the article on gun-powder.
With respect to the production of colours, some remarks on this
subject may be here added.
Speaking of colours, Haüy (_Elementary Treatise of Natural
Philosophy_, trans. ii. p. 253.) takes into view their formation
according to the Newtonian doctrine; and in a note by the translator,
several instances are given of the change of colour by oxidizement
and other processes. Iron when exposed to heat in contact with
atmospheric air gradually absorbs oxygen, and changes its colour.
The colours produced depend entirely on the quantity of oxygen, and
on the absorption of some of the rays of light, and the reflection
of others. See _Iron_. The tempering of steel instruments depends on
this property, and also the blueing of sword blades, and many similar
operations. The first impression of fire usually developes a blue
colour; a second degree produces a yellow; and, if the oxidizement
augments, the iron becomes red. The major part of the metals present
similar phenomena.
In vegetables, the blue colour is formed by fermentation; and many of
these colours are susceptible of passing to red by a greater quantity
of oxygen, as they depend on the absorption of oxygen. It is thus
that the green fecula of indigo becomes blue; turnsol, red by air and
acids; and the protoferrocyanate of iron, blue when exposed to the
air.
When meat putrefies, the first degree of oxygenation decides the blue
colour; the red soon succeeds as the process goes on. It would seem
that the maximum of oxidation determines the reflection of rays of
every kind, in the same proportions as subsist in solar light, of
which we have many instances in combustion.
The flame of burning bodies exhibits the same phenomena. It is blue
when the combination of oxygen is slow; red when it is stronger, and
white when the oxygenation is complete.
These facts lead to the conclusion, that the combination of oxygen,
and its proportions, give birth in bodies to the property of
reflecting corresponding rays of light; but, since the combination
of oxygen in different proportions ought to change the thickness
and density of the component laminæ, and, consequently, to produce
variations in the colours, this doctrine is not easily reconciled
with the received theory.
By considering the temperature necessary to inflame different bodies;
the nature of flame, and the relation between light and heat, which
compose it; the caloric disengaged in a free state during the
combustion of bodies, and the causes, which modify the appearance
of flame,--we may be enabled to account for the phenomena already
noticed. Thus, phosphorus at 150°, and sulphur at 550°, are said
to take fire, and two acid products are formed; at 800°, hydrogen
gas explodes with oxygen, and produces water; and, according to
Ure's view, the flame of combustible bodies may in all cases be
considered as the combustion of an _explosive mixture_ of inflammable
gas, or vapour, with air; and as to the change of quiescent into
distributable heat, and the causes that modify combustion and flame,
the facts on these heads are numerous and very important.
_Sec. III. Remarks on the Nature of particular Compositions._
The _spur fire_, which was invented by the Chinese, but brought to
perfection in Europe, is remarkably beautiful when employed in some
particular parts of fire-works. This fire was so named from the
effect it produces, that of forming scintillations, resembling a
shower, or drops of rain, or the rowel of a spur. The _artificial
flower pot_ is formed of this fire. The _stars_ and _pinks_, which
it produces, are said to be brilliant. The composition of spur
fire being saltpetre, lampblack, and sulphur, in the proportions
we shall give hereafter, is similar in fact to that of gunpowder;
for the lampblack acts in the same manner as common charcoal. As
the lampblack, however, is extremely fine, and of a purer quality,
its action on that account may be more powerful. While one portion
of it decomposes the nitric acid of the nitre, with the oxygen of
which it forms carbonic acid; another portion is thrown off in
actual combustion, which puts on the appearance we have mentioned.
Lampblack, it is to be observed, is a very impalpable powder, and
takes fire with more facility than pulverised charcoal.
The lampblack, therefore, is consumed both by the oxygen of the
nitre, and the oxygen gas furnished by the atmospheric air. With
respect to the sulphur, it facilitates the combustion, as it is
more readily inflamed, and it forms in the process of combustion,
sulphurous acid gas. Spur fire has been improved by the addition of
steel filings: They produce very brilliant scintillations, in the
combustion of which, oxide of iron is formed.
With respect to the composition of rockets, the materials of which
are united in different proportions, we will remark at this time,
that as mealed powder, saltpetre, and charcoal constitute their
principal ingredients, the chemical effect is similar to that we
have stated. The combustion of such mixtures is attributed to the
same cause; for whether we consider the composition of gunpowder, or
the extra addition of saltpetre and charcoal, or the substitution
of nitre for the gunpowder, the action must be the same, and
therefore the products of combustion, similar. The action, however,
as the effect evidently shows, is affected by the proportion of
the substances employed, and by other circumstances which we shall
notice hereafter. The different appearances, therefore, are owing
entirely to the composition, as in _rocket stars_, _rains_, _gerbes_,
_tourbillons_, _&c._
It may appear surprising, that the combustion of gunpowder with
other substances, previously well rammed in cases, as in the rocket,
will give to the case a _momentum_ of great velocity and force.
This motion is regulated by the _balance_ of the rocket; and its
_power_ depends upon the size of the case, and the compactness of
the composition. There is nothing new, however, in the fact; for it
is perfectly familiar with every one, if we consider the recoil of
a gun when fired, the powder having a resistance to overcome, as the
ball, that the explosive effect of gunpowder is equal, and that the
gases produced impel on all sides. Now the effect of a ball is as
the difference of its weight with the weight of the gun; while the
one being so much lighter is propelled forward with great celerity,
and with a corresponding projectile force, the other suffers but
little motion, which we term the recoil. The combustion of the
materials, of which a rocket is composed, in a case, and in many
fire-works where the cases are arranged on wheels, &c. which act on
the rocket-principle, produces in like manner a force proportionate
to the quantity of the material employed, and the manner it is driven
in the case. The force in such instances is given to the rocket by
the combustible substances; and the rocket itself when free, will
ascend, or move in the direction required; or if small cases are
fixed on wheels, which move on an axis, they communicate motion, as
in the single vertical wheels, horizontal wheels, plural wheels, and
the like, and may then be considered a moving power. That rockets
are used as a missile weapon is well known. They were employed by
the native troops of India against the British during the siege of
Seringapatam in 1799. Mr. Congreve, the inventor of the _war-rocket_
which bears his name, may have received his first idea of using
rockets from this circumstance. This rocket will be described
hereafter. The projectile force of the rocket is well calculated
for the conveyance of case shot to great distances; because, as it
proceeds, its velocity is accelerated instead of being retarded, as
happens with every other projectile, while the average velocity of
the shell is greater than that of the rocket only in the ratio of 9
to 8. The basis of this increase of power in the flight of rockets,
induced Congreve to make a number of experiments, which resulted in
their improvement, so far as they may be used of various calibres,
either for explosion or conflagration, and armed both with shells and
case shot. It may be sufficient to remark, that the 32 pr. rocket
carcass, which has been used in bombardment, will range 3000 yards
with the same quantity of combustible matter as that contained in the
ten inch spherical carcass.
M. de Buffon, (_Mémoires de l'Académie_, 1740,) wrote an ingenious
essay on sky rockets, in which he states the appendages which may be
put to them.
If we inquire into the cause of the ascension of rockets, it will
appear, that this apparently extraordinary effect, as we have
already remarked, is owing to the decomposition, and the consequent
production and disengagement of a large quantity of gaseous fluid
and caloric. The impelling power, as in the large Congreve rocket,
of which we had occasion to speak, is regulated in proportion to its
size, and the accuracy with which the materials have been driven.
The manner in which the flame, and, consequently, the gases are
expelled from the orifice of a rocket, resembles the operation of an
æolipile, which throws out the vapour of water, and sets in motion
the air in its vicinity. As the more flexible must yield to the more
solid body, so, in this respect, the gases produced are repelled by
the air in contact with the orifice of the rocket. Thus it follows,
that the rocket _displaces_ a volume of air of a much greater weight
than itself. The rocket then has upon the air, reasoning _a priori_,
the same effect as the oars of a boat have upon water; and hence,
the greater the volume of fire from the rocket, the greater is
its velocity and ascent. The impelling force also increases as it
consumes, being a uniformly accelerated motion.
It also appears, that a rocket sent in an horizontal direction will
not pass over so great a distance, as when its motion is vertical;
for, a rocket, directed in a line parallel to the horizon, passes
through a medium of equal density, but if directed perpendicular to
the horizon, from the moment it leaves the ground till it arrives at
its greatest height, it penetrates and passes through an atmosphere
whose density is continually decreasing, and consequently its
impelling force meets with less resistance. But when we consider the
increase of the force of the rocket, there is no comparison between
that force, and the diminution of the density of the air.
From these premises it follows, that the ascension of rockets of
all kinds is governed by one principle, namely, the disengagement
of gaseous fluids and caloric, which displacing an equal volume of
atmospheric air, operates by mutual contact.
Since, however, the air is heavier than the gases produced by the
rocket, as the latter are greatly expanded, it is evident, that the
gases will ascend; their specific gravity at the time of dilatation
being less than that of the air.
The gases proceeding from the interior of the rocket, act therefore
upon the air in the immediate vicinity of the orifice, and the rocket
is consequently propelled, the stick guiding it in the direction
given to it. If it were not for the rocket-stick or balance, its
direction would be neither regular nor certain. Considering then,
that, by the rocket-stick, the centre of gravity is changed from
the rocket itself to the stick, the motion is regulated in its
perpendicular flight by the stick. The rocket-stick must be always of
a proportionate length and weight to the rocket.
The motion given to rockets is always to be considered, for this
depends upon the direction at first imparted; but the force of
ascension is regulated by the size, and other circumstances which we
have mentioned.
Assuming the principle of constant force acting upon the rocket, its
velocity will increase with the time, and will be as the squares of
the time, according to the principles of uniform accelerated motion;
but if the force varies from uniformity, then the velocity and spaces
will proportionably vary.
As action and re-action must be equal, the repulsion produced by the
action of the gases upon the air is equal to the force impelling the
rocket. The constant action produces equal acceleration of the motion.
On the subject of the condensation and dilatation of air, and the
different pressures at a mean temperature, which is more or less
connected with this inquiry, the reader may consult with advantage,
the work of Mr. Biot, (_Traité de Physique_, &c. tome i, p. 110,
and 141.) The conclusions of Mr. Robins on the gaseous products of
gunpowder, and the elasticity of those products, may be seen by
referring to the article on _gunpowder_.
It must be confessed, that the theory of rockets differs in many
essential particulars from that of the usual projectiles; for
the motion of rockets is more complicated than that of common
projectiles, and is described to partake of all the anomalies that
attend the accelerated motion arising from the rocket composition,
and the uniform motion of the rocket-case, after the composition is
expended. It is a fact, which appears to be established, that little
or no advantage has yet been gained from the experiments that have
been made with cannon, even where the angle of elevation, and the
initial velocity of the ball were both accurately known. It seems
totally useless to look for mathematical investigations, with respect
to determining the ranges, &c. of military rockets; because, if we
could determine, with the greatest accuracy, the point, position,
and velocity of the rocket, at the moment when the composition was
expended, the remaining part of its track would still be subject
to all the inequalities attending on common projectiles. During
the burning of the rocket, however, its motion might, by a series
of experiments, be reduced to precise rules. As the principles of
gunnery, or rather of projectiles, involve a number of collateral
circumstances, such as the exact momentum of any given ball when
projected with a given velocity, and from a given distance, the
subject is still not fully settled; but they are so far conclusive,
that the resistance of the air to the same ball is as some function
of the velocity. The remarks of Dr. Hutton on this head would be too
lengthy. A rocket, however, is very different. The very medium, in
this case, is the principal agent in producing the motion; and being
enabled to ascertain all the successive energies of the propelling
power, and the resisting force, we may thus far determine correctly.
It is suggested, that a rocket fixed to the ballistic pendulum would
determine its whole energy; but, in order to make the experiment more
perfect, it is proposed to attach it to a wheel, or revolving body,
and then to measure its successive energies by the motion of some
weight attached to the revolving axis of the machine. It is worthy of
remark, that it is impossible to accommodate or determine the motion
of rockets by other projectiles; and, therefore, to ascertain their
momentum, such a contrivance would be eminently useful.
Mr. Moore of the Royal Military Academy, Great Britain, (_Treatise
on the motion and flight of rockets_,) who seems to have adopted the
hypothesis of Dr. Desaguliers, respecting the momentum of the ignited
composition, has given a variety of problems relative to the motion
and flight of rockets in non-resisting mediums, some of which we
purpose to notice.
Mariotte and Desaguliers have given two distinct theories of the
motion of rockets. The latter ascribes their motion to the momentum
of combustion, and the former to the elastic nature of the gaseous
fluid, generated by the combustion, and the resistance of air. The
observations of Desaguliers are the following: "Conceive the rocket
to have no vent at the choke, and to be set on fire, the consequence
will be, either that the rocket will burst in the weakest place,
or if all the parts be equally strong, and be able to sustain the
impulse of the flame, the rocket would burn out immoveable. Now, as
the force of the flame is equable, suppose its action downwards, or
that upwards, to lift 40 pounds; as these forces are equal, but their
directions contrary, they will destroy each other's action. Imagine
then the rocket opened at the choke; by this means, the action of the
flame downwards is taken away, and there remains a force equal to
forty pounds, acting upwards, to carry up the rocket and stick." This
theory, however ingenious, is not altogether true; for it is asserted
on the contrary, that the action of the flame or gas within the
rocket, when closed, as supposed above, is conceived to arise wholly
from the elastic nature of the gas, and the reaction it experiences
against the ends and sides of the rocket-case; the whole of which
ceases as soon as a free vent is given to the flame; and, therefore,
if a rocket could be fixed in a vacuum, as the flame would, in that
case, experience no resistance, there would be no reaction, and
consequently, no motion would ensue. Some experiments, analogous to
this position, have been made. We may merely add, with respect to
Mariotte's theory, that he attributes the motion of the rocket to
the resistance and reaction of the air, in consequence of which the
propelling force will decrease as the velocity increases, owing to
the partial vacuum left behind the rocket in its flight; so that the
correct solution of the problem necessarily involves the integration
of partial differences of the highest orders.
We may remark also, from the premises already established, that the
first motion of the rocket, like all other motions not produced by a
great momentary impulse, is slow; and before the stick is clear of
the flame, gravity has been acting upon the rocket, and depressed it
below its natural position, while the stick is prevented from being
equally depressed, by the top of the frame; so that the angle of
projection is in fact considerably less than the angle of the frame,
or slope of the rocket's first position. In consequence of this, the
rocket has the appearance of falling the moment after projection;
and, for this reason also, the angle for producing the greatest
range of a rocket exceeds very considerably that which gives the
extreme range of a shell projected from a mortar. There are various
propositions given by Mr. Moore respecting rockets, but to give the
calculus, &c. would take up more room than we could appropriate to
this abstract question. The nature of these propositions, however,
may be given in a few words, _viz_: The strength or force of the gas
from the inflamed composition of a rocket being given, as also the
weight and quantity of the composition, the time of its burning, and
the weight and dimensions of the case and stick, to find the height
to which it will ascend, when projected perpendicularly upwards.
After making the necessary calculation, he concludes by observing,
that, having determined the height of the rocket, and its velocity,
when the composition is just consumed, it follows that its whole
height may be determined in the usual manner by the known formula,
for the ascent and descent of heavy bodies. Another proposition is
that of determining the path of a rocket near the earth's surface,
neglecting the resistance of the air; and among others, for finding
the horizontal range of a rocket, the angle of elevation, and the
time the composition is on fire, being given.
The observations of Mr. Peyre, (_Le Mouvement Igné_,) are confined
principally to the effects of gunpowder; and although applied to the
use of gunpowder, and the theory of its explosive effects, yet there
is nothing in immediate relation with this subject. The generation
of gaseous fluid, and its impelling power, and the consequent recoil
of pieces, predicated in fact on the ingenious experiments and
conclusions of Mr. Robins, may furnish some data on this head. But
the principles of accelerated motion, on which the effective power of
war-rockets depends, this accelerated motion being no other than the
acquired velocity of their recoil, necessarily involves a question of
a different kind from that of common projectiles.
The _caduceus_ rocket has not much more than half the power of
ascension as the single rockets; because, being composed of
two rockets placed at an angle of 90 degrees, with the usual
counterpoise, (the stick), it forms in its flight a serpentine motion
resembling two spiral lines, or double worm; and although by reason
of the stick it ascends vertically, yet the great resistance it meets
with from the air, in consequence of this motion, causes its flight
to be considerably retarded.
On the contrary, when rockets are fixed one on the top of another,
called _towering rockets_, their effect is not at all diminished;
for they experience no additional resistance, as the small rocket is
placed in the head of the large one; and when the latter arrives at
the maximum of elevation, it communicates fire to the former, which
then rises as far beyond the first, if not higher, in consequence of
the pressure of the atmosphere being less, as it would, if discharged
by itself on the ground. Sky rockets, however, which are merely
placed on one stick, do not, unless so required, act in this manner.
Although two, three, or more, may be so arranged, yet the intention
is nothing more than to combine their effect, so that their tails may
appear as one stream of fire. Nevertheless, they may be so arranged,
as that when one is consumed, another may take its place, and produce
a new volume of fire, and, in this case, they would mount to a great
height.
_Tourbillons_, usually called the common or table _tourbillons_,
which receive their name from the whirling motion they take in
their flight, produce also, by the arrangement of their cases, and
the cross stick which serves as a balance, a horizontal and rotary
motion; and while one part of the fire serves to elevate them,
another part, issuing in a horizontal direction, but at opposite
sides and extremities, gives to the tourbillon a wheeling motion. The
mosaic tourbillons are of a different kind, and intended for another
effect. Tourbillons of this kind preserve a regular and constant
motion.
The _mosaic candle_ owes its effect, in a great measure, to the
rocket composition. Using alternately, composition, meal-powder,
and a star, ramming the composition sufficiently, but not so as to
break the stars, a case is formed, the effect of which is brilliant
and striking. Besides the rapid combustion of the composition, the
stars, when the fire comes to the meal-powder, are thrown out by it
in succession, and to the height of one hundred and more feet. We
have also, in this instance, the effect of the rocket composition,
and that of gunpowder; the last of which, acting in the case in the
same manner as powder in a musket on a ball, throws the stars to a
great height. Hence the _effect_ is varied according to the manner
of loading the case; and by employing alternately the substances
we have mentioned, the effects follow in regular succession. The
use of gunpowder in this manner, is strikingly shown in many other
fire-works. When, for instance, stars, serpents, &c. forming the
furniture of a rocket, are to be dispersed, gunpowder is put in the
head or conical cap of the rocket, and fire is communicated to it at
the moment the rocket has arrived at its extreme elevation. In the
bursting of paper shells, the same effect ensues, and the different
substances contained in the shell are dispersed in every direction.
Balloons are nothing more than shells made either of paper, or
wood turned hollow. These balloons are discharged from mortars,
or fire-pots, sometimes called pots of ordnance. They are merely
cylinders of various diameters, made of paper and very thick, or
of metal, and are furnished at their bottom with a conical cavity
lined with copper, designed to hold the charge of powder. When the
balloon is filled, (see _Balloons_), it is introduced into the
mortar over the charge, and being furnished with a fuse as in other
shells, takes fire the moment the powder is inflamed. According
to the quantity of powder made use of, so will be the height of
ascension. By determining the ascension, and the time required for
the fuse to burn, and communicate fire to the shell, we may fix the
precise moment for its explosion. The powder contained in the shell
is sufficient only to burst it, and disperse its contents. (See
_Mortars_, _Fire-pots_, and _pots of Aigrette_.)
A balloon will contain more stars, serpents, &c. than the head of an
ordinary rocket, and the effect which they produce, must of course
be more striking. The Congreve rocket, calculated as it is to convey
carcass composition, balls, grenades, &c. if furnished with stars,
crackers, &c. would produce an effect equal, if not superior to the
balloon.
We remarked, that, in common sky rockets, the charges consist of a
mixture of gunpowder, saltpetre, and charcoal, with occasionally
other additions, as steel-filings. _Rocket-stars_, on the contrary,
are usually formed of mealed powder, saltpetre, sulphur, and
sometimes other substances according to the colour of the flame
required. Thus, for the _white star_, composition oil of spike, (a
preparation of Barbadoes tar, and spirit of turpentine), and camphor
are employed; the camphor giving to the flame a white appearance. The
_blue stars_ owe their colour to sulphur, which is in the proportion
of one to four of the meal-powder; the _variegated stars_ have the
same materials, with sulphur vivum, and camphor; and the _brilliant
stars_, _common stars_, and a variety of others, we shall mention
in their proper places, are all formed by the addition of sundry
substances.
The variety of _rains_, as _gold rain_, _silver rain_, &c. are
differently prepared. Besides saltpetre, meal-powder, and sulphur,
gold rain contains in its composition the filings of brass, saw-dust,
and pulverized glass. In this instance, the saw-dust communicates
colour, while the brass and the glass are thrown out, the former
partly consumed, and the latter partially fused by the intense heat.
The same effect may be produced by meal-powder, saltpetre, and
charcoal, or saltpetre, sulphur, antimony, brass filings, saw-dust,
and pulverized glass. Here the antimony, as well as the brass,
communicates the golden colour. (_See antimony._) Silver rain is
generally formed of saltpetre, sulphur, meal-powder, antimony, and
sal prunelle, but without saw-dust; the antimony communicating silver
brilliancy to the flame. It may also be formed, by employing, in
given proportions, saltpetre, sulphur, and charcoal, the particular
effect depending upon the proportions; or by using antimony in lieu
of the charcoal, or in the place of the antimony, steel-filings.
Whether antimony or steel-filings are used, the effect of their
combustion is the same, forming in the one instance, an oxide of
antimony, and in the other, an oxide of iron. Both gold and silver
rain is employed chiefly for sky-rockets. As to the colours required,
they may be formed of other substances.
The charges for _water-rockets_ are also various. In some of which,
besides the usual ingredients, (meal-powder, saltpetre, and
sulphur,) sea-coal, steel-filings, saw-dust, &c. enter into their
composition.
As to the different compositions, it will be sufficient to remark,
that for _wheels_, _fixed cases_, _sun cases_, _gerbes_, _Chinese
fire_, _tourbillons_, _water balloons_, _water squibs_, _serpents_,
_port-fires_, _cones_, _globes_, _air-balloon fuses_, _fire-pumps_,
and many others to be noticed hereafter, the basis of them is either
gunpowder or saltpetre, and sulphur and charcoal, with or without
additions. With respect to the composition of the stars of different
colours, it is to be observed, that the particular colour is given
by pulverized cast-iron, steel-filings, camphor, amber, antimony,
perchloride of mercury, (corrosive sublimate), ivory-dust, copper,
frankincense, &c. To produce _tails of sparks_, pitch or rosin is
added. Stars which produce _some_ sparks are usually made by using
gum water in mixing the composition. The gum appears to produce
a separation of the inflammable substances, and, as it is not
combustible, to check, as it were, the rapidity of the combustion. In
some preparations, also, isinglass or fish-glue is used in solution.
This, no doubt, acts in the same manner, as well as to give firmness
to the composition; but its solution is also used as a vehicle. On
the same principle also, we learn the use of caustic ley, quicklime,
&c. in preparing match-rope. After soaking the cord in a solution
of nitre, it is afterwards dipped into ley, which is nothing more
than a solution of potash rendered caustic by means of quicklime.
The potash evidently checks the combustion. The formulæ for slow
match, are, however, various. In the match-wood, also, prepared from
the wood or bark of the linden, the wood is usually first soaked in
a solution of saltpetre, and afterwards in a solution of acetate
or sugar of lead, &c. For the same purpose, nitrate of copper is
recommended. For stars of a yellow colour, besides gum arabic, or gum
tragacanth, saltpetre, and sulphur, the addition of powdered glass,
orpiment, (sulphuret of arsenic), and white amber, are occasionally
made. The colour is owing to the amber and the orpiment, which have
the property of communicating it to flame. We may observe, generally,
that the colours produced by different compositions, is a subject of
importance to the pyrotechnist. He should know the properties of each
substance, and the effect of each ingredient; and, with respect to
their action, be able to foretell the appearance of the flame, and
other circumstances connected with the art. As a general example,
we may state, that sulphur gives a blue; camphor, a white, or pale
colour; saltpetre, a clear white yellow; amber, a colour inclining
to yellow; muriate of ammonia, (sal ammoniac), a green; antimony,
a reddish; rosin, a copper colour, and Greek pitch, a bronze, or
a colour between red and yellow. In using these substances, the
following remarks may be useful;--that for producing a white flame,
the saltpetre should be the chief part; for blue, the sulphur;
for flame inclining to red, the saltpetre should be the principal
ingredient, using at the same time, antimony and pitch. (See _matches
of different colours_, in Part ii.)
Coloured flame may be produced by various other substances, many
of which are expensive, and therefore could not be employed
economically. Thus, in fire-works made with hydrogen gas, or
inflammable air, which have a pleasing effect, by forcing the gas,
either from a bladder, oiled-silk bag, or gas-holder, through a
variety of revolving jets, which are so arranged as to exhibit stars,
or through pipes furnished with small apertures, &c. to resemble
different standing figures,--the effect may be varied by previously
mixing the gas with the vapour of ether, and other substances, which
communicate to the flame, particular colours, which, in a darkened
room, are extremely brilliant. Cartwright's fire-works are formed in
this manner. (See _fire-works with inflammable air_.)
Muriate of strontian, mixed with alcohol, or spirit of wine, will
give a carmine-red flame. For this experiment, one part of the
muriate is added to three or four parts of alcohol. Muriate of lime
produces, with alcohol, an orange-coloured flame. Nitrate of copper
produces an emerald-green flame. Common salt and nitre, with alcohol,
give a yellow flame. (See _Illuminations and Transparencies_.)
In addition to the facts already stated, it may be proper to observe,
that the ingredients employed to _show in sparks_, which are rammed
in _choaked cases_, are various, according to the colours required;
as black, white, gray, and red. The black charges are composed
of meal-powder and charcoal; the white, of saltpetre, sulphur,
and charcoal; the gray, of meal powder, saltpetre, sulphur, and
charcoal; and the red, of meal-powder, charcoal, and saw-dust. These
are considered regular or set charges, to which we may add two
others, called compound and brilliant charges. The compound charges
contain a variety of substances which afford sparks; and hence,
besides the usual inflammable bodies, saw-dust, antimony, steel and
brass-filings, are used. The brilliant fires owe their particular
effect to the presence of steel-filings, or pulverized cast-iron.
Iron, in any of its states, when minutely divided, has the same
effect.
Quick match is usually formed of cotton, by soaking it in a solution
of nitre, and adding meal-powder. A solution of isinglass is
sometimes used. The etoupille of the French is of the same nature.
The manner, quick and slow match, &c. are prepared, with the various
formulæ, will be considered under their respective heads. Touch
paper, for capping serpents, crackers, &c. will also be noticed. The
pyrotechnical spunge owes its inflammability to nitre.
In the various composition of aquatic fire-works, although more
care and attention are required, it is to be observed, that, in
forming water-rockets, horizontal wheels, water-mines, fire-globes,
water-balloons, water-squibs, water-fire-fountains, and the like,
substances are generally used along with the usual ingredients,
which, under particular circumstances, may be said to _repel_, as
well as resist the action of the water; and in this particular
they resemble the celebrated Greek fire, of which we shall speak
hereafter. This remark, however, applies only to certain works. After
the rockets have been filled, their ends are dipped in melted rosin
or sealing-wax, or secured with grease.
Fire-works, usually exhibited in rooms, are made with odoriferous
gums and perfumes, and hence are called odoriferous fire-works.
We may remark, that the odour or perfume is given by a variety of
substances; for these, at a high temperature, are partly consumed,
and partly evaporated. Thus camphor, yellow amber, flowers of
benzoin, myrrh, frankincense, cedar-raspings, and the essential oils,
particularly of bergamot, are employed for this purpose. Scented
fire-works are of the same character. The Italians and the French,
who have made more experiments in Pyrotechny, than other nations,
have improved odoriferous fire-works. In these compositions, they
also employ storax, calamite, gum benzoin, and other substances.
_Scented fire_ was greatly in use in Egypt, Rome, and Athens, at
their fetes and public ceremonies. The unpleasant smell which
gunpowder, sulphur, &c. occasion in a confined apartment, has induced
the modern artificers to add sundry odoriferous substances to their
pyro-mixtures. On this subject, it will be sufficient to observe,
that the _scented vase_, which was in use at Athens, contained the
following substances: storax, benzoin, frankincense, camphor, gum
juniper in grains, and charcoal of the willow. It does not appear
that nitre was employed. The custom of burning frankincense before
the altar, is indeed very ancient; for, in the primitive temple at
Jerusalem, the custom was adopted by the priests in the Sanctum
Sanctorum, and is continued by the Greeks and Armenians, the Jews,
the Turks, the Persians, (especially the followers of Zoroaster),
preserve this custom. The _Holy Fire_ of the latter is nothing more
than the inflamed carburetted hydrogen gas, which comes from the
naphtha ground at Baku.
Besides the use of nitre in pyrotechnical compositions, as it forms
an essential part in all of them, there is another salt we had
occasion to notice, of which an account will be given hereafter,
that affords a variety of amusing experiments. This salt is the
hyperoxymuriate or chlorate of potassa. Although it has neither
been used for fire-works on an extensive scale, nor does it enter
into any of the compositions usually made for exhibition, yet its
effect is not the less amusing. Some general idea may be had of its
effect, by stating a few experiments. If a mixture of this salt and
white sugar be made in a mortar, and the mixture laid on a slab or
tile, and a string wetted with sulphuric acid, (oil of vitriol), be
brought in contact with it, or a drop or two of the acid be let fall
upon it, a vivid combustion will take place. In this experiment, the
acid decomposes the salt, and the oxygen unites with the carbon and
hydrogen of the sugar, and forms carbonic acid and water. The same
salt, rubbed in a mortar with sulphur, will produce a crackling noise
resembling that of a whip; and if a mixture of the two be struck with
a hammer, the percussion will cause a loud detonation. The same thing
happens when phosphorus is used, but the detonation is more violent.
Various other experiments may be made with it. It forms the principal
part of the match, called the _pocket lights_. These are made, in the
first place, by dipping the wood previously cut in splints in melted
sulphur, and afterwards in a mixture of this salt with sugar, which
is moistened with water. The match is then dried. When used, it is
dipped in sulphuric acid. The red colour, usually given to the match,
is formed by mixing with the composition some vermillion. Another
application of the same principle, is the firing of cannon. For this
purpose, after the tube is filled with powder, a covering of the same
mixture is applied when mixed with water. It is then dried. When the
tube is put in the vent, a drop of sulphuric acid will inflame it,
and consequently discharge the gun. This salt also, when mixed with
sulphur, may be used to fire fowling pieces, provided the lock be so
constructed, as in a late invention, that it acts by percussion. (See
Thenard's Priming powder.)
The Rev. Alexander Forsyth of Alexander Forsyth of Belhelvie,
in Aberdeenshire, Scotland, took out a patent for a new kind of
gun-lock, to be used without a flint, and has contrived to inflame
powder merely by percussion. The powder employed for priming,
consists of chlorate of potassa and sulphur. The gun-lock is
calculated for firing cannon as well as musquetry; it is contrived
to hold forty primings of such powder; and the act of raising the
cock primes the piece. Each charge of priming is supposed to contain
one-eighth of a grain of the salt. There are other substances which
also produce fire by percussion. The fulminating silver, mixed with
any substance, or used by itself, will detonate by percussion. It
should be used with great caution. A grain or two will explode with
great violence. (See _Detonating Works_, _Waterloo crackers_, _&c._)
There are several other metallic preparations which detonate
violently, such as the fulminating gold, fulminating mercury, &c.
all of which must be used with extreme caution. (See the respective
articles.)
_Sec. IV. Of Illuminations._
Although nothing of much importance can be said on the subject of
illumination, yet at the same time, as it is connected with some
remarks we will hereafter offer, it may be proper to observe, that
the practice of illuminating, as well as the exhibition of fire-works
in public rejoicings, has been in use for many years. The former
indeed has been customary for many centuries. We have, however,
appropriated an article to the manner of forming illuminations and
transparencies, and also on imitative fire-works.
Illuminations, whether with lamps, candles, flambeaux, &c. may be
rendered more impressive from the manner of their arrangement. In
some instances different coloured flames have been used; and the
effect in this case is more grand and beautiful.
The public lighting of cities on festivals, and particularly on
joyful occasions, called illuminations, is of great antiquity.
Indeed, illuminations are a general expression of the public feeling,
and should, on important occasions, be encouraged. Victories gained
over an enemy by the army or navy are subjects of rejoicing. While,
in such cases, illuminations may be viewed as an _expression_ of the
feelings of the people, they serve moreover to stimulate, in the
spirit of the _amor patriæ_, the future actions of the patriot and
the soldier; and while such rejoicings are demonstrative of victory,
they are equally expressive of that virtuous feeling, of which every
one must partake, on the return of an honourable peace.
What could have been more impressive than the brilliant
spectacle exhibited in Paris in 1739, on the return of peace?
Besides illuminations, the fire-works on that occasion were truly
magnificent. The same may be said of those at Pont Neuf, and those
at Versailles in the same year. We shall have occasion to speak of
them, when we come to the arrangement or the order of fire-works for
exhibition.
The Egyptians at an early period, made use of illuminations, and
particularly at a festival, which is mentioned by the Greek authors.
During the festival, as Herodotus says, lamps were placed before all
the houses throughout the country, and kept burning the whole night.
During the festival of the Jews, called _festum encæniorum_, the
feast of the Dedication of the Temple, the lamps were lighted
before each of the houses, and the festival continued eight days.
Illuminations were also used in Greece, according to a passage in
Æschylus. When games were exhibited in the night-time at Rome, the
forum was lighted. Caligula, on a similar occasion, caused the city
to be illuminated. In honour of the great orator Cicero, as he was
returning home at night, after the defeat of Cataline's conspiracy,
lamps and torches were lighted in all the streets. Byzantium,
afterwards Constantinople, was ordered to be illuminated with lamps
and wax candles on an Easter eve, in the time of Constantine.
That this custom was prevalent among the christians in the first
century, is evident from many authors. Professor Beckman, in his
_History of Inventions_, vol. iii, p. 383, says, that "the fathers of
the first century frequently inveigh against the christians, because,
to please the heathens, they often illuminated their houses, on
idolatrous festivals, in a more elegant manner than they. This they
considered as a species of idolatry. That the houses of the ancients
were illuminated on birth-days, by suspending lamps from chains, is
too well known to require any proof."
At Damascus, the Turks always keep a lamp burning over the tomb, as
it is called, of Ananias, which they much reverenced. It is said
to be in the same house in which St. Paul lodged with Judas. (See
_Maundrel's Travels from Aleppo to Jerusalem_.)
Lamps, according to Dr. Pococke, are kept continually burning in the
Jewish synagogue at Old Cairo, said to have been built about sixteen
hundred years ago. (See _Pococke's Travels through Egypt_.)
In Persia, lamps are kept burning in consequence of some religious
notion, and particularly at the sepulchre of Seid Ibraham. (See
_Travels through Muscovy into Persia_.)
A lighted lamp is frequently put up in Persia as a mark to shoot
at. To be a good shot, the marksman must extinguish it. At the
celebration of the feast called Ashur or Ten, from its lasting ten
days, which is kept in memory of Hossein, the youngest son of Hali,
the Persians make use of rags dipped in suet and naphtha, and burn
them in lamps; and their courts are lighted up with thousands of
lamps, the light from which is increased by as many more lanterns
made of paper, that are fastened to cords drawn across the court.
The Chinese, in celebrating their solemn feasts, especially on the
15th day of the first month, called the Feast of the lanterns, from
the multitude and grandeur of the lamps they exhibit in the evening,
are remarkable for the splendour of their exhibitions. We are
informed, (_A Description of China, &c._), that many of the grandees,
retrenching every year something from their tables, apparel, and
equipage, to show the greater magnificence in the lanterns, used on
this occasion, expend the sum of 2000 crowns. The largest are about
twenty feet in diameter, and are lighted by an immense number of wax
candles and lamps; but those that are most common, are of a middling
size. These are generally composed of six faces, or panes, each of
which has a frame of varnished wood, adorned with gildings four
feet high, a foot and a half broad, covered on the inside with fine
transparent silk, on which are painted flowers, trees, rocks, and
sometimes human figures. The painting is very curious, the colours
lively, and the wax candles give the painting a beautiful splendour.
These six pannels joined together, compose a hexagon, surmounted at
the extremities by six carved figures, that form its crown. Around it
are hung broad strings of satin, of all colours, with other silken
ornaments, that fall upon the angles without hiding the light of the
pictures. The feast of the lanterns is also celebrated by bonfires
and fire-works.
Candles are also used for the same purpose. Chandeliers, differently
made, and holding a greater or smaller number of candles, add greatly
to the effect.
The candles used by the natives of Otaheite are curiously made.
According to Cooke, (_First Voyage, &c._), they have candles made of
a kind of oily nut, which they stick one over another upon a skewer
thrust through the middle of them. The upper one being lighted, burns
down to the second, at the same time consuming that part of the
skewer which goes through it; the second, taking fire, burns in the
same manner down to the third, and so of the rest. These candles give
a tolerable light, and some of them will burn a considerable time.
The lighting of streets, Beckman considers in some respects to be a
modern invention, and after quoting various authorities concludes,
that, of modern cities, Paris was the first that followed the example
of the ancients by lighting its streets. It appears, therefore,
that the practice of illuminating was reserved by the ancients
for some great occasion, that lighting of the streets was more or
less partial, and confined to particular places, and that it was
not general without some particular occasion called for it. (See
_Illuminations_.)
Kircher, the German philosopher, had a wick made of amianthus,
which burnt for two years without injury, and was at last destroyed
by accident.[8] The Greenland stone flax, which is the same as
amianthus, the Rev. Mr. Edge says is used in Greenland for lamp
wicks, and burn without being in the least wasted, whilst supplied
with oil or fat. Ellis (_Voyage for the Discovery of a North-West
Passage_), found the mountain flax, (asbestus), among other minerals,
on the Resolution Islands, inhabited by the Esquimaux, which is
used for similar purposes. We may remark here, that the Esquimaux
use stone for lamps, which they hollow out, and, according to
circumstances, use also dried _goose dung_ for wick.
_Sec. V. Of some of the Feats or Performances by Fire._
We introduce this subject to show, that certain kinds of fire-works
have been employed for the purpose of deceiving the ignorant, and
amusing the better informed part of mankind. Many of the tricks of
jugglers and slight-of-hand men, and the performances of certain
rites, particularly by the ancient magi, and pagan priests, come
under this head. Sundry substances, in connection with artificial
fire, have been employed by persons of this description. It is true,
our account of them is rather imperfect. Had the works of Celsius,
which he wrote against the ancient magi, been preserved, we would,
no doubt, have been better acquainted with the art of the ancient
conjurors and jugglers.
Professor Beckman has endeavoured to trace the origin of the
necromantic art; but although of opinion that it is very ancient, and
founded in superstition and unnatural causes, he is of opinion, that
the works of Celsius, which are lost, were full on the subject, and
for that reason our account must be imperfect.
Plain common sense, but with enlightened reason, has alone convinced
mankind of the follies of older generations, and of relying on
superstitious ceremonies, or believing in miracles, exorcism,
conjuration, necromancy, sorcery, or witchcraft.
The torch of reason, and experimental philosophy have dispelled
the clouds of ignorance and superstition; and men, becoming more
enlightened as they progress in the investigation of truth, are no
longer under the influence of false doctrines, or led away by a
bigoted priesthood. Philosophical experiments, the various optical
illusions, the effects of electricity, magnetism, &c. are founded on
immutable truths, which become the more familiar as we progress in
science.
Truth, however, although elicited by the genius of great men, who
have lived in every age, was suffered to be brought to the rack;
because it either militated against the views of the priesthood, and
enlightened the people, or curtailed the ecclesiastical power and
authority of the church.
Because Anaxagoras taught that the sun and stars were not deities,
but masses of corruptible matter, he was tried and condemned in
Greece. Accusations of a similar nature contributed to the death of
Socrates. Copernicus, in consequence of the threats of bigots and the
fear of persecution, was prevented from publishing, during his life
time, his discovery of the true system of the world; and it is well
known, that the great Galileo was imprisoned a year, and then obliged
to renounce the motion of the earth, because he asserted it. In 1742,
a commentary on Newton's _Principia_, one of the first productions of
human genius, was not allowed to be printed at Rome, in consequence
of its promulgation of this doctrine; and, in the true spirit of
_priest-craft_, the commentators were obliged to prefix to their work
a declaration, _that on this point, they submitted to the decisions
of the supreme pontiffs_! Such are the results of bigotry, ignorance,
superstition, and especially of civil and ecclesiastical governments,
that consider learning a curse, and ignorance a blessing! Happily
for the people of the United States, their co-equal rights and
enlightened reason, will ever guarantee them against tyranny on the
one hand, and fanaticism on the other. Superstition has always been
an engine of oppression, and wherever it prevails, the powerful are
sure to make use of it to oppress and destroy the weak.
Another instance of the assumed prerogative of the holy fathers
may be found in their conduct towards the house of Medici; for the
pontiffs, it is known, induced the house of Medici, by granting it
the cardinalship, to suppress the academy del Cimento. The reason
of this step is obvious to all; for they were sensible, that, if
the people became once enlightened, they would lose their weight,
their influence, and authority. But as jugglers are conscious of
their gross deceptions, working on the imagination and credulity
of the multitude, they in this respect appear at least to know
themselves. Like the juggler mentioned in Xenophon, who requested the
gods to allow him to remain in places, where there was much money
and abundance of simpletons, they acted as the prototype. We might
enumerate, if it were not irrelevant to our subject, a number of
facts concerning these impostors.[9]
The miracles wrought by Moses, as recorded in the books of Exodus,
were, we have reason to believe, by the immediate command of a
supreme power. When Moses had commissioned Aaron (_Exodus_, chap.
vii, verse 9, 10, &c.) to be a prophet, Aaron took a rod and cast
it before Pharaoh and his servants, and it became a serpent; but it
seems, however, that Pharaoh called the wise men and the sorcerers,
called the magicians of Egypt, who performed the same thing with
their enchantments; "for they cast down every man his rod, and they
became serpents: _but Aaron's rod swallowed up their rods_." It
appears that on another occasion, the waters were turned into blood
by smiting them with the rod; "and the magicians of Egypt did so
with their enchantments." When Aaron was commanded to stretch forth
his hand with his rod over the streams, &c. frogs appeared upon the
land, and the magicians did so likewise; but when vermin were brought
forth, by smiting the land, the magicians were unsuccessful, and said
unto Pharaoh, "_This is the finger of God_." In the continuation of
the plague, Moses and Aaron were commanded to take the ashes of the
furnace, before Pharaoh, and sprinkle them up towards Heaven; and
it became a hail on man and beast, but the magicians were affected,
and could not stand before Moses. When Moses stretched forth his rod
towards heaven "hail, and fire mingled with hail," came down; and
on another occasion, they brought forth locusts. When this plague
ceased, Moses caused darkness to prevail.
We will merely observe, that, with regard to the magi of Egypt,
who it is known possessed all the learning of the day, and were
celebrated in after ages for superior wisdom, so much so that
many of the Grecians resorted there to be initiated into their
mysteries,--they were of a different description from those who
really worked miracles, according to divine inspiration. Hence we
find, that, although distinct in their character, the magicians
of Egypt pretended to perform certain rites, and to work upon
the feelings of the people. Their initiary process, which the
Pythagoreans in many respects pursued, and traces of which are extant
in the order of free-masonry, was merely intended to preserve their
knowledge within the pale of, and veiled in, hieroglyphic mystery,
which none but the initiated could understand. Priestley, in his
_Institutes of Moses_, points out the difference between the magi,
so called, and the rites and ceremonies of the ancient Hebrews. But
the imposition practised on mankind, even in modern times, aided by
engines of the most abominable kind, as instruments of torture, in
the inquisitorial tribunals of Portugal and Spain, are sufficient of
themselves to call down the vengeance of impartial justice.
That the magicians were conscious of their inability to work
miracles, is evident from their own declaration; for, after vermin
had been brought forth by Moses and Aaron, they endeavoured to do the
same, and being unsuccessful declared, that _this was the finger of
God_; and many other instances are recorded of their attempts being
altogether abortive. It appears also, that at first they believed
they were able to perform all that Moses had done; and Pharaoh
himself, by calling them together for that purpose, seemed to be of
the same opinion, until he and his servants were finally convinced
that Moses and Aaron wrought such miracles by inspiration. There can
be no relation whatever between Moses and the magicians; for although
he was, if we may judge from biblical history, acquainted with all
the knowledge of the magicians, his mission was altogether of a
different character. Many of the modern Greek and Armenian priests,
in their celebration of the holy fire, palm upon their credulous
followers, a belief, that they possess the power of working miracles,
as will appear from the account we shall give of them. We will not
enlarge on this subject at present, but pass on to consider the more
common performances, which have excited the wonder and admiration of
mankind.
The deception of breathing out flames, which excites the astonishment
of the ignorant, is very ancient. When the slaves of Sicily, about
two centuries ago, made a formidable insurrection, and avenged
themselves in a cruel manner for the severities which they had
suffered, there was among them a Syrian named Eunus, a man of great
craft and courage, who, having passed through many scenes of life,
had become acquainted with a variety of arts. He pretended to have
immediate communication with the gods; was the oracle and leader of
his fellow slaves; and, as is usual on such occasions, confirmed
his divine mission by miracles. When, heated by enthusiasm, he was
desirous of inspiring his followers with courage, he breathed
flames or sparks among them from his mouth while he was addressing
them. We are told by historians, that, for this purpose, he
pierced a nut shell at both ends, and, having filled it with some
burning substance, put it into his mouth and breathed through it.
Some affirm, that he used tow previously soaked in a solution of
saltpetre. The deception at present is much better performed. The
juggler rolls together some flax or hemp; sets it on fire; and
suffers it to burn till it is nearly consumed; he then rolls round
it, while burning, some more flax, and by these means the fire may
be retained in it a long time. When he wishes to exhibit, he slips
the ball into his mouth and breathes through it; which again revives
the fire, so that a number of weak sparks proceed from it; and the
performer sustains no hurt, provided he inspire the air not through
the mouth but the nostrils.
By this art, the rabbi Bar-Cacheba, in the reign of the emperor
Hadrian, made the credulous Jews believe, that he was the hoped for
Messias, and two centuries after, the emperor Constantius was thrown
into great terror, when Valentian informed him, that he had seen one
of the body guards breathing out fire and flames in the evening.
It appears evident from the writings of Herodotus, that the ancients
possessed a knowledge of attracting lightning, or the electric fluids
with pointed instruments made of iron. He informs us, that the
Thracians disarmed heaven of its thunder-bolts, by discharging arrows
into the air; and the Hyperboreans by darting into the clouds, pikes
headed with pieces of sharp pointed iron.
Pliny speaks of a process, by which Porsena caused fire from the
heavens to fall upon a monster which ravaged his country. He mentions
also, that Numa Pompilius, and Tullius Hostilius practised certain
mysterious rites to call down the fire from heaven. What these
mysterious rites were is of no moment; the fact is sufficient.
Tullius, because he omitted some prescribed ceremony, is said to have
been killed by the fire. A similar accident happened in France with
the electrical kite.[10]
For deceptions with fire, the ancients employed a number of
inflammable substances, which they dexterously used; among them,
naphtha, a fine bituminous oil, which readily inflames, was
principally used. (For the effect of _naphtha_, _see_ _Greek
fire_.) Galen informs us, that a person excited great surprise
by extinguishing a candle, and again lighting it without any
other process than holding it against a wall or a stone. This,
Galen observes, (_De Temperamentis_, iii. 2, p. 44.) was effected
in consequence of the wall or stone being previously rubbed
with sulphur, which, however, must have been something more. He
also speaks of a mixture of sulphur and naphtha. If it had been
phosphorus, or some of its preparations, it would appear more
probable.
Plutarch relates the secret effects of naphtha, and observes, that
Alexander was astonished and delighted, when it was exhibited to him
in Ecbatana. Medea destroyed Creusa, the daughter of Creon, with
this oil. This fact is stated by Plutarch, Pliny, Galen, and others,
and believed by Beckman. She sent, it appears, to the unfortunate
princess, a dress covered with it, which burst into flames as soon
as she approached the fire of the altar. The dress of Hercules,
which also took fire, was dipped in naphtha, though said to be in
the blood of Nessus. On the subject of naphtha, Beckman remarks,
"that this oil must have been employed when offerings caught fire in
an imperceptible manner. _In all periods of the world, priests have
acted as jugglers to simple and ignorant people._"
The most ludicrous account of the necromantic art, by which similar
tricks were performed, is that given by Celini, (_Life of Benvenuto
Celini_, a Florentine Artist, by T. Nugent, LL. D. &c.) of a Sicilian
priest, who drew circles on the floor with various ceremonies, using
fire and different perfumes. Having made an opening to the circle,
and thrown perfumes into the fire at a proper time, he observes, that
in the space of an hour and half, "there appeared several legions
of devils, insomuch that the amphitheatre was quite filled with
them." Benvenuto, it seems, at the instance of the priest, asked
some favours of them, which, however, he never realized. At a second
exhibition he held a _pentagorun_, while the priests questioned
the leaders of the demons "by the virtue and power of the eternal
uncreated God," using the Hebrew, Greek, and Latin languages. The
Demons appeared more numerous than at first, and more formidable.
He states that "quivering like an aspen leaf, he took good care of
the _perfumes_," and was directed by the priest "to burn proper
perfumes." This ceremony was continued until the "bell rang for
morning prayers," and the priest "stripped off his gown and took up
a wallet-full of books," declaring, "that as often as he had entered
magic circles, nothing so extraordinary had ever happened to him!"
How is it, in the language of professor Beckman, that "in all periods
of the world, priests have acted as jugglers to simple and ignorant
people?" * * * * *
This same Benvenuto Celini, however, was a man of intelligence.
He wrote a work called the _History of Jewelry_; in which the
first idea of phosphorescent mineral bodies is to be found. This
work was written in the beginning of the 16th century. His life,
although singularly marked, what with popes, priests, artists, and
necromancers, presents a singular retrospect.
What was more absurd, and even profane, than the tricks of Joseph
Balsamo, called Il Conte Cagliostro, who with Schœpfer, revived
the study of the magical arts; and who with invocations, friction,
fumigations, and optical deceptions astonished the ignorant of their
day. Whether like Æneas, in his descent to hell, they made their way
with their falchions through crowds of ghosts, or like Dioscorides,
relied on the efficacy of herbs, or like Paracelsus, carried an evil
spirit in their canes, or wore a _jewel_ like Shakspeare's toad,
which possessed marvellous virtues, or employed the magic stone
(_agate_) of the east, and invoked their _urim and thummim_,--it
is certain they worked upon the imagination of the people. By the
application of _conium maculatum_, (hemlock) consisted the ceremony
of ordaining a Hierophant; by the hartshorn of Orpheus, they had a
divine remedy for the passions of the body; and by a mixture of _new
mustard and olive oil_, they could produce a symphony, which invoked
the spirits, and, Pythonesis like, declare to the people, that they
"_had devils in their bellies_!!"
Of the phial of Cagliostro, Cardan relates that he had this phial
twice exhibited to him, and complains bitterly of having seen
nothing, after the anthem _Sancte Michael_, but some bubbles
that issued from the bottom, though it was believed that these
bubbles were angels! He says, "_Nihil tamen omnino vidi poste
hanc invocationem nisi bulas pauculas quasdam ex imo gutti fundo
exæstuantes_." Aulus Gellius and Hero mention tricks of this
kind practised by the Egyptians. Roger Bacon, the alchymist, was
excommunicated by the pope, and imprisoned ten years, for supposed
dealings with the devil.
Equally absurd to a man of reflection, are the observations of
antiquated writers on spontaneous generation, by heat. Borello
(_Physical History_) tells us, "that fresh water craw fish may be
regenerated, by their own powder, calcined in a crucible, then boiled
in water with a little sand, and left to cool, for a few days; when
the animalcula will appear swimming merrily in the liquor, and must
be then nourished with beef blood, till they attain the proper
size to stock your ponds with."[11] The Sieur Pogeris and M. de
Chamberlan, both agree with Signior Borello, but, in the chemistry of
the matter, they add that the operation must be performed, _during
the full of the moon!_ If this _lunar system_ be adopted, would not
the _crab_ also, have been a more favourable _sign_ to have ruled the
nativity of _craw fish_?
Swift, however, alludes to these agencies, fallacious as they are, in
the following lines:
"So _chymists_ boast they have a power,
"From the dead ashes of a flower,
"Some faint resemblance to produce,
"But not the virtue, taste, or juice."
Rochos, equally absurd with Borello, says, in _The Art of Nature_,
that the ashes of _toads_ will produce the very same effect, as the
powder of _crabs' eyes_! Reasoning upon that ridiculous and unnatural
principle of Cæsalpinus, in his comment on Aristotle, _Quæcumque ex
semine fiunt, eadem fieri posse sine semine_, the procreation of eels
from rye-meal, or mutton broth was predicated.
_Julius Camillus_, however, would out-do nature herself; for _Amatus
Lusitanus_ affirms, that he has seen his phials full of _homunculi_
complete in all their parts! Paracelsus (_De Rerum Natura_,) had the
same and many other absurd notions. What, we may truly say, has not
been palmed upon the world, when we are told, that the following
translation from a Hague Gazette, which appeared in the _British
Evening Post_, No. 1645, contained facts, which were confidently
believed by the ignorant:
"Mr. Tunestrick, by origin an Englishman, has just exhibited at
Versailles, a very singular experiment. He opened the head of a
sheep, and a horse from side to side, by driving a large iron wedge
into the skull, by means of a mallet; drew the wedge out afterwards,
with pincers, and recalled the animals to life, by injecting through
their exterior aperture with a tin syringe, a spirituous liquor of
his own composition, to which he attributes surprising effects!
The taste of this liquor resembles that of _Commandus Balm_!!" The
remarkable effects of galvanism, however, are well authenticated;
but _resuscitation_, notwithstanding all apparent life, has in no
instance, to our knowledge, been effected. (See Ure's _Chemical
Dictionary_, article Galvanism.)
Among other tricks, we may mention those with serpents, especially in
the East Indies, and neighbouring islands, where a certain class of
people exhibit them for money.[12]
Persons who could walk over red-hot coals, or red-hot iron, or who
could hold them in their hands and their teeth, are frequently
mentioned. In the end of the 17th century, Richardson, an Englishman,
was a great adept in this performance. We are assured he could chew
burning coals, pour melted lead upon his tongue, swallow melted
glass, &c; but the fact is incredible.
It is true, that the skin may be prepared in such a way as to become
callous and insensible against the impression made on the feet
and hands. It may be rendered as firm as shoes and gloves. Such
callosity may be produced, if the skin is continually compressed,
singed, pricked, or injured in any other manner. Beckman relates,
that in 1765, he visited the copper-works at Awestad, when one of the
workmen, for some money, took some of the melted copper in his hand,
and after showing it, threw it against a wall. He performed a variety
of other experiments with the melted metal.
The workmen at the Swedish melting-house have exhibited the same
thing to some travellers in the 17th century. The skin is first
rendered callous by frequently moistening it, as Beckman says, with
sulphuric acid; and also, he remarks, by using the juice of certain
plants. The skin must also be rubbed frequently, and for a long time,
with oil. Haller, in his _Elementa Physiologica_, V. p. 16, speaks of
this fact.
The manner of rendering the hands callous, or insensible, so that
they may take up, and hold, ignited iron, charcoal, or other
substances, may be seen in an English publication of 1667. The
_Journal des Savants_, of 1677, contains the secret. "It consists
in applying to the hands, various pastes, with spirits of sulphur,
(sulphuric acid,) which destroys the epidermis, &c. and the nervous
energy." This corroborates the account by Beckman. We read that
Richardson had prepared his tongue in such a manner, that he could
hold on the point of it a live coal, covering it first with pitch,
rosin, and sulphur, and could hold a piece of ignited iron between
his teeth. After showing the coal on his tongue, he would then
extinguish it in his mouth. The _Mémoires de l'Académie_ state, that
a person who is salivated can put a live coal in his mouth. The
_Dictionnaire de l'Industrie_ observes, that the sulphur diminishes
the heat of the coal, for the flame is less hot than a candle; and
that the flame of a combination of pitch, rosin, and sulphur, is
still less hot, and by no means so considerable as we would imagine.
In the experiment, the rosin is not melted, and the flame of the
sulphur is inconsiderable. M. Gallois observes, that he witnessed in
the Swedish iron founderies, the men hold melted cast iron in their
hands, doubtless having them previously prepared.
The traces of this art may be found in the works of the ancients. A
festival was held annually, on Mount Soracta, in Etruria, at which
the Hirpi, who lived not far from Rome, jumped through burning coals,
and on this account had certain privileges granted them by the Roman
Senate.
Women also, we are informed, were accustomed to walk over burning
coals, at Cartabola, in Cappadocia, near the temple dedicated to
Diana. Servius remarks, that the Hirpi did not trust to their
sanctity so much as they did to the preparation of their feet for the
operation!
With respect to the ordeal by fire, which it seems was performed in
several ways, one was, that when persons were accused, they were
obliged to prove their innocence by holding in their hands red-hot
iron. This mode of exculpation, as it is called, was allowed only to
weak persons, who were unfit to wield arms, and particularly to monks
and ecclesiastics, to whom, for the sake of their security, the trial
by single combat was forbidden. In Grupius' learned dissertation, in
the German, p. 679, as quoted by Beckman, we read, that the trial
itself took place in the church, under the inspection of the clergy;
mass was celebrated at the same time; the defendant and the iron,
were consecrated, by being sprinkled with holy water; the clergy
made the iron hot themselves; and they used all these preparations,
as jugglers do many motions, only to divert the attention of the
spectators. It was necessary that the accused person should remain
at least three days and three nights, under their immediate care,
and continue as long after. They covered their hands both before and
after the proof; sealed and unsealed the covering: the former, as
they pretended, to prevent the hands from being prepared by art; and
the latter to see if they were burnt.
Some artificial preparation was undoubtedly necessary, or why
prescribe three days for the defendant, who, if they wished to make
him appear innocent, had a certain preventive against the actual
cautery? The three days allotted, after the trial, were requisite, in
order to restore the hands to their natural state. The sacred sealing
secured them from the examination of presumptuous unbelievers.
When the ordeal was abolished, it no longer was kept secret. In
the 13th century, an account of it was published by a Dominican
Monk, Albertus Magnus. In the work of this author, entitled, _De
Mirabilibus Mundi_, he has given the receipt for the composition. It
seems that it consisted in covering the hands with a kind of paste,
and not by searing them. The sap of the althæa, or marsh mallow, the
mucilaginous seeds of the fleabane, together with the white of an
egg, were mixed, and by applying this mixture, the hands were as safe
as if they had been secured by gloves. The use of this mixture, for
the same purpose, may be traced back, it is said, to a pagan origin.
In the Antigone of Sophocles, the guards, placed over the body of
Polynicus, which had been carried away and buried, contrary to the
orders of Creon, offered, in order to prove their innocence, to
submit to any trial: "We will," said they, "take up red-hot iron in
our hands, or walk through fire."
The ordeal, by heated ploughshares, was common in England. It seems,
according to English History, that queen Emma had charges preferred
against her, by Robert, archbishop of Canterbury, for consenting to
the death of her son Alfred, and preparing poison for her son Edward,
the Confessor. She claimed, by the law of the land, the ordeal, or
trial, by burning ploughshares. She passed the nine ploughshares
unhurt, which established her innocence, and caused the archbishop
to fly the kingdom. The chief trials, by ordeal, appear to have been
by fire, water, walking blindfold among heated ploughshares, and
swallowing consecrated bread, which last was introduced about the
time of pope Eugene. The custom was borrowed from the Mosaic law. An
example of its practice occurs in the New Testament, in the story
of Ananias and Sapphira; and the remembrance of it, as Blackstone
remarks, still subsists among common people, as "_May this morsel
be my last_;" "_May I be choked if it is so_," _and the like_; for
it appears, that this ordeal was a piece of bread of about an ounce
in weight, blessed by the priest, and given to the accused person,
who was to try and swallow it, praying that it might choke him if he
were guilty. The bible-ordeal, and the drowning-ordeal, are familiar
to every one, degrading as they all must have been to human reason,
and enlightened principles. Fox, in his _Book of Martyrs_, speaks of
various ordeals, as well as the cruel deaths, and inhuman punishments
inflicted, by the hand of bigotry, and fanaticism, under the cloak
of religion, which were nothing more than a base and impious
prostitution of its genuine principles.
Even among the modern Greeks, the same superstitious notions prevail.
Almost every cavern about Athens has its particular virtues, and is
celebrated for various things; and the offerings, made by Grecian
women, to the _destinies_, in order to make them propitious to their
conjugal speculations, are equally absurd. These offerings, by which
they are to work a miracle, consist of a cup of honey and white
almonds, a cake on a little napkin, and a _vase of aromatic herbs,
burning and exhaling an agreeable perfume_. We are told, however,
that those evil spirits, whose assistance is invoked, for vengeance
and blood, are not regaled upon cakes and honey, but on a piece of
a priest's cap, or a rag from his garment, which are considered as
the most favourable ingredients for the perpetration of malice and
revenge. When a person is _hated_, another absurd custom is used,
which is supposed to be followed by dreadful results. It consists
in placing before his door, a log of wood, burnt at one end, with
some hairs twisted round it. "This curse," says Mr. Dodwell, in his
_Classical Tour_, "was placed with due solemnity, at the door of the
English agent, Speridion Logotheti, while I was at Athens; but he
rendered it of no avail, by summoning a great number of priests, who
easily destroyed the spell, by benediction, frankincense, and holy
water!" This story is much in character with that of the exorcism
of rats, caterpillars, flies, and other insects, an old ritual of
the papal church, performed between the feasts of Easter and the
Ascension. A priest who resided at Bononia, performed the ceremony.
"I went," he says, "to exorcise the insects in that country,
accompanied by a curate, who was a droll fellow, and laughed at the
credulity of the people, while he pocketed their money." It appears,
however, that in all superstitious ceremonies, _fire_, under some
form, was a pre-requisite; but _ecclesiastical fire-works_ we leave
within the pales of the priesthood.
The author of the _Dictionnaire de l'Industrie_, vol. iii, speaks of
a trick, performed with a loaded musket and ball, which, although
apparently inconsistent, is nevertheless true, if we consider the
action of gunpowder equal. This _trick_ is stated to be the firing of
a musket, loaded with ball, at a person, without wounding, or in any
way injuring him.
By taking a ball of solid lead of a smaller size than the calibre of
the musket, and placing it on the charge in a gun, and as much or
nearly so of powder, _over the ball_, the effect we are assured is,
that when the gun is fired, the ball will pass out without any very
sensible force, and even drop a few yards from the gun, although the
report will be as great as if the charge and ball had been used in
the usual manner. This trick is often performed by jugglers, to the
great astonishment of the spectators. The mode of _catching a cannon
ball_ is also of the same character.
The proper charge of powder for the cannon, is divided into two
unequal portions, the lesser of which is placed in the gun as a
charge; the ball is placed on it in the usual way, and the rest of
the powder (by much the greater portion,) placed over the ball, the
lesser quantity being not more than a twelfth part of the whole. A
cannon, so charged, will not project the ball more than 20 yards,
where it might be caught with safety.
Any person who has been in the custom of shooting, must have
frequently observed, that when the shot happens to be mixed with the
powder, its range is impeded; and, under similar circumstances, they
have even been found only a few yards from the muzzle of the piece.
This fact I have witnessed, although I confess I never once reflected
on it.
As to the explanation of this phenomenon, it appears, that it can
only be accounted for by referring to the action of two opposite
forces, mutually repelling each other, added to that of the charge
under the ball; hence, the _reaction_ would be equal, if, under the
same circumstances, both charges were alike situated: but the effect
of the first charge is so much weakened by the counter effect of the
second, that the projectile force of the ball becomes comparatively
nothing.
There is another trick very often performed, which, however chemical,
is not looked upon in that light, neither do performers attempt to
explain it; we mean the exhibition of the _Glace Inflammable_ of the
French.
The preparation is made in the following manner: melt some spermaceti
over a fire, and add a sufficient quantity of spirit of turpentine,
and blend them together. The mixture when cold, will become solid,
having somewhat the appearance of ice. If made in hot weather, the
vessel containing the melted substances must be immersed in cold
water. It does not, we are told, remain in a solid state any length
of time.
It floats more or less in the fluid, which of course is the spirit of
turpentine. The trick, with this preparation, after having put some
of the solid and fluid substance together on a plate, is to pour upon
it concentrated nitric acid, or a mixture of eight or ten parts of
nitric acid, and two of sulphuric acid; inflammation ensues. It is no
other in fact than accension of the oil of turpentine; the addition
of the spermaceti is altogether secondary, and its effect, if any,
must retard instead of promoting the combustion of the turpentine.
The art of making this preparation is in rendering the essential oil
solid and transparent, without altering its inflammable properties.
There is another trick performed, by burning a thread, to which an
ear-ring is tied, and which, notwithstanding the thread is reduced
to a cinder, still holds the ring. This is what the French call the
_Bague suspendue aux cendres d'un fil_. The string is first prepared
by soaking it for 24 hours, in a solution of common salt, and drying
it; then tying it to a ring, and setting it on fire, avoiding any
vibration or oscillation of the string. It is obvious that the salt
serves to render the cinder cohesive.
We have an account in Maundrel's _Travels from Aleppo to Jerusalem_,
of the office of the _Holy Fire_. The ceremony is kept up by the
Greeks and Armenians, from a persuasion that every Easter eve, a
miraculous flame descends from heaven into the holy sepulchre, and
lights all the lamps and candles, as the sacrifice was consumed at
the prayers of Elijah.
"On our approaching the holy sepulchre," says Maundrel, "we found
it crowded with a numerous and distracted mob, who made a hideous
clamour; but with some difficulty pressing through the crowd, we got
up in the gallery next to the Latin convent, where we could have a
view of all that passed. The people began, by running with all their
might, round the holy sepulchre, crying out 'huia,' which signifies,
'_This is he_,' or, '_This is it_.' After this, they began to perform
many antic tricks: sometimes they dragged one another along the floor
round the sepulchre; sometimes marched round with a man upright
upon another's shoulders; at others, took men with their heels
upwards, and hurried them about with such indecency, as to expose
their nudities; and sometimes they tumbled round the sepulchre like
tumblers on a stage. In a word, nothing can be imagined more rude and
extravagant than what was acted upon this occasion.
"This frantic humour continued from twelve till four, and then the
Greeks first set out in a procession round the sepulchre, followed by
the Armenians, and marched three times round it with their standards,
streamers, crucifixes, and embroidered habits; and towards the end of
the procession, a pidgeon came fluttering into the cupola over the
sepulchre, at which the people redoubled their shouts and clamours,
when the Latins told the English gentlemen, that this bird was let
fly by the Greeks, to deceive the people with a belief that it was
a visible descent of the Holy Ghost. The procession being over,
the suffragan of the Greek patriarch, and the principal Armenian
bishop, approached the door of the sepulchre, cut the string with
which it was fastened, and breaking the seal, entered, shutting the
door after them, all the candles and lamps within having been before
extinguished in the presence of the Turks. As the accomplishment
of the miracle drew near, the exclamations were redoubled, and the
people pressed with such violence towards the door, that the Turks
could not keep them off with the severest blows. This pressing
forward was occasioned by the desire to light their candles at the
holy flame as soon as it was brought out of the sepulchre. The two
miracle-mongers had not been above a minute in the sepulchre, when
the glimmering of the holy fire was seen through some chinks in the
door, which made the mob as mad as any in bedlam; then presently came
out the priests, with blazing torches in their hands, which they
held up at the door of the sepulchre, while the people thronged with
extraordinary zeal to obtain a part of the first and purest flame,
though the Turks laid on with their clubs without mercy. Those who
got the fire immediately applied it to their beards, faces, and
bosoms, pretending that it would not burn like an earthly flame; but
none of them would endure the experiment long enough to make good
that pretension. However, so many tapers were presently lighted, that
the whole church seemed in a blaze, and this illumination concluded
the ceremony."
Maundrel afterwards observes, that the Latins take great pains to
expose this ceremony as a shameful imposition, and a scandal to the
Christian Religion: but the Greeks and Armenians, lay such stress
upon it, that they make the pilgrimages chiefly on this account; and
their priests have acted the cheat so long, that they are forced
now to stand to it, for fear of endangering the apostacy of the
people. They entertain many absurd ideas respecting the miraculous
power of the holy fire. Even the melted wax of the candle, which had
been lighted by it, is covered over with linen, and designed for
winding-sheets; "for they imagine," says Maundrel, "that if they are
buried in a shroud, smutted with this celestial fire, it will secure
them from the flames of hell!"
Before concluding this article, we shall mention a subject highly
interesting in optics, which, in some of its forms, was employed
by the old magicians; we mean the phantasmagoria. The exhibitions
of this kind, when first got up, drew the attention of Europeans,
and particularly the French, who greatly improved the apparatus and
machinery, and varied the forms and appearances. The principles of
the phantasmagoria are described in every work on Natural Philosophy,
which treats of optics. The _Dictionnaire de l'Industrie_,
_Encyclopedie Méthodique_, Biot's _Traité de Physique_, in French
and in English, the different treatises on philosophy and optics,
particularly Dr. Smith's, the Cyclopedias, &c. contain either a
description, or the principles of it. The third volume of Biot,
especially, is full on the subject of optics. With regard, however,
to the narrative and explanation of the appearance of the phantoms,
and other figures, a subject which immediately concerns us, the
account given by Mr. Nicholson, (_Journal of Natural Philosophy,
Chymistry, and the Arts_, vol. i, p. 147.) is the most interesting.
Connected with this optical illusion, is the imitation of lightning
and thunder, which, from the account, appears also to have been
performed.
The phantasmagoria may be considered nothing more than an application
of the magic lantern, the invention of which is attributed to Roger
Bacon, who was a contemporary with Vitellio, a native of Poland, who
published a treatise on optics, in 1270. John Babtista Porta, of
Naples, who discovered the camera obscura, having formed a society
of ingenious persons at Naples, which he called the Academy of
Secrets, wrote the _Magia Naturalis_, containing his account of this
instrument, and, it is said, the first hint of the magic lantern.
Kircher, it is known, received his first information of the magic
lantern from this book, and afterwards improved it.
Adams (_Lectures on Natural and Experimental Philosophy_, vol. ii,
p. 232. Appendix by the English editor) very justly observes, that
persons, unacquainted with the principles of optics, have been
surprised at the great illusion of their sight, by an artificial
construction of many optical instruments, exhibited by showmen and
others: such, for instance, as the optical and dioptrical paradox;
the endless gallery; the animated balls by simple reflection;
phantoms; causing the appearance of a flower from its ashes; the
optical perspective box, and the cylindrical mirror: to which we may
add, the enchanted bottle; the enchanted palace; the magic lantern;
the magician's mirror; the perspective mirror; the camera obscura;
distorting and oracular mirror; the diagonal opera glass, &c. &c.;
all which may be seen in Smith's _School of Arts_.
We may also remark, that optical exhibitions sometimes accompany
those of fire, when performed on a small scale. In the
phantasmagoria, for instance, whether before, or at the time the
exhibition commences, as well as after, thunder and lightning, if
well imitated, produces a good effect.
The mechanism of the phantasmagoria is concealed from the spectators,
who have only before their eyes a screen of gauze or gummed muslin
posited vertically, which serves as the ground of a picture,
where the images are depicted by reason of the transparency. The
apartment is deprived of all light, except that which proceeds
from an apparatus hid behind the screen. At the moment when the
operation commences, a spectre appears (as a skeleton, the head
of a celebrated person, &c.), at first extremely small, but which
afterwards increases rapidly, and thus seems to advance at a great
rate towards the spectators. And when the scene passes before them in
a room representing a cave hung with black, a solemn silence being
occasionally interrupted by mournful sounds from an appropriate
musical instrument, it is not easy for an observer to defend himself
from the impression of terror, at the sight of an object, in itself
formed to produce the illusion, and which finds in the imagination a
place already prepared for the reception of phantoms.
The instrument placed behind the gauze screen is in fact a peculiar
construction of the magic lantern: only in the former, it is
necessary that the lenses should run over a much greater space,
and that the instrument may be susceptible of approaching to,
and receding from, the frame of gauze, in such manner, that each
luminous pencil may be depicted there in a single point. The general
construction is this: In a square box, a lamp is placed, the luminous
rays proceeding from which, are reflected by a conical mirror,
towards an orifice made in the box. At this orifice is placed a tube,
blackened within, and composed of several tubes which slide one into
another, like those of a pocket telescope. This tube is furnished
with two bi-convex lenses of about five inches diameter; one of these
is fixed, the other is at the outer extremity of the tube, and is
separated from the former in proportion as the tube is lengthened by
the aid of a hooked lever situated along the tube, between the lamp
and the lenses. A groove is properly adapted to the tube, destined
to receive transparent figures; lastly, the box rests upon a table
moveable on four wheels, that slide in two channels perpendicularly
to the frame on which the images are depicted. It is manifest,
that we may augment or diminish the dimensions of the images,
and consequently make the spectre appear more or less near to the
spectator, by separating farther, or by bringing nearer together, the
two lenses; but then the focus of the diverging rays, which proceed
from the same point of the transparent body, will be no longer upon
the screen; we must, therefore, cause the machine so to recede or
approach, that the two motions, being duly combined, the image may be
distinctly formed.
These phantasmagoria are furnished with a great number of
transparencies, in each of which, several changes may be made by
slackening their springs. Thus we may change at every instant, the
form, the magnitude, and the distance of the spectres, as they appear
to the spectator.
What has been said hitherto, relates only to the images of
transparent figures. To obtain those of opaque bodies, first place
the gauze and box, at the distance of about six feet one from the
other, and adapt to the orifice of the box, an apparatus of two
tubes furnished with two bi-convex lenses. An opaque body, such, for
example, as a medal, or a picture, is attached to a little support,
posited in the middle of the box; the lamp with its supply of air,
situated in one of the foremost corners of the box, illuminates that
object, and the reflected rays, crossing the lenses, proceed till
they trace the image upon the gauze, with an amplification which is
in the ratio of the distances.
If the image be not distinct, we must infer that it is not at the
focus; but it may be adjusted in three different ways; 1. By moving
the box to or from the gauze; 2. By moving the object nearer to, or
farther from, the lenses within the box; 3. By slowly moving the
tubes, to cause a variation in the distance between the lenses.--See
Haüy's _Philosophy_, translated by Gregory, vol. ii, p. 390.
Mr. Nicholson, however, witnessed an exhibition of the phantasmagoria
at the London Lyceum by Philipstal, who took out a patent for his
improvements in the apparatus and machinery. He observes, that the
novelty consists in placing the lantern on the opposite side of the
screen which receives the images, instead of on the same side as the
spectator, and suffering no light to appear but what passes through,
and tends to form those images. His sliders are therefore perfectly
opaque, except that portion upon which the transparent figures are
drawn, and the exhibition is thus conducted.
All the lights of the small theatre of exhibition were removed,
except one hanging lamp, which could be drawn up, so that its flame
should be perfectly enveloped in a cylindrical chimney, or opaque
shade. In this gloomy and wavering light, the curtain was drawn up,
and presented to the spectator a cave or place exhibiting skeletons,
and other figures or terror, in relief, and painted on the sides
or walls. After a short interval, the lamp was drawn up, and the
audience were in total darkness, succeeded by thunder and lightning;
which last appearance was formed by the magic lantern upon a thin
cloth or screen, let down after the disappearance of the light, and
consequently unknown to most of the spectators. These appearances
were followed by figures of departed men, ghosts, skeletons,
transmutations, &c. produced on the screen by the magic lantern on
the other side, and moving their eyes, mouth, &c. by the well known
contrivance of two or more sliders. The transformations are effected
by moving the adjusting tube of the lantern out of focus, and
changing the slider during the moment of the confused appearance.
It must be again remarked, that these figures appear without any
surrounding circle of illumination, and that the spectators, having
no previous view or knowledge of the screen, nor any visible object
of comparison, are each left to imagine the distance according
to their respective fancy. After a very short time of exhibiting
the first figure, it was seen to contract gradually in all its
dimensions, until it became extremely small, and then vanished.
This effect, as may easily be imagined, is produced by bringing
the lantern nearer and nearer the screen, taking care at the same
time to preserve the distinctness, and at last closing the aperture
altogether: and the process being (except as to brightness) exactly
the same as happens when visible objects become more remote, the mind
is irresistibly led to consider the figures, as if they were receding
to an immense distance.
Several figures of celebrated men were thus exhibited with some
transformations; such as the head of Dr. Franklin being converted
into a skull, and these were succeeded by phantoms, skeletons, and
various terrific figures, which instead of seeming to recede and
then vanish, were (by enlargement) made suddenly to advance; to the
surprise and astonishment of the audience, and then disappear by
seeming to sink into the ground.
This part of the exhibition, which by the agitation of the spectators
appeared to be much the most impressive, had less effect with me than
the receding of the figures; doubtless because it was more easy for
me to imagine the screen to be withdrawn than brought forward. But
among the young people who were with me, the judgments were various.
Some thought they could have touched the figures, others had a
different notion of their distance, and a few apprehended that they
had not advanced beyond the first row of the audience.
The whole, as well as certain mechanical inventions, were managed
with dexterity and address. The lightning, being produced by the
camera, was tame, and had not the brisk transient appearance of the
lightning at the theatres, which is produced by rosin, or lycopodium
powder, thrown through a light, which in Mr. P's utter darkness might
easily have been concealed in a kind of dark lantern.
A plate of thin sheet iron, such as German stoves are made of, is an
excellent instrument for producing the noise of thunder. It may be
three or four feet long, and the usual width. When this plate is held
between the finger and thumb by one corner, and suffered to hang at
liberty, if the hand be then moved or shaken horizontally, so as to
agitate the corner at right angles to the surface, a great variety
of sounds will be produced; from the low rumbling swell of distant
thunder, to the succession of loud explosive bursts of thunder from
elevated clouds. This simple instrument is very manageable, so that
the operator soon feels his power of producing whatever character of
sound he may desire; and notwithstanding this description may seem
extravagant, whoever tries it for the first time will be surprised at
the resemblance. If the plate be too small, the sound will be short,
acute, and metallic.
We may remark also, that the magic lantern, by new contrived sliders
and machinery, may be applied to important uses, by employing it
with such figures as will explain the general principles of optics,
astronomy, botany, &c.
The experiment mentioned by Ferguson, with a concave mirror,
reflecting into the air the appearance of fire, &c. into a focal
point, (founded on a general principle of concave reflectors,) is
productive of many agreeable deceptions, and which exhibited with art
and an air of mystery, has been very successfully employed.
The phantasmascope of Walker is similar to the phantasmagoria. It
is an optical machine, which presents a door that opens itself. The
apparatus is so contrived, that, on opening the door, a phantom makes
its appearance, having all the colours of a picture, which approaches
the spectator. Various figures may be accurately represented.
We will not enlarge on this subject, although many other instances
of tricks, performed by means of fire, &c. might be noticed. We will
merely remark:
1. For the performance of these exhibitions, the ancient, as well
as the modern jugglers, of _all_ descriptions, employed, and were
acquainted with sundry mixtures, and compositions, by the use of
which, they deceived the people; and some pretended to possess
supernatural agencies. Of these compositions, with many of which we
are unacquainted, we have enumerated some, and their effects. That
of producing a callosity of the skin, &c. by means of acids, is an
example.
2. That they possessed, as a trade or profession, the arts of
deception. Not only by the use of chemical preparations, but by
other means, they pretended to work miracles in the dark ages of
science. However degraded these persons may seem, they yield in vice
to another class, who practised the art of poisoning, and who kept
it so profound a secret, that few then understood the effect of the
now common, vegetable, and mineral poisons. Who could have been more
infamous than the celebrated female poisoner, Tophania?
CHAPTER II.
OF THE SUBSTANCES USED IN THE FORMATION OF FIRE-WORKS.
_Sect. I. Of Nitrate of Potassa, or Saltpetre._
Nitrate of potassa, nitre, or saltpetre, is composed, as its name
expresses, of nitric acid, and potassa. When pure, it contains,
according to Kirwan, potassa 51.8, nitric acid 44, and water 4.2
in the hundred. This salt, when pure, or even mixed with other
saline substances, is recognised by placing it on hot coals. Slight
detonations, and a hissing noise, with a vivid combustion take place.
It is also decomposed by sulphuric acid, and the nitrous vapour is
apparent from its smell and colour.
Nitrate of potassa crystallises in six-sided prisms, terminated by
six-sided pyramids. Its specific gravity is 1.933. Its taste is sharp
and cooling. One part is soluble in seven parts of water, at the
temperature of 60 degrees, and in rather less than its own weight of
boiling water.
It melts in a strong heat, and by cooling congeals into an opaque
mass, called _crystal mineral_, or _sal prunelle_.
Exposed to a red heat, it disengages _oxygen gas_, and passes to the
state of a nitrate; at a higher temperature, this is decomposed, and
oxygen, azote, and a portion of nitrous acid, which has not been
decomposed, are evolved. What remains is potassa. When projected on
ignited coals, it burns brilliantly. Detonation also ensues by mixing
nitre and charcoal, and throwing the mixture into a red-hot crucible.
The residuum is carbonate of potassa. Fourcroy (_Système des
Connoissances Chimiques_, Tome iii, p. 124.) observes, that metals,
with nitrate of potassa, will decompose this salt, and produce
different coloured flame, extremely brilliant, on which account such
substances are used in fire-works.
The alchymists believed, they could obtain, from nitre, a liquor,
which would constitute, with other substances, the _philosopher's
stone_. The _clyssus_ of nitre, they imagined, possessed wonderful
properties. The decomposition of nitre by charcoal, they effected
in two ways, _viz._ by submitting the mixture to the action of heat
in a crucible, or, otherwise in an earthen or iron retort. In the
latter case, they collected a fluid, principally water, containing
some carbonic acid, and the aeriform product they suffered to
escape. The residue they named _nitre fixed by charcoal_, or, _the
extemporaneous alkali of nitre_. When, in the place of charcoal, a
mixture of sulphur and nitre was projected into a red-hot crucible,
they obtained a saline substance, to which they gave the name of _sal
polychrest_. This is the same as vitriolated tartar, or sulphate of
potassa, and is that salt which is formed in the distillation of
nitric acid from nitre, and sulphuric acid. The _crystal mineral_,
of some of the old pharmacopœias, was nothing more than nitrate of
potassa fused with a portion of sulphur, and, therefore, a mixed
salt, consisting of nitrate and sulphate of potassa.
Nitrate of potassa, distilled with half its weight of sulphuric acid,
furnishes nitric acid, or concentrated spirit of nitre. This, diluted
with about an equal weight of water, forms the _aqua fortis_ of the
shops.
A mixture of nitre and phosphorus, if struck with a hammer, produces
a violent detonation. Nitre oxidizes all the metals at a red heat,
even gold and platinum.
Nitre and sulphur, thrown into a red-hot crucible, produces an
instantaneous combustion, accompanied with a great disengagement of
light and heat. Sulphurous acid gas, with sulphuric acid, is produced.
Equal parts of cream of tartar, (supertartrate of potassa,) and
nitre, deflagrated in a crucible, form _white flux_. Two parts of
tartar, and one of nitre, treated in the same manner, produce _black
flux_.
Three parts of nitre, one part of sulphur, and one part of sawdust,
mixed together, form the _powder of fusion_.
When three parts of nitre, two parts of potash, and one of sulphur,
all previously well dried, are mixed together, the compound is called
_pulvis fulminans_, or, _fulminating powder_. A small portion of this
powder, or as much as will lay on a shilling-piece, put on a shovel,
and exposed to heat, will first melt, become liver-coloured, and
then explode with great noise. The theory of this explosion is, that
a part of the sulphur, and the potassa unite, and form a sulphuret;
the sulphuret then decomposes water, and produces sulphuretted
hydrogen gas, which appears to be decomposed by the nitric acid; and
there results sulphurous acid gas, water, and, as Thenard observes,
protoxide of azote, azotic gas, and sulphate of potassa. The loudness
of the report depends on the combustion of the whole powder at the
same instant, which is secured by the previous fusion it undergoes.
Gunpowder, on the contrary, burns in succession, although apparently
instantaneous. In using common potash, there is also, as the alkali
contains it, carbonic acid, given out in the state of gas. In fact
carbonic acid appears to assist the explosive effect of this powder,
for when it is prepared with potash, containing little carbonic acid,
its detonating power is considerably less.
Nitre likewise enters into the composition of another fulminating
powder, invented by Dr. Higgins. _Higgins's fulminating powder_ is
composed of three and a half parts of nitre, two parts of crude
antimony, and one part of sulphur. This is used in the same manner as
the former.
Nitre enters into the composition of gunpowder, which we shall
notice under a separate head. The proportions of nitre, sulphur,
and charcoal, for the formation of gunpowder, which are considered
the best, are, 75 parts of nitre, 12-1/2 of charcoal, and 12-1/2 of
sulphur.
The new powder of MM. Gengembrie and Bottée, which inflames by
percussion, but without explosion, is composed of 21 parts of nitre,
54 parts of chlorate of potassa, 18 parts of sulphur, and 7 parts of
lycopodium.
A mixture of nitre and crude antimony projected into a red-hot
crucible, produces a deflagration more or less rapid, forming a
composition which is used in pharmacy, and medicine.
The quality of saltpetre may be determined by a variety of
experiments. Fire-workers judge of its quality by the colour of its
flame.
The flame should be white. If it be _green_ or _yellow_, it is said
to be impure.
Nitric acid, obtained by distilling saltpetre and sulphuric acid,
has a powerful effect on inflammable substances. If nitric acid,
or in preference, the fuming nitrous acid, be poured on spirit of
turpentine, especially if it be old, it will inflame. To succeed,
however, in this experiment, a small portion of sulphuric acid is
usually added to the nitric acid. As this effect is owing to the
facility, with which the acid parts with its oxygen to inflammable
bodies, other essential oils, besides turpentine, will have the same
effect. If the same acid is poured on finely pulverized charcoal, or
on lampblack, combustion will also take place. When oils are used,
water as well as carbonic acid is produced, and when charcoal or
lampblack, carbonic acid alone. There is also a large quantity of
carbon, in the former instance, which remains on the plate, or dish.
M. Delametherie (_Journal de Physique_, 1815) has shown, that olive
oil may be converted into a substance, resembling, and having many
of the properties of, wax, by mixing it with a given proportion of
nitric acid. The acid is decomposed, deutoxide of azote is formed,
and the oil acquires a hard consistence. A candle made with this
artificial wax, he observes, burns with a clear light and without
smoke. The experiment with the _glace inflammable_ is on the same
principle.
Morey (_Silliman's Journal_, vol. ii, p. 121.) states a singular
experiment, in which nitre is used; _viz_: If to tallow or linseed
oil, a small quantity of saltpetre be added, and the temperature
raised to nearly that of the boiling point, the saltpetre appears
to be dissolved by the oil; they will _evaporate together_, and
the mixture, or the vapour, will burn, _wholly excluded from the
atmosphere_.
Saltpetre was one of the substances employed by the alchemists. It
appears from the memoir of Geoffroy, (_Coll. Academ._ 1722,) that the
object of the alchemists was twofold; the transmutation of metals,
and particularly what were denominated the _baser_ metals into the
precious, which they pretended to effect by a _universal spirit_, the
_grand elixir_, the _philosopher's stone_, &c. and the reduction of
metals to their _earths_. Alchemy was introduced into Europe by the
crusaders, and it is remarkable, that, in the reign of Henry IV,
an act was passed to make it felony to transmute metals. Mr. Boyle,
aware of its absurdity, suggested the propriety of repealing that
act, which was done. One of their powders was composed of nitre,
cream of tartar, and sulphur.
_Preparation._ Although nitrate of potassa is generated in
abundance, particularly in the East, yet in all countries, where
the circumstances are favourable to its production, it is found. It
never occurs, native, in very large masses. It is generally found
in an efflorescence, on the surface of the soil, or in caverns. It
never exists in the soil more than a few yards beneath the surface.
We may remark, that native nitre has never been found in pure clay,
or pure sand, except in the _rock-ore_, as it is called, of the
western United States. It is often found in caverns, and fissures in
calcareous rocks.
In the East Indies, the districts which furnish saltpetre, are swept
at certain seasons of the year. This is repeated two or three times a
week; for the saltpetre again appears in the same places, in the form
of efflorescence.
It is supposed that some countries furnish saltpetre, in consequence
of the drought, which continues for some time. At Lima, M. Dombay
informs us, there is seldom rain; and the fields, which serve as
pasturage for beasts, are so much covered with saltpetre, as to be
removed with the spade. There must then be a rapid formation of
nitre. M. Talbot observes, that in the meridional provinces of Spain,
the earth frequented by animals, contains it, ready formed. When
saltpetre became an article of importance, the rulers of Germany, &c.
justified themselves in exclusively carrying away the incrustations
of walls from private houses, which, when it could be used, became
_accessorium fundi_. Accordingly this _regale_, as it was called, was
extended every where, and was generally unpopular. In 1419, Gunther,
archbishop of Magdeburgh, issued the first grant, which was the right
of searching saltpetre and boiling it, during a year, in the district
of Gibicherstein, for which the person, to whom it was granted, was
to pay a barrel of saltpetre, and deliver to the archbishop the
remainder at a certain price.
The succeeding archbishop, Frederick, let, in 1460, to a burgher of
Halle, all the earth and saltpetre that could be collected in the
bailiwick of Gibicherstein, for four years, at the annual rent of a
given quantity of refined saltpetre. Bishop Ernest, in 1477, let, for
his time, the privilege of collecting saltpetre. In 1544, saltpetre
was collected, in the same manner, from the rubbish before the
gates of Halle; and in the year following, the magistrates of Halle
erected a powder mill, and had saltpetre works. John VI, archbishop
of Triers, granted similar privileges in 1560. The saltpetre regale,
was long known, and confirmed by a Brandenburgh decree in 1583.
Old walls, and the vicinity of stables, frequently exhibit saltpetre
in the state of efflorescence. It was the ancient _scrophula contra
lapides_, represented as a kind of leprosy. For the spontaneous
production of nitre, animal and vegetable substances, in a state of
decomposition, and the presence of dry atmospheric air are necessary.
That lime, and the calcareous carbonates also promote its formation,
there can be no doubt.
Notwithstanding the large quantity of saltpetre collected in the East
Indies, we are told, that two-thirds of the whole are annually sent
into China, and other parts of Asia, to make artificial fire-works.
The pyrotechny of the Chinese is said to be very perfect; in variety
and beauty, some writers assert they exceed all other nations. There
is a natural nitre bed at Apulia, near Naples, which affords 40
per centum of nitre. Pelletier, (_Ann. de Chim._ tome xxii.) has
published an analysis. The cavity of Molfetta is one hundred feet
deep, containing grottos or caverns. Nitrate of potassa is found
in the interior, in efflorescence or crusts, attached to compact
limestone. On removing these efflorescences, others appear. The soil
in this cavity is richly impregnated with nitre.
In Switzerland, the farmers extract an abundance of saltpetre from
the stalls under their cattle. During the American revolution, when
every expedient was resorted to, to obtain a supply of this article,
the floors of tobacco houses, &c. were dug up and lixiviated. In the
reign of Charles the First, certain patentees were authorised to dig
up the floors of all dove-houses, stables, &c. the floors being again
laid with mellow earth.
The Ukraine, Podolia, Hungary, Spain, Italy, Peru, and India, furnish
more or less of this salt, which is extracted by lixiviating the
earths that compose the soil. The springs, in particular districts of
Hungary, contain it.
We are informed, (_Ann. de Chim._ xx. 298,) that, during the second
and third years of the French Republic, the government required
every district to send two intelligent young persons to Paris. This
convocation, consisting of nearly eleven hundred persons, received
regular instruction from their first chemists, partly concerning
the manufacture of cannon, and partly respecting the manufacture
of saltpetre and gunpowder. This body of pupils was afterwards
distributed among the different establishments in proportion to their
abilities, and saltpetre was soon furnished in abundance.
In the United States, we have an abundant source of saltpetre in
the _nitre caves_ of the western country. There is now no occasion
for lixiviating the soil of tobacco houses, or of stables, or the
refuse of old buildings, the preparation of artificial nitre beds, as
adopted in France, or for any other expedient, to furnish a supply
of saltpetre; these caverns, which are calcareous, producing it
in great abundance. The _earth_ of these caves does not, however,
contain pure nitrate of potassa, but generally a mixture of this
salt and nitrate of lime, a calcareous nitrate which constitutes the
principal part. The latter is changed into nitrate of potassa, as we
shall observe more particularly hereafter, by making a lixivium of
the earth in the usual manner, and passing it through wood ashes. The
alkali, which the latter contains, decomposes the nitrate of lime, by
uniting with the nitric acid; hence the fluid, which passes through,
is nitrate of potassa or saltpetre. This is evaporated, and suffered
to crystallize. It is then the _crude, or rough nitre_, which is
purified, principally by re-solution, and crystallization.
The saltpetre makers, at the caves, have found, that two bushels
of ashes, made by burning the dry wood in hollow trees, afford as
much alkali as eighteen bushels of ashes obtained from the oak.
Notwithstanding the _nitre earth_ contains a mixture of the nitrates
of potassa and lime, nitrate of potassa, nearly pure, has been
discovered. It is sometimes found in the fissures of sandstone, or
among detached fragments. Some of these masses are said to weigh
several hundred pounds.
Besides these caverns, which have been accurately described by Dr.
Brown, in the Transactions of the _American Philosophical Society_,
(vol. v, vi.) similar caverns have been discovered in Tennessee,
and in some parts of Virginia and Maryland. At Hughes' cave near
Hagerstown, in Maryland, this salt has also been made.
We are of opinion, that most of the calcareous caverns in the United
States, if carefully examined, might be found to contain nitre, or at
least, the calcareous nitrate, which is readily converted into nitre
by lixiviation with wood ashes, or the addition of a due quantity of
potash.
Professor Cleaveland, in noticing the saltpetre caves of the
western country, observes, (_Elementary Treatise on Mineralogy and
Geology_,) that one of the most remarkable of these caverns is
in Madison county, on Crooked Creek, about sixty miles S. E. from
Lexington. This cavern extends entirely through a hill, and affords a
convenient passage for horses and wagons. Its length is six hundred
and forty-six yards; its breadth is generally about forty feet; and
its average height, about ten feet. One bushel of the earth of this
cavern, commonly yields from one to two pounds of nitre; and the same
salt has been found to exist, at the depth of at least fifteen feet;
even the clay, a fact which seems rather remarkable, is impregnated
with nitrate of lime. Kentucky also furnishes native nitre under a
very different form, and constituting what is there called the _rock
ore_, which is in fact a sand stone, richly impregnated with nitrate
of potassa. These sand stones are generally situated at the head of
narrow vallies, which traverse the sides of steep hills. They rest on
calcareous strata, and sometimes present a front from sixty to one
hundred feet high. When broken into small fragments, and thrown into
boiling water, the stone soon falls into sand; one bushel of which,
by lixiviation and crystallization, frequently yields ten pounds, and
sometimes more than twenty pounds of nitrate of potassa. The nitre
from these rocks contains little or no nitrate of lime. This account
is corroborated by Dr. Brown,[13] to whom our author is indebted for
his remarks.
In a memoir in the American Philosophical Transactions by Dr. Brown,
then of Lexington Kentucky, we have a description of a nitre cave
on Crooked Creek, with the process for extracting the saltpetre.
From this memoir, the following extracts are made: The water which
percolates through the cave in summer, as the walls and floor are dry
in winter, condenses upon the rocks, and the substance thus formed,
has the same properties as the salt obtained by lixiviating the earth
of the floor. As far as the workmen have dug, the earth is strongly
impregnated, every bushel of which, upon an average, furnishes one
pound of nitre. The same earth will be again impregnated, if thrown
into the cave. What length of time it requires to saturate it, is not
known.
The workmen have different modes of forming an opinion with regard
to the quantity of nitre, with which the earth may be impregnated.
They generally trust to their taste; but it is always considered as
a proof of the presence of the nitre, when the impression made one
day on the dust by the hand or foot disappears the day following.
Where there is a great deal of sand mixed with the dust, it is
commonly believed that a small quantity of potash will suffice for
the operation. The method of making saltpetre, usually practised in
Kentucky, is as follows:
The earth is dug, and carried to hoppers of a very simple
construction, which contain about fifty bushels. Cold water is poured
on it for some time, and in a day or two, a solution of the salts
runs into troughs placed beneath the hoppers. The lixiviation is
continued as long as any strength remains in the earth. The liquor
is then put into iron kettles, and heated to ebullition; it is
afterwards thrown upon a hopper containing wood ashes, through which
it is suffered to filtrate. As the alkaline part of the ashes is
discharged before the nitrate passes through, the first runnings of
this hopper are thrown back, and after some time, the clear solution
of nitrate of potassa runs out, mixed with a white curd, which
settles at the bottom of the trough. This clear liquor is boiled to
the point of crystallization, then settled for a short time, and put
into troughs to crystallize, where it remains twenty-four hours;
the crystals are then taken out, and the mother water thrown upon
the ash hopper, with the next running of the nitrate of lime. When
the quantity of the nitrate of lime is too great for the portion of
ashes employed, the workmen say their saltpetre is in the _grease_,
and that they do not obtain a due quantity of nitre. If too much
ashes are used, they say it is in the _ley_; and when it is left to
settle previous to crystallization, a large quantity of salt will be
deposited in the settling troughs, which they call _cubic salts_.
These salts are again thrown upon the ash-hoppers, and are supposed
to assist in precipitating the lime from the nitrate of lime, and
in the opinion of the workmen are changed into pure saltpetre. To
make a hundred pounds of good saltpetre at the great cave, eighteen
bushels of oak ashes are necessary; ten of elm, or two of ashes made
by burning the dry wood in hollow trees. The earth in some caves does
not require half this quantity of wood ashes to decompose the earthy
salts.
When wood ashes cannot be obtained in sufficient quantity, they make
a lixivium of the earth, and boil it down, which they call _thick
stuff_. This is put in casks, and transported to a place where ashes
can be had. When dissolved and passed through wood ashes, it is
changed, as in the former process, into saltpetre. Having thus given
the Doctor's account, let us inquire, in the next place, into the
theory of the process.
The theory is very evident. The mixed nitrate, consisting of variable
proportions of nitrate of lime and nitrate of potassa, is extracted
from the saltpetre earth by water, which dissolves it. Now, as
the affinity of nitric acid for potassa is greater than for lime,
and consequently potassa will decompose nitrate of lime, when the
lixivium is passed through wood ashes, the potassa they contain
will unite with the nitric acid, and the lime be separated, which
remains in the hopper. The liquor holds in solution no other salt
than nitrate of potassa, provided the quantity of alkali in the wood
ashes be sufficient to effect the decomposition;--if _more_, it will
pass through in an uncombined state; and if _less_, the liquor will
contain nitrate of lime. As the alkali contains more or less carbonic
acid, the decomposition is not a case of single but of double
affinity, in which we form, at the same time, a carbonate of lime.
When the solution is boiled, and set aside in the troughs to
crystallize, the nitre will form in a regular manner. The mother
water, or the fluid which remains after the crystallization, may
contain, from the circumstance before stated, either potash, or
undecomposed nitrate of lime--hence it is thrown on the hopper in a
subsequent operation.
The nitre, however, as made at the caves, is called _rough_ or crude
nitre. Before it is used for the manufacture of gunpowder, and other
purposes, it is purified or refined. This operation, which we shall
notice more fully hereafter, is nothing more than the separation of
all earthy salts, and the alkaline muriates and sulphates; in other
words, the conversion of the whole by the separation of foreign
substances, into pure nitrate of potassa.
The mode of treating the _rock ore_, or sand rocks, which contain
nitre, is the same as before given. It contains more nitrate of
potassa, and therefore requires less potash, and in some instances,
the nitre is perfectly pure. The sand rocks often yield twenty or
thirty pounds per bushel. A mass of pure nitre, weighing sixteen
hundred pounds, has been discovered. Smaller masses have also been
found.
The rocks which contain the greatest quantity of nitre are extremely
difficult to bore, and are tinged brown or yellow.
Saltpetre makers find it to their interest to work the rock ore in
preference to the calcareous nitrate, as it yields more nitre.
It is a fact well known, that foreign saltpetre contains a variety of
deliquescent salts, or those salts which attract and absorb moisture
and also common salt. The efforts of European refiners are directed
to their separation. The saltpetre of the Western country, Dr. Brown
assures us, does not contain common salt.
Dr. Brown, in _Silliman's Journal_, i, p. 147, in a letter to
professor Silliman, observes, that there exists a black substance in
the clay under the rocks, of a bituminous appearance and smell. This
black substance, it appears, accompanies the sand-rock nitre, and is
the same as that found in Africa, which also accompanies nitre in
that country. Animal matter seems to have existed in the nitre caves
of Africa, forming, as Mr. Barrow expresses it, either a _roof_ or
covering; no such matter, however, has ever been found in or adjacent
to the nitre caves of the Western country.
The observations of Mr. Barrow on the subject of the saltpetre of
Africa may be interesting to the reader. He observes, (_Southern
Africa_, p. 291,) that, about twelve miles to the eastward of the
wells, (_Hepatic Wells_), in a kloof of the mountain, we found a
considerable quantity of native nitre. It was in a cavern similar
to those used by the Bosgesmans for their winter habitations. The
_under surface_ of the projecting stratum of calcareous stone, and
the sides that supported it, were incrusted with a coating of _clear,
white saltpetre_, that came off in flakes. The fracture resembled
that of refined sugar; it burnt completely without leaving any
residuum; and if dissolved in water, and thus evaporated, crystals
of pure _prismatic nitre_ were obtained. This salt, in the same
state, is to be met with under the sand-stone strata of many of
the mountains of Africa. There was also in the same cave, running
down the sides of the rock, a black substance, that was apparently
bituminous. The peasants called it the urine of the das. The dung of
this _gregarious_ animal was lying upon the roof of the cavern to the
amount of many wagon loads.
The Rev. Mr. Cornelius, in describing a cave in the Cherokee country
at Nicojack, the north west angle in the map of Georgia, (_Silliman's
Journal_, vol. i, p. 321,) observes, that it abounds with nitrate
of potassa, a circumstance very common to the caves of the Western
country, and is found covering the surfaces of fallen rocks, but
in more abundance beneath them. There are two kinds; one is called
the "clay dirt," the other the "black dirt." The earth, however,
contains calcareous nitre, and for that reason an alkaline lixivium
is employed. In short, the process employed there is the same as at
the other saltpetre caves which we have described. One bushel of the
clay dirt yields from three to five pounds of nitre, and the black
dirt from seven to ten pounds. It seems also, that the same dirt, if
carried back to the cave, will become impregnated with nitre.
Mr. Cornelius remarks, that these caves have been used by the
natives as burial places; in one of which he counted a hundred human
skulls in the space of twenty feet square; and infers, that, by the
decomposition of animal matter, the acid of nitric salts arises, and
therefore that this may have occasioned the formation of the nitrates
of potassa and lime.
At Corydon, in Indiana, there is a cave, which, according to
Stilson's account, contains both nitrate of lime, and nitrate of
magnesia. It is not worked.
Kain, in his remarks on the Geology and Mineralogy of East Tennessee,
(_Silliman's Journal_, vol. i, p. 65,) observes, that the numerous
caves which have been found in the Cumberland mountains, and
other parts of Tennessee have been very productive of nitrate of
potassa; and in confirmation of the remarks before made, he adds, in
investigating the causes that have given rise to these salts, that
wild animals burrow in these caves; that, when pursued by the hunter,
they make them the places of their retreat, and probably die there;
that the aborigines have made them a place of burial; and that the
streams of water, which flow through them, in wet weather, carry with
them not only great quantities of leaves, but many other vegetable
productions.
Without offering any theory, by which we may account for the
formation of nitre, in nitre caves, or in situations which cannot
be influenced by the putrefactive process, we may merely remark,
that as nitric acid is composed of oxygen and azote, there must be
some operation unknown to us, by which the union of these elements
takes place. Nascent azote must unite with the base of oxygen gas;
but whence, in saltpetre caves, proceeds the azote and the oxygen?
It appears that calcareous bodies facilitate the formation of nitre,
as they do in artificial nitre beds. The greater part of the nitrous
earth is lime; and it also appears, that the same earth, after the
extraction of the saltpetre, will again furnish it. We know that lime
is a compound of a base called calcium united with oxygen; but in
what manner it promotes the union of azote and oxygen, or furnishes
either one or the other of these bodies, or perhaps both, is
altogether uncertain. Nor can we account for the formation of potash
in the native nitre of the nitre caves. In other situations, as for
instance where nitrous efflorescence appears on the earth, and in
artificial nitre beds, in which animal and vegetable substances are
in the act of decomposition by the putrefactive fermentation, we may
account for the generation of nitric acid.
It is extremely probable, that the azote of the atmosphere, and
oxygen may combine spontaneously, under particular circumstances, in
various operations of nature. Azote, it is known, forms with oxygen
two gases, a protoxide and deutoxide, and the same elements in other
proportions form nitric acid. Some condition, unknown to us, must,
as an operating cause, produce this compound. As a condition for its
generation, the presence of calcareous and alkaline matter, favours
the formation of nitric acid. Of this fact, we have sufficient
proof, in the generation of nitre in artificial nitre beds. But,
with respect to natural causes, although the facts themselves are
conclusive, we know little or nothing.
Atmospheric air is a mixture, or compound, according to some, of
two gases, oxygen and azote, with carbonic acid; but the proportion
of the latter rarely exceeds two per cent, while the quantity of
oxygen is about twenty-two. It is a solvent, as well as a vehicle,
and hence may contain water, gaseous fluids, &c. Miasmata, which is
contained often in the air, are vapours or effluvia, that affect the
human system, and bring on diseases, of which the principal are the
intermittent, remittent, and yellow fevers, dysentery and typhus.
That of the last is generated in the human body itself. The same, or
analogous causes, that produce the formation of nitric acid, may,
under other circumstances, cause the formation of miasmata; for moist
vegetable and other matter, in some unknown state of decomposition,
generates it, and is known to have caused the yellow and other
malignant fevers. (See an admirable work on the _causes, &c. of the
yellow fever in Philadelphia_, by SAMUEL JACKSON, M. D. president
of the board of health, etc. in reply to the observations of Dr.
Hosack.) The contagious _virus_ of the plague, small pox, etc. as it
operates in a more limited distance than marsh, or other miasmata, is
communicated only in certain localities, and through the intermedium
of the atmosphere. As to the chemical nature of miasmata, there can
be no doubt that azote, under some form of combination, is one of its
component parts, and one of the causes of disease. Is not cyanogen,
or carburet of azote, perhaps combined with hydrogen, in the form of
hydrocyanic or prussic acid, the substance, or _principal_ substance,
which forms the miasmata, that engenders the yellow fever? What
compounds may be formed of hydrogen, sulphur, phosphorus, carbon, and
_azote_, so as to produce miasmata, that will act specifically on the
system for the production of intermittent, remittent, yellow, typhus,
and other fevers?[14] This inquiry, permit me to add, is one of no
small moment, as it involves in it a question of great importance
relative to the origin of yellow fever. While we thus digress,
in noticing the compounds of azote, let us briefly remark, as an
indisputable conclusion, that the same causes of malignant disease
in the West India islands, operating under similar circumstances in
every respect, may engender the same disease in our cities.
The atmosphere is subject to changes of various kinds, and may be
considered not only as a solvent, but a repository for different
foreign bodies. Electricity, an agent so essential in the economy
of nature, has its ends, its uses; and while, no doubt, it unites
hydrogen with oxygen, in the most elevated regions of the air, and
forms water, it may act under particular circumstances to produce
a union of azote and oxygen so as to generate nitric acid. Dr.
Priestley, (_Transactions of the American Philosophical Society_,)
detected nitric acid in snow. But of all atmospheric phenomena, the
formation of meteorolites, or meteoric stones, is the most wonderful.
If they be really formed in the atmosphere, there can be no doubt,
that the elementary principles which compose them must exist in
it; and that the phenomenon denominated meteoric, in such cases,
is no other than the operating cause, by which meteoric stones are
generated.[15]
Animal substances furnish azote, as it is one of their constituent
parts; and in the act of its separation, by uniting with oxygen,
principally furnished by the air, it forms nitric acid; which,
attaching itself to the alkali of the vegetable matter, or the lime
usually added to nitre beds, or to other salifiable bases, forms
either nitrate of potassa, nitrate of lime, or a nitrate of the
particular base. The lixiviation of the nitrous substances, and the
use of wood ashes, or potash itself, will produce saltpetre.[16]
Brongniart has given the following process for purifying or refining
saltpetre: Pulverize the impure nitre, and wash it three times in
cold water, in the proportion of 35 lbs. of water, to 100 lbs. of
the salt, taking care to pour off the water before another portion
is added. These washings separate the greater part of the muriate
of soda, and the deliquescent salts, such as nitrate of lime. When
thus washed, the nitre is to be dissolved in half its weight boiling
water. On cooling, the salt begins to crystallize, and, by agitating
the liquid during the process, minute crystals are obtained. These
crystals when dried are to be washed in 5 lbs. of cold water for
every 100 lbs. of the salt, and then dried in a temperature of
forty-five degrees.
In India, where nitrate of lime also occurs, but in situations
different from those in the United States, the natives extract the
saltpetre by a process similar to that we have described. They refine
it by solution in water, evaporation, and crystallization. In
France, the potash of commerce is used; and the nitrates which are
decomposed, are those principally of lime and magnesia.
According to the analysis of M. Pelletier, and the experiments of
professor Vaizo, in 1781, they found the calcareous earth of the cave
at Naples, to contain forty or forty-two to the hundred, of nitrate
of potassa. (See _Annales de Chimie_, tome 23.)
In 1792, M. Pickel announced the discovery of native saltpetre, in
a quarry in the neighbourhood of Wurtzburgh. M. de la Rochefoucald
discovered nitre in the neighbourhood of chalk in France, in the
departments of Seine and Oise. MM. Lavoisier and Clouet, made a
number of researches with the same view. Since that time, saltpetre,
or nitrous earth has been found in several of the departments of
France; and it appears reasonable to conclude, that in all situations
favourable to the generation of nitre, where the same causes operate,
nitre must occur in more or less abundance.
From the rubbish of old buildings, saltpetre is obtained in some
quantity. Old plaster is said to give five per cent. The soluble
salts it contains, are six in number, viz: nitrate and muriate of
lime, nitrate and muriate of magnesia, and nitrate of potassa, and
muriate of soda. Now it is obvious, that besides the decomposition
of the earthy nitrates, the earthy muriates also are decomposed by
the potash, leaving in solution, besides muriate of soda, if it is
not decomposed, by the potash, (which has this effect,) muriate, as
well as the nitrate of potassa. To refine the saltpetre prepared in
this manner, consists in separating the muriates. The proportions, in
which these salts are to each other in a hundred parts, are stated
by Thenard, (_Traité de Chimie_, Tome ii, p. 485,) to be ten,
nitrate of potassa, seventy, nitrates of lime and magnesia, fifteen,
marine salt, and five, muriates of lime and magnesia.
The mode of extracting saltpetre, and the various processes which
have been adopted for refining it, in France, and on the continent
generally, have but one object,--that of lixiviating the substances
which afford it, and subsequently, separating all foreign salts. The
best memoir was written by count Chaptal, occupying forty-seven pages
in the _Annales de Chimie_, tome xx. In this he explains the theory
at large. In the same work, tome xxiii, there is also a paper by
Guyton, and many other memoirs of the same character. In Chaptal's
_Chimie Appliqué aux Arts_, tome iv, p. 119, in Thenard's _Traité
de Chimie_, tome ii, p. 485, and in the _Annales de Chimie et de
Physique_, tome v, p. 173, the subject is ably treated.
We will now give the process of extracting saltpetre from the rubbish
of old buildings, principally plaster, as adopted in France. The
lixiviation, in the first place, is performed in the following
manner: a certain number of casks or tubs, thirty-six for instance,
is placed in three ranges. These tubs are pierced laterally near
their bottom, by a hole of about half an inch in diameter, and
closed with a cork; they are placed above a trough connected with
a reservoir. There is put then into each tub a bucket full of the
plaster, previously pounded, which is supported in the casks by cross
sticks, a certain distance from the hole, so as not to obstruct the
passage of the fluid. After this, a bushel of wood ashes is added,
and the tubs are then filled with the plaster. Water is then put
into the tubs of the first row, and after some time, the stop cocks
are turned; water is then put into the tubs of another row, and
the lixiviation is continued until the fluid indicates the zero of
Beaumé's areometer. The saline waters, which are thus obtained, are
divided into three parts, in proportion to their specific gravity, or
quantity of salt they contain. The lixivium, of five degrees of the
areometer, is known under the name of _eaux de cuite_. The waters,
which are marked between three and five degrees, take the name of
_eaux de forte_; and those below three degrees are called _eaux
faibles_. According as the waters are weak, they are made to run
through another range of tubs, in order to saturate them.
When strong and weak solutions are made to pass through the tubs in
the same manner, proceeding from the second row to the third, and
from the third to the first, the _earths plaster_, &c. being renewed,
the lixiviation is not interrupted.
The lixiviation, it appears, is thus continued; for we obtain, at the
same time, _weak waters_ from the second row, the _strong waters_
from the third, and the _boiling waters_, or those fit to be put into
the boilers, from the first.
When a sufficient quantity of the strong solution is obtained,
it is put into the copper, or boiler, and evaporated. During the
evaporation, there is a scum formed, and sundry earthy substances,
in the form of a mud, are deposited. This is usually caught in a
vessel placed in the boiler, which is raised from time to time, by
means of a rope, moved through a pulley, and fastened to a chain from
the handles of the vessel. The solution is concentrated until it
indicates the strength of twenty-five degrees of Beaumé's areometer.
It is then mixed with the mother water of the preceding boiling, and
a concentrated solution of the potash of commerce is added, until
the precipitation ceases. The sulphate of potassa may be used for
the same purpose, at least to decompose the nitrate of lime; but it
must be used in the first instance, and the operation finished in
the common way, by the addition of potash. The precipitation being
finished, that is to say, the nitrates of lime and magnesia, being
transformed into nitrate of potassa, the hot liquor is then carried
in a large tub, called the _reservoir_, and placed on the edge of the
boiler. As soon as the insoluble salts, which the solution contains,
are deposited there, which takes place immediately, the liquor is
drawn off clear by cocks, which are adapted to the tubs, and received
into the boiler, previously cleaned. The deposite obtained in the
boiling, is washed with a certain quantity of the solution, which
becomes clear, and is then mixed with the preceding liquor.
From what has been said, the liquor must contain a great quantity
of nitrate of potassa, a small quantity of the salts of lime and
magnesia, and all the marine salt contained in the plaster. It is
frequently the case, that the liquor contains muriate of potassa, and
a small quantity of sulphate of lime. It is, therefore, submitted
again to evaporation. When it is at the forty-second degree of
concentration, some part of the marine salt separates, which rises to
the surface, and is taken off, and drained through an osier basket
placed over the boiler. The solution being concentrated to the
forty-fifth degree of the hydrometer, it is put into copper vessels,
in which, by cooling, it crystallizes. The salt is then separated
from the mother water, drained and coarsely bruised, and afterwards
washed in a certain quantity of the _first boiling_. It is now in a
state to be delivered to the central administration, under the name
of crude saltpetre, or saltpetre of the first boiling.
The crude saltpetre contains about seventy-five per cent of nitrate
of potassa. The quality may be determined by treating it with a
saturated solution of pure nitrate of potassa, which cannot dissolve
any more of the nitrate, but will dissolve any foreign salts. The
twenty-five parts of the foreign substances, contained in the crude
saltpetre, are composed of a large quantity of marine salt, and of
a small portion of muriate of potassa. It is necessary to separate
them, and other foreign substances. The operation for this purpose,
is called the _refining of saltpetre_.
The refining of saltpetre is founded principally upon the property,
which nitre has, of being more soluble in warm water, than the
muriate of soda, and muriate of potassa. Thirty parts of saltpetre,
and six parts of water are put into a boiler and the liquor is
heated. By this means, there is precipitated a large quantity of
marine salt mixed with muriate of potassa. A small quantity of water
is added from time to time, to keep the nitre in solution.
When the foreign salt is not fully deposited, the liquor is
clarified, and more water is added, sufficient to form ten parts,
including that which has already been poured upon it. The liquor
is removed, when it is clear and less heated, and put into copper
vessels, where it is agitated to prevent crystallization, and to
effect the pulverization of the saltpetre.
The saltpetre obtained by this process is not sufficiently pure.
The purification is completed by washing it with water saturated
with nitre, which dissolves the foreign substances. This washing is
completed in a vessel, the bottom of which has been pierced with
holes. The nitre, however, is left some hours in contact with the
water, when the latter is permitted to run out. When the solution is
of the same degree of concentration as that of the saturated water,
the operation is finished. The nitre is dried for use.
The old process of refining saltpetre is thus described: Put into a
copper, one hundred pounds of nitre, and fourteen gallons of water;
let it boil gently half an hour, removing the scum as it forms; then
stir it, and before it settles put it into filtering bags, which must
be suspended from a rack. Put under the filters glazed earthen pans,
to receive the liquor; in which place sticks for the crystals to form
on. In two or three days, it will all crystallize.
In some saltpetre works, sulphate of potassa is used with advantage.
This salt is furnished in abundance, by the combustion of a mixture
of nitre and sulphur, in the manufacture of oil of vitriol. It
forms the residue after the combustion. It is likewise produced in
the preparation of nitric acid, in the decomposition of nitrate
of potassa, by sulphuric acid. It may, therefore, be obtained in
quantity, from the oil of vitriol manufacturers, and the aquafortis
distillers. It is usually called _vitriolated tartar_.
It is known that sulphuric acid forms, with lime, an almost insoluble
compound, called sulphate of lime, or gypsum; and hence, when
sulphate of potassa is mixed with a solution of nitrate of lime,
nitrate of potassa is formed, which remains in solution, and sulphate
of lime is precipitated. The same effect takes place with all earthy
nitrates. For the application of sulphate of potassa, in this way, we
are indebted to M. Berard. It might be advantageously employed in
decomposing the calcareous nitrate of the nitre-caves of the western
country.
M. Longchamp has recommended the use of sulphate of soda, or
Glauber's salt, for decomposing the muriate of lime, which exists
occasionally in impure nitre. These two salts reciprocally decompose
each other; sulphate of lime is precipitated, and muriate of soda
remains in solution. The latter is separated by evaporating the
nitrous solution.
M. de Saluces (_Mémoire de l'Académie des Sciences de Turin,
Année, 1805 à 1808_,) has proposed a new process for purifying
nitre. It consists in filtering it through argillaceous earth, or
clay. Although the process is highly spoken of, yet we can see no
particular advantage it possesses.
Chaptal observes, that the process mostly in use is that of
dissolving 2000 pounds of crude saltpetre in a copper boiler, in 1600
lbs. of water. As the solution is made by the heat, the scum, which
forms, is taken off. Twelve ounces of glue, dissolved in ten pints of
boiling water, and mixed with four pails full of cold water, are then
added. This addition cools the solution. As to the manipulations of
the process, they have been given. The principal thing to be attended
to, is to separate the marine salt, which is done during the boiling.
To pass this saltpetre through a second operation, in order the
more to purify it, it is again dissolved, in the proportion of 2000
pounds, in one-fourth of its weight of water. Heat is applied. The
scum is separated; a solution of 8 ounces of glue in one or two pails
full of water is then added. After the solution becomes clear, it
is suffered to cool, and at the expiration of five days, it will
crystallize, or form in a mass, which is then exposed to the air six
or eight weeks to become completely dry.
In treating of the formation of nitre in France, Bottée and Riffault
(_Traité de l'Art de Fabriquer la Poudre à Canon_,) consider it under
the following heads:
1. _The constituent principles of nitre; its generation, and the
theories respecting it._ In this article, the composition of nitric
acid and its union with potassa, and the production of artificial
nitre, are taken into view.
2. _Nitrous earths, and substances which yield saltpetre._ This
subject comprehends a view of the substances, which contain
saltpetre, as well as those which afford it by nitrification.
3. _The preparation of the substances to produce saltpetre._ This
article relates to the manipulations required for the production of
nitre.
4. _The manner of lixiviating saltpetre earths._ The lixiviation is
an important part of the process, however simple it may appear; as
upon its accuracy depends the quantity of the product.
5. _The treatment of the different waters (lixiviums) with potash,
sulphate of potassa, and wood-ashes._ This article points out the use
of potash in decomposing the earthy salts, such as nitrate of lime;
of sulphate of potassa, which converts the nitrate of lime by double
decomposition into nitrate of potassa, the sulphate of lime being
precipitated; and of wood-ashes, which act in the same manner as
potash, as they contain this alkali.
6. _The evaporation of saltpetre waters, and the crystallization of
nitre._ In this article, they consider the separation of foreign
alkaline salts, as muriate of soda, and the crystallization of the
nitre, to obtain it in a state of purity.
7. _The treatment of the mother water of crystallization._ This
article refers to the manner of using the mother water, in order to
obtain more nitre from it, and its employment in lieu of fresh water
for other lixiviums.
8. _The refining of saltpetre by the old process._ They describe here
the old process, in which a variety of substances were used to purify
the saltpetre, but which is now generally abandoned, or laid aside.
9. _The process of refining saltpetre, as adopted in the
establishments of the administration._ Under this head they give, in
detail, the process employed throughout France, as uniform and the
same, in every refinery.
10. _The manner of proceeding in the examination of various kinds
of saltpetre in the magazines of the administration._ This article
relates to the different modes of examining saltpetre.
11. _On the manufacture of potash and pearlash._ This subject is
important, as potash is an indispensable article in the preparation
of saltpetre, and the formation of the alkali may be considered as of
primary magnitude in establishments, conducted upon so large a scale
as those of France.
It is thus, that a regular system is adopted, by the French
government, for the production of saltpetre; and we may add also, for
the manufacture of gunpowder, which we notice in that article.
It may be proper to mention some facts, respecting the formation of
nitre-beds, and the means adopted, in this way, to obtain saltpetre,
and to offer, at the same time, some observations on this mode of
obtaining nitre.
The _Mémoires de l'Académie des Sciences_, 1720, contain the
observations of M. Bouldoc, relative to the process of lixiviating
saltpetre earths. Lacourt published a pamphlet some years after,
entitled, _Instruction concernant la Fabrication du Saltpetre_.
Various dissertations appeared on the same subject. In 1775, the
French Academy of Sciences proposed a prize-question, which produced
a more thorough investigation. The Memoirs of Thouvenal, of the
Chevalier de Lorgna, and of MM. de Chevrand, and Ganivel, were
highly approved, some of which took the prize. Chaptal, who has done
more, perhaps, than any other person in France, to promote this
all-important object, published, in 1794, an excellent dissertation,
founded on experiment and observation. This Memoir was published in
the _Journal des Arts et Manufactures_, t. iii, p. 12.
Kirwan (_Geological Essays_, p. 143,) remarks, that the saline crust,
which is found on the walls of the houses of Malta, is owing to
the walls being built of fine grained limestone. When wetted with
sea-water, it never dries. The crust is nitrate of potassa, nitrate
of lime, and muriate of soda, and is some tenths of an inch thick.
Under this crust, the stone moulders into dust. When the first falls
off, it is succeeded by a second, and so on, until the whole stone
is destroyed. This particular effect, however, is attributed to the
presence of marine salt.
Mr. Kirwan observes, that, "M. Dolomieu shows, at the end of his
Tract on the Lipari Islands, that the atmosphere of Malta, in some
seasons, when a south wind blows, is remarkably fouled with mephitic
air; and, at other times, when a north wind blows, remarkably pure;
and hence, of all others, most fit for the generation of nitrous
acid." Mr. Kirwan remarks, "How the alkaline part of the nitre,
which is one of the products resulting from the decomposition of
this stone, is formed, is as yet mysterious: Is it not from the
tartarin lately discovered in clays and many stones?" He adds, after
speaking of animal and vegetable decomposition, "I should rather
suppose, that the alkali is conveyed into these earths by the putrid
air, than newly formed; and the reason is, that tartarin, (potash,)
notwithstanding its fixity, is also found in soot; and, in the same
manner, may be elevated in putrid exhalations."
Artificial nitre-beds consist of the refuse of animal and vegetable
substances, undergoing putrefaction, mixed with calcareous earth;
the refuse of old buildings, particularly plaster; earths from
the vicinity of inhabited buildings; blood, urine, &c. They are
covered, from the rain, by a shed, open at the sides. Cramer, an
author of credit, informs us, that he made a little hut, with windows
to admit the wind. In this, he put a mixture of garden mould, the
rubbish of lime, and putrid animal and vegetable substances. He
frequently moistened them with urine, and in a month or two found his
composition very rich in saltpetre, yielding at least one-eighth part
of its weight. The practice of obtaining nitre from nitre beds, was
followed in France and Germany. It is extracted and refined by the
process already given.
When oxygen gas is presented to azote at the moment of its
liberation, nitric acid is formed. As ammonia is the result of animal
putrefaction, or is formed in the process, hydrogen must unite also
with azote. The azote is furnished by the animal substances. These
facts being known, we are enabled to account for the generation of
nitric acid, and, consequently, of the earthy and other nitrates, in
artificial nitre beds.
In noticing this subject, it is unnecessary to quote the opinion
of Stahl, who believed that there was but one acid in nature, the
sulphuric; and that nitric acid was the sulphuric acid, combined
with phlogiston, which he affirmed was produced by putrefaction; nor
is it necessary to mention the opinion of Lemery, who believed that
nitre exists ready formed in animals and vegetables by the processes
of vegetation and animalization. The experiments of the French
philosophers have put these opinions at rest.
Thouvenal discovered, that nothing more was necessary for the
production of nitre than a basis of lime, heat, and open air; so that
nitre beds, formed of putrefying animal and vegetable substances,
with the conditions thus stated, must produce saltpetre; a fact which
experience abundantly justifies.
The process for the formation of nitre, is called _nitrification_.
Although animal substances, by putrefaction, furnish azote,
and nascent azote unites with facility with the oxygen of the
atmosphere, by which nitric acid is generated--(hence the
spontaneous decomposition of nitre composts)--yet Vauquelin is of
opinion, that the presence of calcareous or alkaline substances
is indispensable, and that the production of carbonate of ammonia
from the animal matter, is another compound, which results from
the same decomposition. Ammonia is produced by the union of azote
and hydrogen, and carbonic acid by that of carbon and oxygen. He
considers then, that the presence of lime, magnesia, potash, &c.
_determines_ the union of the azote with oxygen, and of course, the
formation of nitric acid; and as this acid unites with one or other
of these substances, according to circumstances, we have either
nitrate of lime, or of magnesia, or nitrate of potassa. The idea
that water is decomposed in the change which animal and vegetable
substances undergo, in the process of nitrification, is contrary
to observation; for the presence of air in dry situations, is
indispensable to the process.
If a compost, made up of animal, vegetable, and calcareous
substances, and put in small beds or heaps, and covered with a shed
open at both sides, be frequently turned to admit new surfaces to the
air, and occasionally moistened with urine, &c.--nitric acid will be
generated as the putrefaction goes on. When this process is suffered
to proceed until the decomposition is complete, and the beds then
lixiviated, the quantity of nitre will be considerable. In all cases,
we are to observe, that, as various earthy nitrates are produced,
and mostly nitrate of lime, potash, or wood-ashes which contain this
alkali, are to be used.
It was long since shown by Glauber, that a vault plastered over with
a mixture of lime, wood-ashes, and cows' dung, soon becomes covered
with efflorescent nitre; and that, after some months, the materials
yield, on lixiviation, a considerable proportion of this salt. M. de
Roder, speaking of nitrous walls, observes, that the efflorescence of
nitre on them is in consequence of the stone, lime, and sand employed
in the building.
What is denominated the _saltpetre rot_, is an efflorescence observed
on the walls of old buildings, and on the ground. Dr. C. F. Gren,
professor at Halle, in Saxony, (_Principles of Modern Chemistry_,
vol. ii, p. 128), very justly remarks, that, among the matters
capable of corruption, those are the most convenient in making
nitre, which contain the greatest portion of azote, of which animal
substances are the first; among which he enumerates flesh, blood,
skins, excrements of animals, old woolen stuffs, and urine. He also
mentions marsh plants, green herbs, mud from streets trodden by
cattle, and the ground from marshes or bogs. As a compost he adds,
that the ground from church-yards, where corpses have successively,
and during a long series of years, undergone corruption, would be
the best for artificial nitre beds. On the subject of nitre beds,
the reader may consult the _Recueil de Mémoires et de Pièces sur la
formation et la fabrication du saltpetre, à Paris_, 1786, 4to. These
remarks on the generation of nitre, although of more ancient date,
are confirmed by James and Herman Boerhaave, (_Chemistry, &c._)
Hoffman, (_de Salium Medicorum, et de Præstantissima Nitri Virtute_),
Stahl, (_de Usu Nitri Medico_), Neuman, (_chemical works_), and
Lewis, (_Materia Medica_)--all of whom have written more or less on
the formation of saltpetre; to which we may add the observations of
Parr, (_London Medical Dictionary_, vol. ii, p. 24.)
The process for extracting saltpetre from damaged gunpowder is
nothing more than putting it into a boiler, and adding water
sufficient to cover it. On applying heat, the nitre will be
dissolved. If any scum forms, it must be removed. When the solution
is effected, pour it on a sufficient number of filters, and collect
the fluid which passes through. The residue may be treated with more
water, and the whole again filtered. After boiling the solution, set
it aside to crystallize. The sulphur may be recovered, by subliming
the residue in a temperature not sufficient to inflame it. The
charcoal may be used again for the same purpose.
Saltpetre, when properly refined, does not contain any foreign salts,
and its purity may be known by a variety of experiments, as follows:
make a solution of the salt in distilled water, and filter it through
paper. Put a portion of it in a wine glass, and add a solution of
carbonate of potassa. To another portion, add a small quantity of
muriate, or in preference, nitrate of barytes. To a third portion,
add nitrate of silver. If the fluid in the first glass remains clear,
without any turbidness, we are to infer the non-existence of earthy
salts; if turbid, that it contains lime, or some other earth, either
in the form of a nitrate or muriate. The addition of oxalate of
potassa to another portion of the solution will show the presence
of lime by forming a precipitate, and the addition of carbonate of
ammonia, and then of phosphate of soda, will indicate magnesia. If
the second glass remains transparent, it shows that neither sulphuric
acid, nor any of the sulphates are present. If the fluid in the third
glass continues also clear, we infer that none of the muriates exist.
These experiments are sufficient to show the purity of saltpetre. It
would afford perhaps more satisfaction to institute also the same
experiments on other samples of nitre, by which a comparison may
be formed of the relative purity of each. To make an analysis of
the salt, with the view to determine the proportion of the foreign
substances would be altogether unnecessary for common purposes. A
regularly defined crystal would, in a great measure, point out its
purity. The double refined saltpetre is chemically pure. Artificers
determine the purity of nitre by its flame; if white, they call it
pure, if yellow, impure.
The same reagents may be used in the examination of gunpowder, as
we shall notice hereafter. If a portion of powder be mixed with
distilled water, the water will dissolve only the saline substances,
leaving the charcoal and sulphur. When the whole is thrown on a
filter, the fluid, which passes through, will contain the saltpetre,
and foreign salts, if any are present. The same experiments may
then be performed with the solution, and the quality of the nitre,
of which the gunpowder was made, be determined. Some gunpowder
absorbs a large portion of water, which is owing to the presence of
deliquescent salts. These salts may be detected by proceeding in the
way we have pointed out. The art of refining saltpetre is so well
known of late in the United States, especially by the Messrs. Dupont
of Brandywine, Delaware, that our gunpowder is of a very superior
quality. I have examined various specimens of this saltpetre, and
gunpowder made with it, and could not detect any of the sulphates
or muriates, either alkaline or earthy. For the manufacture of
gunpowder, and fire-works generally, the nitre, it may be observed,
cannot be too pure.
In pyrotechny, it is necessary to have the nitre in powder.
Pulverizing it in a mortar is a tedious method, if a large quantity
is required for use. There is an advantage, likewise, in the mode
we will describe; because the saltpetre, besides being extremely
fine, is made perfectly dry. Put into a copper kettle, whose bottom
must be spherical, fourteen pounds of refined saltpetre, with two
quarts or five pints of water. Put the kettle on a slow fire, and if
any impurities rise and form a scum, remove them; keep constantly
stirring with two large spatulas, till the water evaporates, and
the nitre is reduced to a powder. This will be perfectly white, and
almost impalpable. If it should boil too fast, remove the kettle, and
set it on wet sand, which will also prevent the nitre from adhering
to the pot. It should be kept in a dry place. This process of
powdering saltpetre is performed on a large scale for the manufacture
of gunpowder.
_Sec. II. Of Nitrate of Soda._
This salt has been recommended in lieu of nitre, for preparing
certain fire-works; but we confess, we can see no particular
advantage in using it. It has the property of attracting humidity
from the air, and on that account is rendered unfit for the
manufacture of gunpowder. This salt is composed of nitric acid and
soda. It was formerly called _cubic nitre_. It may be formed, very
readily, by saturating nitric acid with soda, and evaporating the
solution. It crystallizes in rhomboidal prisms. It may be formed more
economically, by mixing together the solutions of nitrate of lime and
sulphate of soda, filtering the mixture, and evaporating the filtered
liquor. It will be sufficient to observe, that it deliquesces, or
absorbs moisture, and in the fire, that its phenomena are the same as
those of nitre. It does not melt so readily.
Used in the same proportion as nitre, it will form a gunpowder, which
soon, however, spoils by exposure. It will, like nitre, communicate
a yellow colour to the flame of alcohol. Experiments were made with
this salt, with the view to the fabrication of gunpowder, by MM.
Bottée and Riffault. Their conclusions, as we have stated, may be
seen in their work on _gunpowder_. Professor Proust says, that five
parts of nitrate of soda, with one of charcoal, and one of sulphur,
will burn three times as long as common powder, so as to form an
economical composition for fire-works.
The _cubic nitre_, and the _nitrum flammans_ were known, and so
called, by the older chemists. The former we have seen, is the
nitrate of soda, and the latter, is a combination of nitric acid and
ammonia. Nitrate of soda, consists of 6.75 acid + 3.95 soda.
Nitrate of ammonia possesses the property of exploding; and, when
exposed to a temperature of about six hundred degrees, is decomposed,
furnishing the nitrous oxide, called also the protoxide of azote, and
exhilarating gas, besides water. Nitrate of ammonia is composed of
6.75 acid + 2.13 ammonia + 1.125 water.
_Sec. III. Of Chlorate of Potassa._
This salt, formerly called hyperoxymuriate of potassa, is used for
sundry preparations, and especially for experimental fire-works. It
is prepared by dissolving one part of carbonate of potassa in six
parts of water, and saturating it with chlorine, formerly called
oxymuriatic acid gas. This operation is usually performed in a
Woulfe's apparatus. The gas, as it proceeds from the retort or gas
bottle, is brought in contact with, and passes through, the fluid.
It is formed by pouring liquid muriatic acid on the black oxide of
manganese, or by pouring sulphuric acid on a mixture of muriate of
soda, and the black oxide. When the saturation is nearly complete,
crystals fall down. These being dissolved in boiling water, and the
solution allowed to stand, pure chlorate of potassa will be formed.
This salt is composed of 9.5, chloric acid, and 6 potassa; and
chloric acid is formed of 28.87, chlorine, and 32.28, oxygen. It
is to the oxygen in the salt, that its particular properties in
fire-works are to be ascribed.
This salt is decomposed by all combustible bodies, and detonations
generally accompany the decomposition. Hence it is used in a variety
of experiments, some of which we will give.
Three parts of the salt and one of sulphur detonate when rubbed in a
mortar. The same mixture, struck with a hammer on an anvil, produces
a loud explosion. Phosphorus detonates with this salt either by
trituration or percussion. The quantity of each should not exceed a
grain. Treated in the same manner with almost all the metals, the
same effect takes place. Cinnabar, antimony, pyrites, &c. produce
the same effect. Nitric acid, poured on a mixture of this salt with
phosphorus, produces flashes of fire. A mixture of the chlorate and
white sugar, when touched with sulphuric acid, immediately inflames.
Hence it is used in the preparation of pocket lights; the mixture
being put on a common sulphur match, and immersed in sulphuric acid.
The same preparation of sugar and chlorate of potassa, put over a
tube used for firing artillery, will set fire to the priming fuse, by
dropping on it sulphuric acid. Owing to this effect, M. Gassicourt
(_Archives des Découvertes_), recommended a similar mixture for
discharging cannon by means of this acid. As it contains a large
quantity of oxygen, that gas may be obtained from it by distillation.
Light decomposes it. It should, therefore, be excluded from the light.
As this salt, when mixed with inflammable substances, detonates when
struck with a hammer, it has been used for the purpose of inflaming
gunpowder without the use of the flint and steel. There are several
formulæ given for the purpose. We remarked, when treating of the
general theory of fire-works, that the Rev. Alexander Forsyth
discovered a new kind of gunpowder, which inflames merely by
percussion; that the gun-lock, which he contrived, was calculated
for firing cannon, as well as musquetry; that it was so contrived
as to hold forty primings of such powder; and that the act of
raising the cock primes the piece. In his composition, each charge
of priming contains no more than one-eighth of a grain of chlorate
of potassa. Since that period, it appears, that the lock, as well
as the powder, has been improved, although neither of them is in
general use. Thenard, (_Traité de Chimie_, tome ii, p. 559, troisième
édition), has given a formula for preparing a priming powder of this
salt, adapted to the new lock, which is made by mixing it with 0.55
of nitrate of potassa, 0.33 of sulphur, 0.17 of the raspings of
peach-wood passed through a fine sieve, and 0.17 of lycopodium, or
puffball. (See _Inflammable Powder_.)
This salt also produces powerful effects with charcoal and sulphur.
Three parts of it, with half a part of sulphur, and half a part
of charcoal powder, produce most violent explosions. Two persons,
in 1788, lost their lives by it. If this mixture be thrown into
concentrated sulphuric acid, a brilliant flame is produced. Such
mixtures, we are informed, will explode spontaneously. It should
not, for that reason, be kept prepared. Chlorate of potassa has
been used in the place of nitre, for the manufacture of gunpowder,
in consequence of its decomposition by charcoal. From its explosive
effects, M. Berthollet was induced to propose it as a substitute
for nitre. The proportions used by Chaptal, (_Chimie Appliqué aux
Arts_, tome iv, p. 198), are six parts of chlorate of potassa, one
of sulphur, and one of charcoal. They are to be mixed in a marble
mortar with a wooden pestle. The first experiment was made at Essone,
in France, in 1788. No sooner, however, had the workmen begun to
triturate the mixture, than it exploded with violence, and killed two
persons.
The force of this gunpowder is greater than that of the common sort;
but the danger of preparing it, and even of using it, is so great,
that these circumstances will always prevent its introduction. A
salt, containing so much oxygen, and so loosely combined, that even
the slightest friction, in contact with inflammable bodies, will
separate it, must, of necessity, prevent its use in that way.
The experiments, which were made at the arsenal at Paris, on the 27th
of April, 1793, comparing the effects of muriated powder, and the
superfine common powder, have given us the following results:
1st. By the eprouvette of Darcy, consisting of a cannon, which, being
suspended to the extremity of a bar of iron, described by its recoil
an arc, of which the degrees can be measured.
_Recoil._
2 drachms muriatic powder, 15 deg. 2/20
2 ---- do do moistened, 14 -- 1/20
2 ---- common powder, 10 -- 7/20
2 drachms common powder, 10 -- 1/20
3 ---- muriatic powder, 20 -- 9/20
3 ---- common powder, 16 -- 6/20
From these results, it appears, that, by the eprouvette of Darcy, the
muriated powder, or that prepared with chlorate of potassa, gave a
superiority of force of about one-fourth.
2nd. By the eprouvette of Regnier, which is repelled by the
explosion, to a distance greater or less, measured by the degrees of
the arc which it describes:
Muriated powder, 42
Idem, 51¾
Idem, moistened, 52
Common powder, superfine, 23
Idem, 22½
From which it results, that by the eprouvette of Regnier, the force
of the powder of the oxymuriate is double that of the nitrate, or
common powder.
M. Ruggieri is of opinion, that chlorate, or hyperoxymuriate of
potassa may be employed with advantage in the composition of rockets,
but we have not heard that it has been used. It is more powerful in
its effects, and probably for this reason he recommended it. This
salt, mixed with other substances, will produce the _green fire_ of
the palm-tree, in imitation of the Russian fire.
Chloric acid may be obtained in a separate state, by boiling the
compound solution formed by passing chlorine gas through a solution
of barytic earth, with phosphate of silver, which separates the
muriatic acid. By evaporation, the chlorate of barytes will
crystallize in fine rhomboidal prisms. When these crystals are
dissolved in water, and diluted sulphuric acid added by degrees,
an acid liquid will be obtained, which, if the sulphuric acid be
added cautiously, will be found entirely free from the latter acid
and barytes, and not affected by nitrate of silver. This is the
chloric acid dissolved in water. Chloric acid unites with sundry
bases. Combined with ammonia, it forms a fulminating salt, formerly
described by M. Chenevix. This salt is formed, by mixing together
carbonate of ammonia, and chlorate of lime. The carbonate of lime
is then separated by the filter, and the clear liquid, holding the
chlorate of ammonia in solution, is evaporated. Chlorate of ammonia
is very soluble in water and alcohol, and decomposed by a moderate
heat.
Chlorates, as the chlorate of potassa, are formed more readily
in the manner already stated: _viz._ by saturating the base with
chlorine, but in this case two salts are produced, the chlorate and
hydrochlorate. Chloric acid has also been obtained in a separate
state, from chlorate of potassa, by a process recommended by Mr.
Wheeler.
Perchloric acid, composed of seven primes of oxygen and one of
chlorine, is obtained from chlorate of potassa, treated in a
particular manner. Three parts of sulphuric acid and one of chlorate
of potassa, when heated, will give a saline mass, consisting of
bisulphate of potassa, and perchlorate of potassa. Deutoxide of
chlorine will be evolved. The perchlorate detonates feebly when
triturated with sulphur.
_Sec. IV. Sulphur._
Sulphur, or brimstone, is a principal ingredient in almost all the
compositions of fire-works. It should, therefore, be pure. The
flowers may be considered the purest kind of sulphur.
Sulphur is found native, either alone, or accompanying certain
minerals, such as gypsum, rock-salt, marl, and clay, as in
Switzerland, Poland, and Sicily. In the neighbourhood of
salt-springs, it is also found; and frequently in water, in
combination with hydrogen, forming the natural hepatic waters. It
is also found on the surface of the earth, as in Siberia. Volcanic
sulphur, or that which occurs in the fissures and cavities of lava,
near the craters of volcanoes, is very common.
Solfatere, Sicily, the Roman states, Guadaloupe, and Quito, in the
Cordilleras, are most celebrated for native sulphur. It has been
found in the United States, but in no quantity. We have a number
of mineral springs, which deposite sulphur. The Clifton Springs of
Ontario are of this kind. It occurs abundantly, in combination with
hydrogen, as sulphuretted hydrogen gas, in various parts of the
United States.
Native sulphur is abundant in the island of Java. It is obtained
from the now almost extinct volcano, about sixty miles from the
town of Batavia. At the bottom of the crater, there is said to lie
many hundred tons of native sulphur. Silliman (_Journal_, vol. i,
p. 58) observes, that it is in the crater of this volcano, that the
celebrated lake of sulphuric acid exists, "and from which it flows
down the mountain, and through the country below, a river of the same
acid."
Sulphur, however, is usually obtained from pyrites or metallic
sulphurets, by fusion and sublimation. It is usually denominated by
the name of the place whence it comes. Hence we have the Italian and
Sicilian sulphur; the crude, roche, or stone brimstone of Marseilles,
&c.
The quantity of sulphur, which may be obtained from the galena, or
sulphuret of lead, by sublimation, is considerable. Twenty-five per
cent is the loss sustained in the reduction of the lead ore, which
occurs so abundantly in the neighbourhood of St. Louis. When general,
the then lieut. Pike, (_Expeditions, &c. Appendix_) interrogated
Mr. Dubuque in 1805, respecting the quantity of lead obtained from
those mines, a detailed account of which is given by Schoolcraft,
he replied that the mineral would yield seventy-five per cent. of
lead, and hence the twenty-five per cent. loss must be the sulphur,
together with any foreign matter it may contain.
The experiments of M. Vauquelin, (_Annales de Chimie_, 1811) to
determine the quantity of sulphur contained in some metallic
sulphurets, show, at once, the proportion which may be obtained from
those combinations. Thus he found, that sulphuret of copper contains
21.31 per cent of sulphur; sulphuret of tin, 14.1; sulphuret of lead,
13.77; sulphuret of silver, 12.73; sulphuret of iron, 22; sulphuret
of antimony, 25; sulphuret of bismuth, 31.75; sulphuret of manganese,
74.5; and sulphuret of arsenic, 43.
Of native or prismatic sulphur, there are two species, the common and
volcanic. The former is of two kinds, the compact and earthy.
Sulphur, says Hanway, (_Travels, &c._) is dug at Baku on the western
side of the Caspian sea. It is found in the neighbourhood of the
celebrated naphtha springs, some of which form a mouth of 8 or 10
feet diameter.
Von Humboldt (_Annales de Museum National_) communicated to the
French national institute, that he discovered, in the province of
Quito, a bed composed of sulphur and quartz, in a mountain of mica
slate, and also sulphur in primitive porphyry. Kirwan (_Geological
Essays_, p. 143) observes, that sulphur promotes decomposition, by
absorbing oxygen, while it is thus converted into vitriolic acid; but
moisture is also requisite. He attributes, in the same manner, the
decomposition of stones that contain pyrites.
As the sulphur, which occurs in commerce, is chiefly obtained from
its native combinations, it may be proper to make some brief remarks
on this head. Sulphur in the state of combination is abundantly met
with, and in all countries. It is found in the state of sulphuric
acid, in various salts, as gypsum, epsom salt, native alum, &c.; and
united with metals, forming natural sulphurets, as in sulphuret
of iron, or iron pyrites, sulphuret of copper, or copper pyrites,
sulphuret of lead, or potter's lead ore, called also galena,
sulphuret of antimony, or crude antimony, sulphuret of zinc, or
blende, sulphuret of mercury, or cinnabar, sulphuret of arsenic, or
orpiment, &c. In fact, it appears to be a general mineralizer. It is
found also in some plants, and in animal substances.
Without detailing minutely the processes employed for extracting
sulphur from its combinations, which may be seen in Thenard, (_Traité
de Chimie_, tome i, p. 184) it will be sufficient to observe, that,
in general, pyrites, both of iron and copper, are arranged in
alternate layers in the form of a pyramid, and the _roasting_ is
continued for several months. Part of the sulphur is consumed, and
part is sublimed, and is condensed and collected in hollows, in the
upper part of the pyramid, whence it is removed several times a day.
It is also obtained from pyrites, by a kind of distillation. They
are reduced to coarse powder, and put into hollow iron cylinders, or
retorts, where the sulphur is disengaged and melted, and thence runs
into vessels of water. This process is employed in Saxony, where nine
hundred pounds of pyrites will yield one hundred to one hundred and
fifty pounds of sulphur, which is afterwards purified.
When melted and cast into wooden moulds, it forms the roll brimstone;
and, by sublimation, conducted in large chambers, as we shall
afterwards mention, it is converted into the flowers of sulphur. The
residue of the sublimation is _sulphur vivum_, which is also used in
fire-works. The roll brimstone is frequently adulterated.
In the island of Anglesea, it is obtained by the sublimation of the
yellow copper ore. The operation is conducted in kilns, and the
sulphur is conveyed by means of long horizontal flues, and collected
in large chambers. As the United States furnish an abundance of
martial pyrites, and also galena, sulphur might be manufactured in
this country, and advantageously, especially from galena, which is
very abundant in the neighbourhood of St. Louis. In the roasting
of the ore, all the sulphur is now lost, tons of which might be
collected.
For the purpose of gunpowder, the purer the sulphur, the better will
be the powder; hence attention is always paid to this circumstance.
M. Michel, one of the principal refiners of sulphur at Marseilles,
has improved the process for purifying sulphur for the purpose of
gunpowder. M. Libaw, connected likewise with the French national
powder establishment, has furnished a very useful and important
memoir on the same subject.
Two methods are proposed for the refining of sulphur, which we
will briefly state, namely, fusion, and sublimation. The first is
conducted in iron pots fixed in a furnace; and the sulphur, before
it is thrown in, is beaten into small pieces with a mallet. This
facilitates the fusion, and renders it more uniform. Small portions
at a time are thrown into the boiler, and stirred frequently with
a wooden spatula. This manipulation ought to be continued till the
boiler is filled. The heat must be regulated so as not to inflame, or
sublime the sulphur.
The sulphur of commerce is commonly of three different colours, viz:
citron-yellow, deep yellow, and brownish-yellow. These colours depend
on the different degrees of heat to which the sulphur was exposed,
in its extraction. The operation of refining consists in conducting
the fire in such a manner, as that the colour of the sulphur will
assume a brilliant yellow, bordering on a green. We must, therefore,
to produce this effect, operate on the sulphur according to its
colour. For the green sulphur, as little heat has been used for its
extraction, the fire may be left under the boiler until there is no
more left to melt than the top. The sulphur of the yellow colour may
be kept longer on the fire, which may be removed when the mass is
melted three-fourths. The sulphur of a brown colour, being already
much burnt, may be removed when the mass is melted one-half. If it
is required to operate on all the varieties at the same time, in
order to produce sulphur of a uniform colour, in that case we must
fill the boiler one-half with the green sulphur, one-fourth with the
yellow, and the remainder with the brown, and removing the fire when
the yellow is almost wholly melted. The boiler is then covered with
a lid. The fusion is completed by the heat of the mass. The light
bodies then raise themselves to the surface, forming a black scum,
which is removed, and the heavy bodies fall to the bottom. The boiler
remains for four or five hours, uncovering it from time to time to
take off the scum. The fluid part is removed, and is suffered to
congeal, taking care not to disturb the deposite.
The second process of refining is by sublimation. This operation
consists in subliming it in a close apparatus, which in sulphur
refineries are boilers placed in brick work, and furnished with
heads. These heads communicate by a pipe with a vaulted chamber,
placed at some distance from the furnace. The chamber serves to
collect the sulphur. There is usually a stone slab fixed between
the chamber and the head. The chamber is furnished with one or two
iron-plate valves. There is an opening in the head of each boiler,
in order to renew the sulphur: it is closed very tight by a plate of
iron. There is an opening also in the chamber, to admit a person,
which is closed likewise by an iron plate. The heads are luted before
the process is commenced.
By this process the sulphur is refined; for the pure part is
sublimed, and the foreign substances remain in the pots. The product
thus obtained is the ordinary flowers of sulphur. If the heat be
moderate, the sublimation is more perfect. It is necessary at
the same time that the temperature of the chamber should be low,
otherwise the sulphur will melt, which frequently takes place. Coarse
particles are separated from the flour, should they occur, by a sieve.
During the first part of the process, there is formed some sulphurous
acid gas, which is not produced after the vapour of sulphur forms the
atmosphere in the head. This is known to exist, by the acid taste of
the sulphur, and its black colour.
Detonation very frequently takes place, and sulphurous acid gas is
produced. In the sublimation of brimstone, about ten to eleven per
cent. is the usual total loss, of which six or seven per cent. is
residue. The acid may be separated from the sulphur by washing it in
water, and afterwards drying it. It is then called the washed flowers
of sulphur. (See _Traité de l'Art de Fabriquer la Poudre à Canon_, p.
153.) by MM. Bottée and Riffault, for a minute description of this
process.
Sulphur undergoes no change by exposure to the air. It is insoluble
in water. It breaks in the hand with a crackling noise. At 170
degrees it begins to evaporate, and when collected it is called
sublimed, or flowers of sulphur. It melts at 218 degrees. When
melted and poured into water, it forms the _sulphurs_ for taking
the impression of coin, &c. If melted, and cooled slowly, it will
crystallize in the form of needles. It is soluble in different
degrees in alcohol, ether, and oils. When sulphur is burnt very
slowly in the open air, it unites with oxygen and forms sulphurous
acid. This acid is used in bleaching. When mixed with nitre, and
burnt in leaden chambers, it forms sulphuric acid, or oil of vitriol,
by which process it combines with a larger quantity of oxygen. There
is another compound called hyposulphurous acid, all the salts of
which are inflammable and burn with a blue flame. Sulphur unites
with the alkalies, earths, and metals. If the alkaline sulphurets be
dissolved in water, and an acid added, the sulphur will precipitate
of a white colour, known by the name of milk of sulphur. It is
considered by some a hydrate of sulphur. The same preparation is
made by subliming sulphur in a vessel containing the vapour of
water. Sulphur unites with chlorine and iodine, forming chlorides,
and iodides. With hydrogen, it forms the sulphuretted hydrogen, or
hepatic gas, called also the hydrothionic and hydrosulphuric acid;
with carbon, the sulphuret of carbon; and with nitre and charcoal, in
the state of mixture, it constitutes gunpowder.
The motionless _ignes fatui_ of Italy, which are seen nightly on
the same spot, are attributed to the slow combustion of sulphur,
emitted through clefts and apertures in the soil of that volcanic
country; but the _Will-with-the-Wisp_, which moves in undulations,
near the surface of the ground, in swampy situations, and where the
putrefactive process is going on, originates in all probability
from decaying vegetable and other matters, and the extrication of
phosphorus. It is known that the acid of phosphorus is found in
plants, and especially those that grow in marshy places, in turf, and
several species of the white woods.
_Mealing of Brimstone._ What is termed the mealing of sulphur by
fire-workers, is no other than reducing it, if it be the roll, to
powder. Large mortars and pestles made of ebony, and other hard wood,
and horizontal mills with brass wheels are used. The _mealing table_
is used by artificers. It is generally made of elm, with a rim around
its edge four or five inches high. One end is narrow, and furnished
with a slider that runs in a groove, and forms part of the rim.
After using as much of the powdered brimstone as is required, copper
shovels being employed, the rest may be swept out at the slider. This
table is also used for the mealing of gunpowder and saltpetre. The
muller is generally made of ebony. After reducing it to powder, it is
then passed through a lawn sieve, furnished with a cover.
As brimstone is frequently adulterated with different substances,
it may be of importance to discover the fraud. We may remark, that,
if it is pure, it will be taken up entirely by chlorine gas, or by
using a solution of caustic potassa. The latter, however, cannot
be depended on in all cases. But the best mode, is that of melting
some of it in a ladle; if any residue remains, after the fumes have
ceased, the presence of foreign substances may be inferred, for
pure sulphur will sublime without leaving any residue. It is not
unfrequently adulterated with common flour. There is another mode of
determining the quality of sulphur, It should, if pure, be completely
soluble in boiling oil of turpentine. If any residue remain, we may
infer the presence of foreign substances, either vegetable, earthy,
or metallic.
It is obvious, that if the brimstone is impure, the effect of it in
fire-works will be imperfect. Flowers of sulphur, however, may be
almost always depended on. In all artificial fire, in which sulphur
forms a part, the _flame_ is more clear, as the sulphur is pure.
Several modes are recommended for the separation of sulphur from
charcoal, in gunpowder, which may be seen by referring to the
analysis, or chemical examination of gunpowder.
Sulphur constitutes one of the ingredients, generally speaking, of
incendiary compositions, used for military purposes, and, in such
cases, is usually mixed with pitch, tar, saltpetre, and sometimes
gunpowder. It is said to be one of the substances, which entered into
the composition of the ancient and celebrated Greek fire; but the
principal character of which, that of burning in water, was owing to
the presence of camphor. This substance, associated with sulphur,
pitch, and nitre, forms one of the most effective incendiaries of all
military fire-works. For such purposes, it is hardly necessary to
add, that the common roll brimstone is sufficiently pure.
As to the mode of preparing these works, the custom is to melt the
resinous substances first, then to add the sulphur, and finally the
saltpetre; and after the whole are melted and thoroughly mixed, to
remove the pot from the fire, and add gradually the gunpowder. If a
carcass is to be made, tow or hemp, or untwisted rope, is immersed in
the composition while hot, and taken out and formed into a ball of
the size required. Rope, treated in the same manner, with the same
composition, will make a more active tourteaux than the common kind.
(See _Carcass and Tourteaux_.)
All oils, whether expressed or essential, can dissolve sulphur.
To make this solution, the oil must be poured on the sulphur,
and sufficient heat applied to melt the substance. While the oil
dissolves the sulphur, it acquires a reddish or brown colour, an
acrid, disagreeable taste, and a strong fetid smell, somewhat
hepatic, resembling that of oil with sulphuric acid.
_Sec. V. Of Phosphorus._
We mention this substance, because it is used in some experiments,
although not in extensive fire-works. It is a very inflammable
substance, inflaming either by friction, or an increase of
temperature. It produces a most brilliant fire, and when mixed with
some substances, exhibits very pleasing phenomena. It usually comes
to us in sticks, which must be constantly kept in water to prevent
its inflammation. Phosphoric matches, phosphoric fire-bottles, &c.
are made of it. These are made in various ways. Phosphorus and
sulphur melted together in a small phial, forms the fire-bottle, or
some add a portion of lime. A sulphur-match dipped in this mixture
and gently rubbed, immediately inflames. They do not last any time,
in consequence of the acidification of the phosphorus. Phosphoric
tapers are usually made with a glass tube, on the breaking of which,
it inflames. When rubbed upon a wall in a dark room, it appears
very luminous. Dissolved in ether, and poured upon boiling water in
the dark, the vapour as it ascends appears remarkably luminous, and
has a pleasing effect. Dissolved in oil, as olive-oil, it forms the
phosphorized oil, which may be rubbed on the face and hands without
injury. This oil has the same appearance in the dark. The time of
night may be known by the light it produces. When mixed with nitrate
of silver, sulphuret of antimony, sulphur, chlorate of potassa, &c.
and struck with a hammer, it produces an explosion more or less loud.
A variety of explosive compounds may be made with it, but they must
be used with great care.
When combined with hydrogen, it inflames spontaneously when brought
in contact with atmospheric air. It inflames also in chlorine
gas. It is supposed to be the cause of the _ignes fatui_, or
_Will-with-the-Wisp_. The formation of phosphoretted hydrogen gas
may be shown in a variety of ways, as the following: throw some
pieces of phosphuret of lime into water, and bubbles of gas will
rise, which will take fire on coming to the air; or, put into a flask
some phosphorus, iron or zinc filings, water, and sulphuric acid,
and the gas will be generated; or, introduce into a small retort,
a solution of potassa, and a piece or two of phosphorus, and apply
heat, immersing the beak of the retort in a basin of water, the gas
will pass over, and inflame as it comes to the surface of the water.
In all these experiments, the water is decomposed; its oxygen goes to
a part of the phosphorus in the first experiment, and the hydrogen
of the water then unites with another portion of phosphorus, which
is then evolved; in the second experiment, the oxygen oxidizes the
metal, and the hydrogen dissolves a part of the phosphorus; and
in the third experiment, the phosphorus unites with the potassa,
forming a phosphuret, which decomposes the water, the hydrogen of
which passes off in combination with some of the phosphorus, forming
the phosphuretted hydrogen gas.
The cause of the spontaneous combustion is, that the oxygen of the
atmosphere unites with the hydrogen and the phosphorus, and forms
water and phosphoric acid; the latter producing a beautiful corona as
it rises in the air. The heat and light given out proceeds as well
from the oxygen gas, as from the phosphuretted hydrogen gas. When
saturated with oxygen, it is no longer inflammable.
There are some other experiments which can be made with this singular
substance.
It was formerly obtained from urine, as that fluid contains some
phosphoric salts. It is now prepared from bones. These are burnt to
an ash, and diluted sulphuric acid is poured on it; the phosphoric
acid it contains is then disengaged, and remains in the fluid. The
sulphate of lime is then separated, the fluid boiled to dryness, and
the dry mass is mixed with charcoal, and distilled in the open fire.
The phosphoric pencil, for writing on a wall, paper, &c. to be
luminous in the dark, is nothing more than a bit of phosphorus put
into a quill. It must be kept in water, and when used, frequently
dipped in water, to prevent its taking fire.
The _phosphoric_ stone of M. Bucholz, described in the _Archives
des Découvertes_, ii, p. 109, is a phosphuret of magnesia, prepared
by melting thirty grains of phosphorus in a small flask, and
adding twenty or thirty grains of calcined magnesia. Although this
process is given by Bucholz, yet, as it is difficult to prevent the
inflammation of the phosphorus, the best mode would be to bring the
vapour of phosphorus in contact with magnesia, in the same manner as
in preparing phosphuret of lime.
The pyrophorus of Wurzer is nothing than a phosphuret of lime. It is
prepared by taking two parts of pulverized quicklime, and one part
of phosphorus; introducing them into a bottle, and covering it with
three parts of quicklime, leaving one-third of the bottle empty; then
putting the bottle into a crucible surrounded with sand, previously
stopping the mouth with clay, and applying heat. Remove the phial
when the phosphorus appears to sublime of a red colour. When the
bottle is opened it becomes luminous, and brought out it inflames.
Phosphorus in the state of acidification, and united with lime, is
found in abundance. Whole mountains in the province of Estremadura
in Spain, are said to be composed of this combination. According
to Mr. Bowles, this stone is whitish and tasteless, and affords a
blue flame without smell when thrown upon burning coals. Mr. Proust
observes, that it is a dense stone, not hard enough to strike fire
with steel, and is found in strata, which always lie horizontally
upon quartz, and which are intersected with veins of quartz. He
adds, that it does not decrepitate on burning coals, but burns with
a beautiful green light. This stone is the common phosphorite. It
contains, according to Klaproth, 32.25 per cent. of phosphoric acid.
Several substances are known under the name of phosphorus, although
they do not contain it, such as Baldwin's phosphorus, or ignited
muriate of lime, Canton's phosphorus, or oyster-shells calcined with
lime, and Bologna phosphorus, or calcined sulphate of barytes.
_Sec. VI. Of Charcoal._
Charcoal performs an important part in all the various kinds of
fire-works. The facility with which it decomposes nitric acid, when
it is combined with salifiable bases, as with potassa in saltpetre,
and its action in all cases wherein nitre is concerned, are
sufficient examples of its effect.
Pure carbon is the diamond. It affords by combustion in oxygen gas,
the same gas as common charcoal, when charcoal is burnt in oxygen, or
in atmospheric air. This gas is carbonic acid, or fixed air. Charcoal
has been considered a long time an oxide of carbon, and according to
some, as Berthollet, a compound of carbon, hydrogen, and oxygen.
Charcoal is insoluble in water. It is not affected by the most
violent heat, if confined in close vessels. It is an excellent
conductor of electricity, but a bad conductor of heat. It is very
indestructible; and, therefore, when wood is charred, it will remain
a long time under ground without rotting. As an antiseptic, it is
powerful. It will therefore prevent the putrefaction of bodies,
and even recover tainted meat. As a preservative of water, for
sea-voyages, it has been long known. The charring of water casks is
designed for the same purpose. The quality of wine is said to be
improved by having the casks previously charred. It possesses the
property of absorbing gases, and to this property is ascribed its
use as an antiseptic, and its disinfecting quality. To the distiller
it is useful, as it destroys effectually the burnt or empyreumatic
smell of liquor. When heated to eight hundred degrees in the open
air, it burns. In oxygen gas the combustion is brilliant, forming in
both instances carbonic acid gas, called also aerial acid, fixed air,
mephitic air, and calcareous acid. This acid is formed in a variety
of processes, and is carbon saturated with oxygen.
Carbon exists in various states of combination, and many of the
compounds into which it enters are inflammable; hence carbonic
acid is generated in the combustion of coal, oils, fat, &c. In the
form of an acid, it is abundant in various stones, such as the
calcareous carbonates, as chalk, marble, limestone, and calcareous
spar, barolite, &c. all which effervesce with acids, the carbonic
acid being liberated. When limestone is burnt, to obtain quicklime,
the carbonic acid is disengaged, for the presence of this acid
distinguishes limestone from pure lime. Carbonic acid is generated
in various processes of nature as well as art. Hence it is produced
in the respiration of animals, and is found in a gaseous state in
wells, cellars, caverns, &c. It neither supports animal life, nor
combustion. In mines it is called choke damp; and the Grotto del
Cani, in the kingdom of Naples, has been long celebrated, on account
of it. This cave is in the side of a mountain, near the lake Agnano,
measuring not more than eighteen feet from its entrance to the inner
extremity; where if a dog or other animal that holds down its head be
thrust, it is killed by the gas. Some experiments were made in this
cave with gunpowder, which see. Carbonic acid, during the formation
of alcohol, in the vinous fermentation, is generated, and its
production appears to be designed by nature to carry off the excess
of carbon, which gives rise to that phenomenon called fermentation.
When combined with water, it forms aerated water, and with alkalies
and water, the aerated alkaline waters. Its union with bases forms
salts called carbonates. Plants have the property of decomposing it,
and in this respect nature has employed a mean of regenerating the
atmosphere, on the purity of which depends, in an eminent degree, the
very existence of animal life. The prime equivalent of carbonic acid
is 2.75, and carbonic acid is composed of carbon 0.75 + 2.0 oxygen.
Carbonic acid may be decomposed when combined with a base, as lime,
by phosphorus and heat, for charcoal and a phosphate of lime will be
produced. But carbonic acid in the state of gas may be decomposed by
potassium. Five grains of potassium will decompose three cubic inches
of gas, and be converted into potassa, producing at the same time
three-eighths of a grain of charcoal. If passed over a coil of fine
iron wire heated to redness, in a porcelain tube, and the operation
repeated, the iron will be oxidized, and the carbonic acid changed
into carbonic oxide gas.
Charcoal will not burn in dry chlorine. It unites with a less
proportion of oxygen, and forms carbonic oxide gas, which burns
with a deep blue flame. This combination is formed by distilling
in a red heat, a mixture of equal parts of iron filings and chalk.
This gas mixed with chlorine gas, and exposed to the sun's rays,
will unite with it, and form chlorocarbonic acid gas. Carbon unites
with azote, and forms cyanogen, the base of Prussic acid. It unites
likewise with hydrogen in two proportions, forming the hydroguret and
the bihydroguret of carbon, both of which are carburetted hydrogen
gases. The former is obtained by distilling a mixture of four parts
of sulphuric acid, and one of alcohol. The gas is very inflammable,
and burns with great splendour; and on that account may be used for
exhibition, in an apparatus similar to that of Cartwright. (See
_Fire-works with Inflammable air_.) It was called by the
German chemists olefiant gas. The other species, called also the
light carburetted hydrogen gas, may be obtained by agitating the mud
at the bottom of stagnant pools; and by the distillation of moist
charcoal, wood, pitcoal, pitch, or almost any animal or vegetable
substance. The gas, used for _gas-lights_, is the same. It is
usually obtained from pit coal. We may merely observe, that the gas
used for that purpose, _i. e._ for illuminating streets, theatres,
manufactures, &c. as obtained in the common method, is not altogether
the bihydroguret of carbon; but, according to the experiments of Dr.
Henry, a mixture of that gas with the hydroguret, and occasionally
carbonic oxide.
Carbon enters into other combinations. It exists as a component part
of gums, resins, sugar-starch, and other vegetable products, as the
vegetable acids, its union with iron forms steel, a substance greatly
used in the preparation of some fire-works, especially in some of the
_rains_ and _stars_, and in the composition of _brilliant fire_. (See
_Iron_.)
As charcoal enters into the composition of gunpowder, and the
effective force of powder depends considerably on the quality, as
well as the proportion of charcoal, it is obvious for this purpose,
it should be as pure as possible.
Carbon is always obtained from some of its combinations, as from
pitch, tar, rosin, wood, and oil. Various processes are employed for
this purpose. Thus, by the combustion of rosin and oil, as well as
pitch, tar, turpentine, &c. a soot is formed that collects, called
lampblack, which is nothing more than the carbon or charcoal. When
pit-coal is _charred_ in an oven, called a coke oven, all the bitumen
and sulphur contained in it are disengaged, and a charcoal remains,
called, however, _coke_. Wood, when charred is decomposed; all the
volatile parts are disengaged with carburetted hydrogen gas, and the
woody fibre is converted into coal. This coal is more or less dense
according to the compactness of the wood. Hard woods furnish the most
solid coal, and light woods on the contrary.
When the solid parts of animals, as bone, are charred, the volatile
products, principally ammonia or volatile alkali, are dissipated,
and there remains a substance called bone-black, improperly called,
_ivory black_.
The carbonization of wood in the common way is well known: after
it is cut to the lengths required, it is piled on the ground in a
pyramidal form, and covered with sod and clay, leaving a place for
the current of air, and the smoke. The wood is then set on fire, and
when the whole is burnt to a coal the vents, &c. are closed with sod
and clay.
Nicholson (_Chemical Dictionary_) observes, that in the forest of
Benon, near Rochelle, great attention is paid to the manufacture, so
that the charcoal made there fetches twenty-five or thirty per cent.
more than any other. The wood is that of the black oak. It is taken
from ten to fifteen years old, the trunk as well as the branches, cut
into billets about four feet long, and not split. The largest pieces,
however, seldom exceed six or seven inches in diameter. The end that
rests on the ground is cut a little sloping, so as to touch it merely
with an edge, and they are piled nearly upright, but never in more
than one story. The wood is covered all over about four inches thick
with dry grass or fern, before it is enclosed in the usual manner
with clay; and when the wood is charred, half a barrel of water is
thrown over the pile, and earth to the thickness of five or six
inches is thrown on, after which it is left four-and-twenty hours to
cool. The wood is always used in the year in which it is cut.
Turf or peat has been charred lately in France, it is said, by a
peculiar process, and, according to the account given in Sonnini's
Journal, is superior to wood for this purpose. Charcoal of turf
kindles slower than that of wood, but emits more flame, and burns
longer. It boiled a given quantity of water four times, while an
equal weight of wood charcoal boiled the same quantity but once. In a
goldsmith's furnace, it fused eleven ounces of gold in eight minutes,
while wood charcoal required sixteen. The malleability of the gold,
too, was preserved in the former instance, but not in the latter.
Iron heated red-hot by it, in a forge, was rendered more malleable.
In charring wood it has been conjectured, that a portion of it is
sometimes converted into a pyrophorus, and that the explosions that
happen in powder-mills are sometimes owing to this.
Bartholdi supposes, that such explosions are owing to the formation
of phosphoretted hydrogen gas, while others attribute them to the
absorption of oxygen, by the hydrogen contained in the coal, and the
consequent evolution of free caloric. Percussion, which necessarily
takes place in mixing the materials of gunpowder by stampers, no
doubt accelerates the combustion. The addition of water, and having
the charcoal previously pulverized, will prevent such accidents. (See
_Gunpowder_.)
Coal prepared in the manner above stated, is liable to many foreign
admixtures, nor can the process be so well regulated as to produce
coal of a uniform quality throughout. The present improved process
has many advantages, as experience has proved. It consists in
charring the wood in confined vessels, made of iron. These are
usually cylindrical, furnished with an iron cover, and placed in
furnaces. The pyroacetic, formerly called the pyroligneous, acid,
which is formed in the destructive distillation of wood, is caught
for use. This acid is useful to the calico printer, dyer, &c. in
making their iron liquor, and when purified, is employed in Europe in
the place of vinegar, as it is more pungent, and highly concentrated.
When pine and various kinds of wood, which yield turpentine, are
carbonized, we obtain tar during the process.
Chaptal informs us, that tar is obtained from the wood of the trunk,
branches, and roots of the pine, which are heaped together, covered
with turf, and set on fire to produce a close combustion, in the same
manner as for making charcoal. The oily parts which are disengaged,
trickle down, and are received in a gutter, which serves to convey
them to a tub. The most fluid part is sold under the name of huile de
cade; and the thicker part is the tar used for paying or painting the
parts of shipping and other vessels.
According to the wood submitted to the process of charring, the
products are, more or less, various; but in all cases it is only
the solid part, or ligneous fibre, that furnishes the coal. By the
ordinary process we obtain sundry volatile products, among which are
pyroacetic acid and carburetted hydrogen gas.
When wood is carbonized in the usual manner, it yields from 16 to 17
parts of charcoal in the hundred; but when the operation is conducted
in close vessels, the product is 28 per cent. a saving of eleven or
twelve per cent. By this difference in the quantity, it appears that
eleven or twelve per cent. is burnt in the common process.
M. Mollerat was the first who tried the experiment with iron
cylinders.
M. Vauquelin (_Annales de Chimie_, tome lxvi, p. 174) has given
some observations on the carbonization of wood in close vessels,
predicated on a Memoir of M. Mollerat; both of which are interesting.
The apparatus used by M. Mollerat is described by Thenard, (_Traité
de Chimie_, iii, p. 373,) to be composed of two parts, viz: a furnace
with a moveable dome, and a cylindrical kettle, or vessel of iron
sufficiently large to contain a cord of wood. It is furnished with a
cover and pipe. The pyroacetic acid is collected. Smaller cylinders
are preferred, because the wood is ignited more readily and the
charcoal is more of a uniform quality.
From 100 parts of the following named woods, Messrs. Allen and Pepys
(_Phil. Trans._ 1807) obtained the following proportional parts of
charcoal:
Beech 15.00
Mahogany 15.75
Lignum Vitæ 17.25
Oak 17.40
Fir 18.17
Box 20.25
See also the experiments of Mr. Mushet, in the third volume of
Tilloch's _Magazine_.
It appears by the _Annales de Chimie_, vol. 66, and the _Retrospect
of Discoveries_, vol. vi, p. 100, that three brothers have
established at Pellerey, near Nuits, Cote d'Or, a manufactory on a
large scale, for making charcoal in close vessels.
The quantity of charcoal they obtained is double that by the usual
mode, while it requires only one-eighth part of wood to be consumed
in the distillation; it is also better than the common, as a given
quantity evaporates one-tenth more water than the other; hence
iron masters may obtain twice as much iron from the use of a given
quantity of wood; and in addition to this, there is also prepared a
number of other articles, of each of which in order.
350 kilogrammes (700 lbs.) of wood, yield 25 or 30 of tar, which
retains so much acid that it is soluble in water; but when it is
washed, and rendered thick by boiling, for some time, it offers more
resistance to water. If mixed with one-fifth of rosin it is rendered
equally fit for the use of ships, &c. as the common tar.
Four sorts of vinegar are prepared, all of which are perfectly
limpid, which do not, like the common, contain any tartar, malic
acid, resinous or extractive matter, nor indeed any mineral acid,
lime, copper, or other substances. The simple vinegar marks--2°
hydrometer for salts, at 12° centigrade thermo. it is stronger tasted
than common vinegar, and produces a disagreeable irritation. The
aromatic vinegar is prepared with tarragon, the smell is agreeable,
but it has the same fault as the former. The vinous vinegar is formed
by adding some alcohol to simple vinegar; it has a very sensible
odour of acetic ether; the alcohol softens the flavour in some
degree, but the vinegar is still very sharp. The acid, called strong
vinegar, is in fact a very good acetic acid at 10-1/2° hydr., it is
very white, clear, and sharp, without the usual burnt flavour, and
seems to form the basis of the preceding kinds. It can be sold for
8 or 9 francs (7s.) per lb. which is only half the price of that
distilled from verdigris. Although not so agreeable to the taste as
common vinegar, these new kinds are more elegant to the eye, and do
not mother.
The editor of the Retrospect makes the following observations:
The proprietors of this manufactory seem to be perfectly aware of all
the several productions which could be prepared from the refuse of
their principal object; and we have no doubt but that the substances
they procure in this manner will amply compensate them for the use of
the capital that must be invested in building the furnaces.
The nature of the vessels in which they distil the wood is not
mentioned, but they are probably cast iron retorts, or vessels of a
similar nature, in which a distillation _per latus_ takes place. The
application, therefore, of lord Dundonald's furnaces for procuring
coke to this purpose would be still more advantageous.
A cubic yard of wood yields 100 quarts of acid liquor, besides 50 or
60 lbs. of thick oil.
The method of making charcoal of a _uniform quality_, for which a Mr.
Kurtz has taken out a patent, is the following:
A sheet-iron chest, which has a cover that fits it tight, and a pipe,
or tube, that descends nearly to the bottom, and coming out from its
side above, is fixed in brick work. In this the billets of wood are
put. Fire is then made underneath. It is obvious, that the wood is
kept at one temperature from its being immersed in vapour, as the
vapour cannot escape at the top, but must descend to the bottom,
and then proceed up the pipe, by which it is conveyed away. The
effect is, that the charring process goes on regularly, and the wood
is charred equally. The carbonization is finished when the vapour
ceases to appear, and nothing but carburetted hydrogen gas escapes.
The charring of bones is performed in iron cylinders, furnished with
tubes to receive, and convey away, the impure ammonia.
In the manufacture of powder, particular kinds of wood are selected
for carbonization. These are generally, willow, hazle, maple, poplar,
linden, buckthorn, or alder, or those which are tender and light,
because, as they are less dense, and consequently more friable,
they enflame and consume more rapidly: they are known in the arts
by the name of _white wood_. When a less sudden effect is to be
produced with the gunpowder, and the combustion prolonged, as in some
sky-rockets, the charcoal of hard wood is to be preferred, such as
the oak, beech, &c. When the wood is gathered, the bark is removed,
and the wood exposed to the sun to dry: it is then cut into billets,
and charred. The ashes, if any be formed, are to be carefully
separated.
In considering the use of charcoal, therefore, for the preparation
of gunpowder, we are to direct our inquiries to the choice of wood
for carbonization, and the best process for carbonizing it. All light
woods, we remarked, as the linden, willow, poplar, &c. furnish the
lightest coal, and on that account are preferred. It is remarked,
that tender wood, besides making a light, friable, and porous coal,
is more combustible than ordinary hard, and more compact wood, and
the coal that it furnishes leaves less residue after combustion.
Many experiments have been made with coal prepared from different
kinds of wood, with a view of ascertaining the kind best adapted
for the manufacture of gunpowder. M. Letort, at the powder mills
of Essonne, in France, instituted a number of experiments of this
kind. He made gunpowder with the coal of several kinds of wood, and
compared its effects by a mortar eprouvette. The result was, that
the powder made with the coal of poplar, was the strongest; and the
other powder, made with the coal of the linden, willow, &c. was of
the same quality throughout. As to the second inquiry, it is hardly
necessary to repeat, that for the complete and thorough carbonization
of the wood, to produce at the same time coal of a uniform quality,
the process of charring in iron cylinders or close vessels, is to
be preferred. The point to be attended to is, to bring the wood to
a complete state of ignition, and consequently to disengage all the
volatile or fluid parts. When the gas (carburetted hydrogen) ceases
to appear, it is a criterion that the operation is finished. This
gas, it is to be recollected, will come over even after the whole
of the wood is completely ignited. The first volatile product is
the pyroacetic acid. Some saturate the acid liquor with chalk, and
decompose the acetate of lime with sulphate of soda, and separate the
acetic acid from the acetate of soda by distillation with sulphuric
acid. The acetic acid is then tolerably pure, and may be diluted for
use.
It is observed, however, that when charcoal, prepared in iron
cylinders, is designed for gunpowder, the last portion of vinegar
and tar must be allowed to escape, and the reabsorption of the
crude vapours prevented, by cutting off the communication between
the interior of the cylinders and the apparatus for condensing the
pyroacetic acid, whenever the fire is withdrawn from the furnace. If
this precaution be not taken, the gunpowder made with the charcoal
would be of inferior quality.
On a large scale, when the object is also to prepare the vinegar of
wood, a series of cast-iron cylinders, about four feet diameter, and
six feet long, are built horizontally, in brick-work, so that the
flame of one furnace may play round about two cylinders. Both ends
project a little from the brick-work. One of them has a disc of cast
iron well fitted and firmly bolted to it, from the centre of which
disc an iron tube about six inches diameter proceeds, and enters at
a right angle, the _main_ tube of the refrigeration. The diameter
of this tube may be from 9 to 14 inches, according to the number of
cylinders. The other end of the cylinder is called the mouth of the
retort. This is closed by a disc of iron, smeared round the edge,
with clay lute, and secured in its place by wedges. The charge of
wood for such a cylinder is about 8 cwt. The hard woods, oak, ash,
birch, and beech, are alone used. Fir does not answer. The heat is
kept up during the day-time, and the furnace is allowed to cool
during the night. Next morning the door is opened, the coal removed,
and a new charge of wood is introduced. The average product of
crude vinegar is 35 gallons. Its total weight is about 300 lbs. But
the residuary charcoal, according to Ure, (_Chemical Dictionary_),
from whom we have taken this account, is found to weigh no more
than one-fifth of the wood employed. The crude pyroacetic acid is
rectified by a second distillation, in a copper still, in the body of
which about 20 gallons of viscid tarry matter are left for every 100.
Its acid powers are now superior to the best household vinegar in the
proportion of 3 to 2. Ure observes, that by distillation, saturation
with quicklime, evaporation of the liquid acetate to dryness, and
gentle torrefaction, the empyreumatic matter is so completely
dissipated, that on decomposing the calcareous salt by sulphuric
acid, a pure, perfectly colourless, and grateful vinegar rises in
distillation. Pyroacetic acid is said to be a powerful antiseptic. M.
Monge, Dr. Jorg, and more lately, Mr. Ramsay, of Glasgow, have made
experiments with it. Fish dipped in it have been preserved for many
days, and meat treated in the same manner, has also been preserved
from putrefaction.
With respect to the pulverization of charcoal, the operation is
so exceedingly simple, that we deem it unnecessary to notice it.
It is obvious, that mortars, mills, &c. may be used, with fine or
coarse sieves. For fire-works, charcoal is frequently pulverized
in a leather sack, in the same manner as grained powder is reduced
to meal-powder. It may be made either coarse or fine, to answer
different purposes, by employing sieves of different kinds. Charcoal
may be separated from nitre and sulphur, in gunpowder, by a simple
process, which may be seen by referring to the section on gunpowder.
The quantity of carbon in coal, is directly proportionate to the
quantity required for the decomposition of nitrate of potassa, a fact
necessary to be considered in the theory of the action of charcoal
in gunpowder. Thus, Mr. Kirwan found that, 12.709 of carbon are
necessary to decompose 100 of nitrate of potassa. It will be easy
to deduce the quantity of carbon, in a given weight of coal, from
the quantity of nitrate of potassa it is capable of decomposing. The
experiment is made very readily by fusing in a crucible, five hundred
or more grains of nitre, and when red-hot projecting by degrees the
powdered coal on the nitre. When the detonation produced by one
projection of coal has ceased, add a new portion till it produces no
farther effect.
Charcoal may be made intensely black, resembling ivory
black, according to M. Denys-de-Montfort, (_Bibliothèque
Physico-Economique_, for March 1815,) by pulverizing it very fine,
mixing it with wine lees, and drying the mixture, and then subjecting
it to a strong heat in a covered crucible, or other vessel.
_Sec. VII. Of Gunpowder._
Having remarked, that the quality of gunpowder depends upon the
purity of the materials, of which it is formed, and that they
should be prepared in a state of purity; the subject that will
now particularly claim our attention, is the proportions of the
ingredients, their mixture, and the final preparation of gunpowder
for use. To this, we purpose to add, the theory of its explosive
effects, the different modes of proving it, and the experiments
necessary to determine the quality of its respective ingredients,
on all which we will be as brief as the importance of the subjects
will admit. Previously, however, it may be interesting to notice the
_history of gunpowder_, the invention of which has so completely
changed the art of war.
The history of gunpowder has been fully treated by many writers of
eminence; but by none more largely, and, at the same time, more
satisfactorily than by the French. Beckman, in his History of
Inventions, is full on this subject. Our purpose is not to go into
details, as it would enlarge our volume, to the exclusion, perhaps,
of other and more important matter. We shall, therefore, confine
ourselves to a few facts and observations.
Notwithstanding much has been written on the subject, the original
invention of gunpowder seems to be in obscurity. By whom, and at what
time it was invented, is a question not fully settled. It is said to
have been known in the east from time immemorial, and whatever claim
Roger Bacon, who died in 1292, may have had to the discovery, or that
he knew the properties of gunpowder, it is certain, that the use of
fire-arms was then unknown in Europe.
Professor Beckman, who examined all the authors extant on the origin
of gunpowder, is of opinion, that it was invented in India, and
brought by the Saracens from Africa to the Europeans, who improved
the preparation of it, and employed it in war, as well as for small
arms and cannon.
M. Langles, who read a memoir on this subject to the National
Institute, in 1798, observes, that the Arabians obtained a knowledge
of gunpowder from the Indians, who had been acquainted with it from
the earliest periods. The use of it was forbidden in their sacred
books, the veidam or vede. It was employed in 690 at the battle near
Mecca. As nitre was employed in all probability in the Greek fire,
invented about the year 678, it is supposed, that that composition
gave rise to the invention of gunpowder.
Various prescriptions, or formulæ, have been given for the
preparation of this fire. The oldest is by princess Anna Commena,
in which, however, there is only resin, sulphur, and oil. Beckman
observes, that the first certain mention of saltpetre will be found
in the oldest account of the preparation of gunpowder, which, in
his opinion, became known in the thirteenth century, about the same
time that the use of the Greek fire, of which there were many kinds,
began to be lost. The oldest information on this subject is to be
found in the works of Albertus Magnus, and the writings of Roger
Bacon. The true recipe for making the Greek fire, and the oldest for
gunpowder, were found in a manuscript, preserved in the electoral
library at Munich. Various copies of this manuscript were made. Bacon
employed this writing, which was mentioned by Jebb, in the preface
to his edition, from a copy preserved in the library of Dr. Mead.
Whether the writer was Marcus Græcus, is of no moment; for Cardan
observes, that the _fire that can be kindled by water_, or rather not
extinguished by water, was prepared by Marcus Gracchus.
The former Marcus, mentions two kinds of fire-works; and the
composition, which he prescribes for _both_, is two pounds of
charcoal, one pound of sulphur, and six pounds of saltpetre, well
powdered and mixed together in a stone mortar.
Friar Bacon, who lived three centuries after Græcus, was in
possession of the recipe. It was concealed, however, from the people,
veiled in mystery. In his treatise _De Secretis Operibus Artis et
Naturæ, &c._ the secret of the composition is thus expressed: "sed
tamen salispetræ, LURU MOPE CAN URBE et sulphuris; et sic facies
tonitrum et corruscationem, si scias artificium." _Luru mope can
urbe_, is the anagram for _carbonum pulvere_. Bacon supposes, that it
was with a similar composition that Gideon defeated the Midianites,
with only three hundred men. Besides the use of gunpowder in the 9th
century, in the war between the Tunisians and the Moors, in which the
former are said to have employed "certain tubes or barrels, wherewith
they threw thunderbolts of fire," the Venetians employed it against
the Genoese, and it was reprobated as a manifest contravention of
fair warfare.
Peter Mexia, in his "_Various Readings_," relates, that the Moors,
being besieged, in 1349, by Alphonso the eleventh, king of Castille,
discharged a kind of iron mortars upon them, which made a noise like
thunder. This, with the sea-combat between the Tunisians and the
Moors, stated on the authority of don Pedro, bishop of Leon, places
the invention much earlier than by some writers.
Polydore Virgil ascribes the invention of gunpowder to a chemist,
who, having put some of his composition in a mortar, and covered it
with a stone, was blown up, in consequence of its accidentally taking
fire. The person here alluded to, according to Thevet, was a monk of
Friburg, named Constantine Anelzen. Others, as Belleforet, with more
probability, hold it to be Bartholodus Schwartz, or the black, who
discovered it, as some say, about the year 1320. Du Cange, however,
remarks, that there is no mention made of gunpowder in the registers
of the chamber of accounts in France, as early as the year 1338.
Roger Bacon knew of gunpowder, near one hundred years before Schwartz
was born. (See the invention of cannon, in _military fire-works_,
fourth part.)
It is certain, that Albert de Bollstædt indicated the constituent
parts of gunpowder, when he says, in his _Mirabilis Mundi_, "Ignis
volans, accipe libram unam, sulphuris, libras duas, carbonas salicis,
libras sex, salis petrosi, quæ tria subtilissime terantur in lapide
marmorea; postea aliquid posterius ad libitum in tunica de papyro
volante, vel tonitrum faciente ponatur.
"Tunica ad volandum debet esse longa, gracilis, pulvere illo optime
plena, ad faciendum vero tonitrum brevis, grossa et semiplena."
Gunpowder was of a much weaker composition than that now in use, or
that described by Marcus Græcus. Tartalgia, (_Ques. and Inv._ lib.
3, ques. 5), observes, that, of twenty-three different compositions,
used at different times, the first, which was the oldest, contained
equal parts of the three ingredients. When guns of modern
construction came into use, gunpowder of the present strength was
introduced.
The strength of powder depends upon the proportions of the
ingredients, they being pure; and Mr. Napier observes, (_Trans. Royal
Irish Academy, ii._) that the greatest strength is produced, when
the proportions are, nitre, three pounds, charcoal, nine ounces, and
sulphur, three ounces. The cannon powder was in meal, and the musket
powder in grain.
In the time of Tartalgia, the cannon powder was made of four parts of
nitre, one of sulphur, and one of charcoal; and the musket powder of
forty-eight parts of nitre, seven parts of sulphur, and eight parts
of charcoal; or of eighteen parts of nitre, two parts of sulphur, and
three parts of charcoal.
The intimate mixture, therefore, and the determinate proportions
of saltpetre, charcoal, and sulphur, form gunpowder; the different
qualities of which, depend, as well upon the proportions which are
used, as on the purity of the materials, and the accuracy with which
they are mixed.
Gunpowder is reckoned to explode at about 600° Fahr; but, if heated
to a degree just below that of faint redness, the sulphur will mostly
burn off, leaving the nitre and charcoal unaltered.
The saltpetre should be perfectly refined, and entirely free from
deliquescent salts; the sulphur as pure as possible, and, for that
reason, a preference should be given, to that which is sublimed, or
distilled; and the charcoal should be prepared in iron cylinders, as
described under that head, from woods, which are light and tender, as
the linden, willow, hazle, dogwood, etc.
There is a considerable difference in the proportions used by
different nations; but, from the many accurate and conclusive
experiments of the French chemists, their formula is certainly the
most perfect. In English powder, three-quarters of the composition
are nitre, and the other quarter is made up of equal parts of
charcoal and sulphur; but sometimes, to seventy-five parts of nitre,
fifteen of charcoal is used, adding ten of sulphur. Their government
powder is the same for cannon, as for small-arms.
According to a number of experiments, made at Grenille, it was
found, that the proportion of saltpetre in gunpowder, must be in a
given ratio with the charcoal, so that the latter might effectually
decompose it in the act of combustion; and hence the ratio is as 12
of the latter to 75 of the former, and these, with 12 of sulphur, are
the proportions generally employed. Ruggeri (_Pyrotechnie Militaire_,
p. 91,) gives, as the proportions, 12 parts of saltpetre of the third
boiling, 2 parts of charcoal, and 1 part of sulphur. The proportions,
used in Sweden, are 75 saltpetre, 9 sulphur, and 16 charcoal; in
Poland, 80 saltpetre, 8 sulphur, and 12 charcoal; in Italy, 76
saltpetre, 12 sulphur, and 12 charcoal; in Russia, 70 saltpetre, 11
sulphur, and 18-1/2 charcoal; in Denmark, 80 saltpetre, 10 sulphur,
and 10 charcoal; in Holland, 76 saltpetre, 12 sulphur, and 12
charcoal; in Prussia and Austria, 78 saltpetre, 11 sulphur, and 11
charcoal; and in Spain, 77 saltpetre, 11-1/2 sulphur, and 11-1/2
charcoal.
According to Klaproth and Wolff, (_Dictionnaire de Chimie_,
translated into French by MM. Lagrange and Vogel), Berlin powder
is composed of three-quarters nitre; one-eighth sulphur, and
one-eighth charcoal; Chinese powder, of 16 parts nitre, 6 charcoal,
and 4 sulphur; Swedish powder, of 75 parts nitre, 16 sulphur, and
9 charcoal; the powder of Lissa, of 80 nitre, 12 sulphur, and 8
charcoal; and English powder, on the authority of Beckman, as
follows: Powder for war, 100 parts of nitre, 25 charcoal, and 25
sulphur; musket powder, 100 nitre, 18 sulphur, and 20 charcoal;
pistol powder, 100 nitre, 23 sulphur, and 15 charcoal; strong cannon
powder, 100 nitre, 20 sulphur, and 24 charcoal; strong musket powder,
100 nitre, 15 sulphur, and 18 charcoal; and strong pistol powder,
100 nitre, 10 sulphur, and 18 charcoal. German powder, for war, is
composed, generally, of 0.70 saltpetre, 0.16 charcoal, and 0.14
sulphur. A small portion of gum is sometimes added, to make the grain
firmer; but such additions retard the combustion, and the effect.
The addition of gum arabic, however small, must injure the quality of
gunpowder, although it has the effect of making the grain firmer, and
less liable to fall into meal powder. The grain is also made heavier,
and less liable to absorb moisture. M. Proust, in his second memoir
on gunpowder, mentions the use of icthyocolla, a fish glue, for the
same purpose; and, nevertheless, speaks of some advantages that the
gunpowder, prepared with it, possesses.
It is observed by Mr. Coleman, of the Royal Powder Mills of Waltham
abbey, that it is not exactly ascertained, whether there is any
one proportion, which ought always to be adhered to, and for every
purpose. We have no hesitation in believing, for our own part, that
the French formula is the most correct, from the numerous experiments
made at the royal manufactory at Essone, near Paris.
A very considerable variation is found in the proportions of the
ingredients of the powder of different nations and different
manufactories. The powder made in England, is the same for cannon as
for small arms, the difference being only in the size of the grains;
but in France, it appears, that there were formerly six different
sorts manufactured; namely, the strong and the weak cannon powder,
the strong and the weak musquet powder, and the strong and the weak
pistol powder. The following are the proportions in each, though the
reason of this nicety of distinction is not very obvious. For the
strong cannon powder, the nitre, sulphur, and charcoal were in the
proportions of 100 of the first, 25 of the second, and 25 of the
third: for the weak cannon powder, 100, 20, and 24: for the strong
musket powder, 100, 18, and 20; for the weak, 100, 15, and 18: for
the strong pistol powder, 100, 12, and 15; for the weak, 100, 10, and
18.
The Chinese powder appears, by the analysis of Mr. Napier, to be
nearly in the proportions of 100 of nitre, 18 of charcoal, and
11 of sulphur. This powder, which was procured from Canton, was
large-grained, not very strong, but hard, well coloured, and in very
good preservation.
The following proportions are _now_ used in France, for the
manufacture of gunpowder for war, for hunting, and for mining.
For war. For the chase. For mining.
Saltpetre, 75.0 78 65.
Charcoal, 12.5 12 15.
Sulphur, 12.5 10 20.
After having made choice of the materials, the nitre being
pulverized, is passed through a brass sieve; the sulphur is
pulverized by means of a muller, or other contrivance, and also
sifted in a bolter; the quantities are then weighed, as well as the
charcoal.
The mixing of these substances is performed in a series of mortars,
hollowed out of a strong piece of oak wood; and by the aid of
pestles or stampers, which are set in motion by machinery and water
power, the mixture is thoroughly made. The end of the stampers is
usually covered with, and sometimes made of, brass, and the mortars
are also, in some powder mills, lined with brass. The mill has
generally two rows of mortars and stampers, of ten each. The nitre,
sulphur, and charcoal, in proper proportions, are put into each
mortar. The charcoal is first introduced into the mortar, being
sometimes previously pulverized; then wetted with water, and the
pounding is continued for thirty minutes. The nitre and the sulphur
are then added, and the whole is stirred with the hand. More water
is then added; it is again stirred, and the operation of pounding
is continued. The object of adding the water is to prevent the so
called volatilization of the ingredients, and to give the mixture the
consistency of paste, and at the same time to prevent the explosion
of the powder; a circumstance, which must be always guarded against.
After the operation is continued for half an hour, the pounders are
stopt, and the powder is then _re-exchanged_ by means of copper
or brass ladles; that is to say, the powder of the first mortar is
removed, and put into a box, and the contents of the second mortar
are put into the first, that of the third is put into the second,
that of the fourth into the third, &c. in succession, and in the
last, the contents of the first mortar.
We make, in this manner, twelve exchanges, allowing one hour between
two, and adding water from time to time, to the mixture, and
especially during the summer months. After this, the pounders are
again set in motion, for the space of two hours, and the operation
is finished. Fourteen hours are generally required to complete the
mixture, which is then in the form of paste. It is then granulated.
After being partially dried, the graining is performed by passing it
through sieves, which are more generally formed of parchment. These
sieves are made to work horizontally, and the powder is caught in
vessels placed beneath. The size of the grain depends on the sieve;
hence, fine grain, or coarse grain powder is thus obtained. In the
sieve is usually placed a contrivance to break the masses, and to
cause the powder to pass through in grains. After this, the powder
is again passed through a second sieve, commonly called a _grainer_,
the holes of which are of the same diameter as the powder we wish
to obtain. It is then put into another sieve, which permits only
the dust to pass, whilst the grain-powder remains. As the powder,
however, contains some grains too large, as well as others too small,
we may separate the former by a fourth sieve, of a suitable size.
The dust and fine grain are carried to the mill, and worked over.
The powder for war, and for mining, is dried immediately after the
graining.
Formerly, the powder was dried in the open air, by spreading
it on tables lined with cloth, or in oblong boxes; but serious
inconveniences resulted from it, and, particularly, the powdermakers
were obliged to watch the temperature, as well as the state of the
atmosphere. When the latter was moist, the _drying_ was suspended.
M. Champy, however, has obviated these inconveniences by a very
advantageous process, which consists in raising the temperature of
the air to 50 or 60 degrees, and causing it to pass from the chamber
in which it is heated, through cloths, on which is spread a bed of
powder, of a certain thickness. By this means, large quantities of
powder may be dried, in all seasons of the year, in a short time, and
at little expense. In whatever manner the _drying_ is performed,
there is always more or less _dust_ formed, which, to make the grain
of one uniform appearance, must be separated by a hair sieve. This
operation is called the _dusting_.
Whether we adopt the plan recommended by M. Champy, or heat the rooms
for the drying of powder to a certain temperature, by means of steam
pipes, a plan which presents every advantage, or use the old mode,
the effect is the same.
The musket, or _hunting powder_, undergoes an operation more than the
powder for war, namely, that of glazing, which is performed before it
is dried. With the exception of this process, it is made in the same
manner, using, however, a finer sieve in granulating it. The glazing
has for its object the smoothing, or removing the asperities of the
grain, and to prevent its falling into dust, and soiling the hands.
The powder intended for glazing is first exposed an hour to the
sun on one cloth, in winter, and between two cloths in summer, in
order to dry it more perfectly, which is very necessary before the
operation of glazing. For this purpose, it is put into a vessel like
a barrel, which is turned horizontally upon its axis, by machinery.
This barrel is furnished with bars that go across, intended to
augment the friction, or rubbing of the grain, and expedite the
process. The barrels are made to turn slowly, to avoid breaking the
grain, and at the expiration of eight or twelve hours, the glazing
is finished, the powder having acquired a sufficient hardness and
polish. After removing the powder, the dust is separated in the usual
manner.
_Gunpowder-mills_ are mills, in which powder is prepared, by pounding
and beating together the ingredients of which it is composed. They
are always worked by water-power, and as there are generally many
of them belonging to the same manufactory, one dam of water will
furnish a sufficient supply. In the construction of powder-mills, the
frame of the house is made very stout, and the roof put on lightly,
so that in case of explosion, it may be carried off easily, and
thus give vent to the powder, without much injury to the works. The
lights, to enable the work to be carried on at night, are placed on
the outside of the building, beyond the reach of the powder, and
by means of glass windows, the light passes into the mill. It is
lamentable, indeed, that so many accidents occur in the operation
of making powder. This may take place, as it has to our knowledge,
by the friction of the pounders. Their weight, the rapid succession
of the blows, and the dryness of the powder, are the principal
causes of such accidents, and sometimes by the inattention of the
workmen, suffering nails, and the like, to get among the materials.
I once witnessed the effect of an explosion of the kind, in the
neighbourhood of Frankford, in the vicinity of Philadelphia, at the
old and well-known powder mills, at that place. It was produced, in
consequence of the friction, by the neglect of the men not adding
water at a proper time, to keep the materials moist. The mill in
which the explosion took place was not much injured; but the roof,
together with the men, were sent a considerable distance. Some of the
latter fell into the mill-race, and were much injured. The effect,
however, did not stop here; for the fire communicated, strange as it
may appear, to some of the other mills, although at some distance,
and blew them up. Several explosions have happened at the same mills.
An experiment, made at the same works, by the then proprietor,
the father of the late commodore Decatur, by putting the nitre,
charcoal, and sulphur, into a barrel, with iron balls covered with
lead, which was turned upon its axis, terminated in the same way.
It exploded, but no other injury or accident was sustained. On
examining the balls, we found, that the lead was entirely worn off,
and the explosion must have been owing to the iron. This experiment
was performed, in order to find if the mixture could be made in this
manner, a plan which was afterwards adopted in France, with success,
but brass balls were used. In a series of essays, which I wrote
for, and published in, the Aurora, in 1808, on the "_Application
of Chemistry to the Arts and Manufactures_," as manufactures are
vitally important to the _practical_ independence of this country,
I mentioned the subject of gunpowder, and the different modes of
preparing it, and among which, the various experiments on this
subject.
The machinery, required in gunpowder mills, is exceedingly simple.
The power of the water, which may be given by an overshot, or
undershot wheel, is communicated to the parts of the mill, which
perform the work. Thus it is, that pounders, like the snuff, or
plaster-paris mill, are put in motion, by a horizontal shaft,
furnished, at different distances, with pieces of wood, which, by the
revolution of the shaft, and meeting with the projecting pieces from
the pounders, raises them in succession. They fall, then, in the same
order of succession, in the respective mortars.
The mortars of the powder-mill, are hollow pieces of wood, capable
of holding twenty pounds of paste, composed of the substances before
mentioned, which are incorporated by means of the pestle. There are
usually twenty-four mortars in each mill, where are made, each day,
four hundred and eighty pounds of gunpowder; care being taken, to
sprinkle the ingredients with water, from time to time, lest they
should take fire. This precaution is absolutely necessary, and if
attended to, would prevent many of the explosions, which, unhappily,
take place, in the manufacture of powder. The friction must be
great, and, therefore, the increase of temperature, occasioned in
this manner, ought to be guarded against. This can only be done, by
diminishing the time, or number of the blows, or by proportioning
the weight of the pestle, and the frequent addition of water. The
last is the most certain, and indeed, the water is in some respects,
necessary to promote a more intimate mixture of the materials. The
observations of M. David, on the use of water in the manufacture of
powder, are certainly correct. The pestle is a piece of wood, ten
feet high, and four and a half inches broad, armed at the bottom with
a round piece of metal. It weighs about sixty pounds.
Having mentioned one cause of the explosion of powder-mills, that
of friction produced by the pestle, we find that it has been
accounted for on another principle. The _Annales de Chimie_, tome
xxxv, mentions some instances of spontaneous combustion in powder
mills. It is well known, that charcoal has the property of absorbing
several gases, and the observations of Rouppe and Berthollet, on
this subject, are conclusive. It is also known, that charcoal, which
contains hydrogen, when exposed to atmospheric air, will absorb
oxygen, and form water; and during this combination, heat must be
generated, by the emission of caloric from the oxygen gas. It is
said, then, that in cases of spontaneous combustion, when nitre,
sulphur, and charcoal, are mixed together, (unless water be added to
prevent it), this effect will ensue, and fire be produced. We know,
however, that percussion is one source of heat; and in truth, if that
opinion be well founded, percussion itself may facilitate the union
of hydrogen, with the oxygen of the air, and necessarily operate as a
secondary cause of such explosions.
Another opinion has been advanced by Bartholdi, to account for
the spontaneous combustion in powder mills: namely, that charcoal
sometimes contains phosphorus, combined with hydrogen, which, by the
action of the pestle, is disengaged in the form of gas, and inflames,
the moment it comes in contact with the air. Others again suppose,
that it sometimes contains pyrophorus.
Pulverizing the charcoal, in the first instance, by itself, and
adding water, during its mixture, from time to time, a measure
proposed in 1808, by M. David, and now generally adopted, will
prevent such accidents; for it appears, they have not occurred in
France, since the adoption of this plan. Some remarks on spontaneous
combustion, may be seen in the article on _artificial volcanoes_.
M. Sage, (_Journal de Physique_, vol. lxv, p. 423, or _Nicholson's
Journal_, vol. xxiii, p. 277), has written on the spontaneous
ignition of charcoal, and adduced some facts on the subject; by which
it appears, that M. de Caussigni was the first, who observed, that
charcoal was capable of being set on fire, by the pressure of mill
stones.
Mr. Robin, commissary of the powder mills of Essonne, has given an
account, in the _Annales de Chimie_, of the spontaneous inflammation
of charcoal, from the black berry bearing alder, that took place
the 23d of May, 1801, in the box of the bolter, into which it had
been sifted. This charcoal, made two days before, had been ground in
the mill, without showing any signs of ignition. The coarse powder,
that remained in the bolter, experienced no alteration. The light
undulating flame, unextinguishable by water, that appeared on the
surface of the sifted charcoal, was of the nature of inflammable gas,
which is equally unextinguishable.[17]
The moisture of the atmosphere, of which fresh made charcoal is
very greedy, appears to have concurred in the development of the
inflammable gas, and the combustion of the charcoal.
It has been observed, that charcoal powdered and laid in large heaps,
heats strongly.
Alder charcoal has been seen to take fire in the warehouses, in which
it has been stored.
About thirty years ago, M. Sage saw the roof of one of the low wings
of the mint set on fire by the spontaneous combustion of a large
quantity of charcoal, that had been laid in the garrets.
Mr. Malet, commissary of gunpowder at Pontailler, near Dijon, has
seen charcoal take fire under the pestle. He also found, that when
pieces of saltpetre and brimstone were put into the charcoal mortar,
the explosion took place between the fifth and sixth strokes of the
pestle. The weight of the pestles is eighty pounds each, half of this
belonging to the box of rounded bell metal, in which they terminate.
The pestles are raised only one foot, and make forty-five strokes in
a minute.
"In consequence of the precaution now taken," M. Sage observes,
"to pound the charcoal, brimstone, and saltpetre separately, no
explosions take place; and time is gained in the fabrication, since
the paste is made in eight hours, that formerly required four
and-twenty.
"Every wooden mortar contains twenty pounds of the mixture, to which
two pounds of water are added gradually. The paste is first corned:
it is then glazed, that is, the corns are rounded, by subjecting them
to the rotary motion of a barrel, through which an axis passes: and
lastly, it is dried in the sun, or in a kind of stove.
"Experience has shown, that brimstone is not essential to the
preparation of gunpowder; but that which is made without it falls
to powder in the air, and will not bear carriage. There is reason
to believe, that the brimstone forms a coat on the surface of the
powder, and prevents the charcoal from attracting the moisture of the
air.
"The goodness of the powder depends on the excellence of the
charcoal; and there is but one mode of obtaining this in perfection,
which is distillation in close vessels, as practised by the English.
"The charcoal of our powder manufactories is at present prepared in
pots, where the wood receives the immediate action of the air, which
occasions the charcoal to undergo a particular alteration."
In 1724, (_Coll. Academ._ t. v, p. 413,) M. de Moraler proposed a new
mode of mixing the materials for gunpowder. In 1759, M. Musy proposed
another method to prevent explosions; and in 1783, the baron de
Gumprecht constructed a very ingenious powder mill, a model of which
he presented to the king of Poland, whose approbation it received.
There is an account in detail, of the results of the experiments made
by MM. Regnier and Pajot Laforet, with different fulminating powders,
in the _Archives des Découvertes_, iii, p. 337. These experiments,
although interesting in a philosophical view, cannot be of service in
the present case. They were made with gunpowder, fulminating silver,
fulminating silver and mercury combined, fulminating mercury alone,
&c. See also the _Bulletin de la Société d'Encouragement, cahir 65_.
The observations of M. Proust (_Journal de Physique_ for May,
1815) on the mixing of powder, and the consequences that result by
following the old process, may be consulted.
The process of manufacturing gunpowder, which we have described, is
followed in all, or the greater part of the factories of France. It
is, however, tedious, and not exempt from danger. The same process,
with some modifications or improvements, is adopted in this country;
but of all our gunpowder manufactories, that of the messrs. Dupont
of Brandywine, Delaware, has heretofore produced the best powder.
Powder, however, equally powerful, has been made in other factories.
The improved process of M. Champy, which, in many respects, is
superior to the foregoing, is the following:
1. The nitre, sulphur, and charcoal are first reduced, separately,
to very fine powder. This operation is performed in barrels, which
are made to turn upon their axis, similar to the barrel-churn, and
the substances are introduced gradually. Balls, made of an alloy of
copper and tin, are then put in, which by their action reduce the
substances to powder.
2. The second operation has for its object, the intimate mixture of
the ingredients. The quantities to be mixed are weighed, and put
into a drum with a quantity of shot, which is made to revolve during
an hour and a quarter. In this manner, three hundred pounds of the
mixture are at once operated upon.
3. The mixture is then moistened with water. About fourteen per cent.
is added. It is then passed through a sieve made with round holes,
and then put into a drum, and submitted for a half hour, to a rotary
motion. A number of small round grains are thereby formed, which are
separated from the mass by means of a sieve, the holes of which are
very small.
4. When a sufficient quantity of these grains are procured, they are
put into another drum, of a suitable size, with one and a half times
their weight of the original mixture. The drum being put in motion,
some water is added, which serves to make them increase in size, by
constant rubbing: at the end of a certain time, the whole becomes
granulated, or perfectly round. The density of the grains depends on
the mixture, and the time they were kept in motion.
5. The powder being thus grained, is passed through sieves, whose
holes are of different diameters; and hence it is divided into three
kinds: _viz._ cannon powder, musket powder, and fine grained powder.
6. Finally, the powder is dried, and preserved in the usual manner.
Its strength is equal to that made by the old process, and is
perfectly round.
It may be proper to observe, that this process presents many
important and decided advantages. Although, in our description, we
have not gone into details, yet the whole operation will be seen at
one view. It was practised in France, by its inventor, M. Champy,
and, besides being introduced into the United States, it has also
been adopted in Prussia.
M. Proust endeavoured to show, that charcoal made of shoots or
branches, makes the best powder, and will mix with more facility with
the nitre and sulphur; and in employing the ordinary charcoal, two
hours beating is necessary to obtain a perfect mixture. The pestles,
as Chaptal observes, usually make fifty-five strokes in a minute.
Their weight is various; he gives them at eighty pounds.
M. Carney discovered a new process for the fabrication of powder,
and although Chaptal himself made some advantageous changes in the
process, yet the merit of the discovery he gives entirely to Carney.
The process of M. Champy, is in some particulars the same. It will be
sufficient, however, to observe, that it is reduced to three heads:
_viz._
1. The pulverization, and sifting of the materials;
2. Mixing the materials intimately in vessels similar to casks; and,
3. Giving the mixture the necessary consistence, and the final
granulation.
For some details of the process, the reader may consult Chaptal's
_Chimie Appliqué aux Arts_, tome iv, p. 145.
Chaptal is of opinion, that Carney's mode of fabricating powder,
presents many advantages, among which he considers the facility of
its formation, economy in the expense, and the superiority of the
powder. In a memoir on the subject, and the formation of powder at
Grenelle, Chaptal has described the process very minutely.
Bottée and Riffault reduce the manufacture of gunpowder in France to
the following heads:
1. The mixture of the ingredients. This relates to the manner of
uniting the nitre, charcoal, and sulphur, the quantity of the
composition put into each mortar, and observations respecting the
manipulation.
The time required for reducing gunpowder to its proper consistency,
and for effecting the mixture is termed by the French, _Battage_.
They are usually twenty-four hours, (or eight according to the new
mode,) in pounding the materials to make good gunpowder. Supposing
the mortar to contain sixteen pounds of composition, it would require
the application of the pestle 3500 times each hour.
The order in which they are beaten, and mixed, is as before given,
and also the rechanging, or transferring the materials from one
mortar to another.
2. _Granulation_, (_Grenage Fr._) This operation consists, as before
observed, in passing the mixture through different sized sieves,
employing also parchment sieves, and afterwards separating the
dust by a fine sieve. The size of the grain depends altogether on
the sieve. Hence we have cannon-powder, gunning or musket-powder,
pistol-powder, and mining-powder. Superfine powder is the very small
grained.
3. _Glazing._ (_Lissage Fr._) This operation takes off the asperities
of the grain, renders it hard and less liable to soil the hands, and
gives it a kind of lustre. It is only used for fine powder, such as
the pistol, and hunting-powder. Cannon powder is never glazed. It is
performed in a barrel-shaped vessel, which is made to revolve on its
axis, like the ordinary barrel-churn. The quantity of powder glazed
in one of these barrels at a time, in France, is 150 kilogrammes.
By the rotary motion, the grains of powder rub against each other,
by which each grain becomes smooth, and receives a polish. According
to the motion of the barrel, so is the glazing more perfect. This,
however, is regular. After the operation, which continues several
hours, the dust is separated from the grain by a sieve. The state of
the atmosphere influences the process. If dry, the grain receives a
better polish; if wet or damp, the operation is retarded, and the
gloss imperfect. It has been customary to introduce a very small
portion of finely pulverized plumbago, (carburet of iron), in order
to give the grain a better polish. But such additions, however small,
are obviously injurious to the powder. It is said that it prevents
the absorption of moisture. Powder, which has been glazed with black
lead, (plumbago), may be known by its peculiar shining lustre, and
also by experiment. M. Cagniard Latour made some experiments with
glazed powder, which may be seen in the work of Bottée and Riffault,
p. 233.
4. _Drying._ (_Séchage. Fr._) The drying of powder is performed in
two ways, _viz._ by exposure to the sun, and by exposure to heat in
close rooms. The English mode, that of drying by steam pipes, MM.
Bottée and Riffault are of opinion, presents many advantages, and
particularly that the powder may be dried in all weathers, and with
perfect safety.
The mode of drying gunpowder by the vapour of water, (confining
it, however, in iron pipes or vessels,) was suggested in 1781, and
1787. See _Mémoires de l'Académie des Sciences de Suede_, 1781, the
_Journal des Savants_, 1787, and the _Transactions of the Society of
Arts_, vol. xxiv. Mr. Snodgrass, in the last work, gave an account of
a method of communicating heat by steam, by using pipes of cast iron,
for which the society of arts voted him forty guineas.[18] Chaptal
(_Elements de Chimie_) has some judicious remarks on the exsiccation
of powder.
The experiment made at Essonne near Paris, by M. Champy, in 1808,
on a contrivance for the drying of powder, was satisfactory. This
experiment may be seen in page 242 of Bottée and Riffault.
5. Dusting, (_Epoussetage_.) This operation is confined merely to the
sifting. It is nothing more than the separation of the dust from the
grain, which we have before noticed. The dust is put in the mortars,
and worked over.
6. _Barrelling &c._ After the powder has gone through the several
operations described, it is then put into barrels, and taken to the
magazine.
After speaking of gunpowder under these heads, they describe the
manner of treating the green, (_verd_) and dry meal powder; the
police of powder establishments, for order and economy; the workmen
necessary in a powder manufactory;[19] the process of making powder
in the revolution; and for the manufacture of _imperial powder_
(which contains 0.78 saltpetre 0.10 sulphur, and 0.12 charcoal); the
process of Berne, where the powder is made of 0.76 saltpetre, 0.14
charcoal, and 0.10 sulphur; the process of Mr. Champy, noticed in
this article; observations respecting different processes; on powder
magazines; gunpowder made of other saline substances besides nitre;
different modes of proving powder, examination of powder; description
of workshops, mechanics, and utensils, &c. &c. with a variety of
engravings. We have merely to remark, that this work of Bottée and
Riffault (a large quarto volume, of 340 pages, besides the plates,
which make a distinct volume) ought to be in the possession of every
gunpowder manufacturer, as it contains all the information known on
that subject. Of this fact there can be no difference of opinion,
that in consequence of the great attention paid to the subject of
gunpowder in France, not only by the government, but by scientific
associations and individuals, their knowledge generally must be more
minute and accurate, and their works, as authentic records of facts,
_more to be depended on_.
Besides many interesting works, and memoirs in French,[20] there have
appeared some valuable dissertations in the English language. Mr.
Coleman, in his paper in the Phil. Mag. ix, p. 355, may be considered
the first, who, as superintendant of one of the Royal powder mills,
was enabled to present a body of facts on this subject.
As the mode of manufacturing gunpowder at the Royal Powder Mills
of Waltham Abbey, in England, may be interesting and useful, in
connection with the different processes already given; we will
introduce in this place the account of Mr. Coleman, having extracted
it from the _Artist's Manual_, &c. of the author, and having taken it
from the original memoir of that gentleman.
The ingredients of gunpowder are taken in the following proportion,
namely, 75 of saltpetre, 15 of charcoal, and 10 of sulphur. The
saltpetre used is almost entirely that which is imported from the
Indies, which comes over in the rough state mixed with earthy
and other salts, and is refined by solution, evaporation, and
crystallization. After this it is fused in a moderate heat, so as
to expel all the pure water, but none of the acid, and is then fit
for use. The great use of refining the nitre is to get rid of the
deliquescent salts, which by rendering the powder made of it liable
to become damp by keeping, would most materially impair its goodness.
The sulphur used is imported from Italy and Sicily, where it is
collected in its native state in abundance. It is refined by melting
and skimming, and when very impure, by sublimation. It should seem
that the English sulphur, extracted in abundance from some of the
copper and other mines, is too impure to be economically used for
gunpowder, requiring expensive processes of refining.
The charcoal formerly used in this manufacture was prepared in the
usual way of charring wood, piles being formed of it and covered with
sods or fern, and suffered to burn with a slow smothering flame. This
method however cannot with any certainty be depended on to produce
charcoal of a uniformly good quality, and therefore a most essential
improvement has been adopted in this country, to which the present
superior excellence of American powder may be in a good measure
attributed, which is, that of enclosing the wood, cut into billets
about nine inches long, in iron cylinders placed horizontally, and
burning them gradually to a red heat, continuing the fire till every
thing volatile is driven off, and the wood is completely charred. But
as the pyroligneous acid, the volatile product of the wood heated
_per se_, is of use in manufacture, it is collected by pipes passing
out of the iron cylinder, and dipping into casks where the acid
liquor condenses. This acid is used in some parts of calico-printing,
chiefly as the basis of some of the iron liquors and mordants for
dark-coloured patterns. The wood before charring is barked. It is
generally either alder or willow, or dog-wood, but there does not
appear to be any certain ground for preferring one wood to another
provided it be fully charred.
The above three ingredients being prepared, they are first separately
ground to fine powder, then mixed in the proper proportions, after
which the mixture is fit for the important operation of thoroughly
incorporating the component parts in the mill. A powder mill is a
slight wooden building, with a boarded roof, so that in the event of
any moderate explosion, the roof will fly off without difficulty,
and the sudden expansion will thus be made in the least mischievous
direction. Stamping mills were formerly used here, which consisted
simply of a large wooden mortar, in which a very ponderous wooden
pestle was made to work, by the power of men, or horses, or water,
as convenience directed. These performed the business with very
great accuracy, but the danger from over-heating was found to be so
great, and the accidents attributable to this cause were so numerous,
that stamping mills have been mostly disused in large manufactures,
and the business is now generally performed by two stones placed
vertically, and running on a bed-stone or trough.
The mixed ingredients are put on this bed-stone in quantities not
exceeding 40 or 50 pounds at a time, and moistened with just so
much water, as will bring the mass in the grinding to a consistence
considerably stiffer than paste, in which it is found by experience
that the incorporation of the ingredients goes on with the most ease
and accuracy. These mills are worked either by water or horses.
The composition is usually worked for about seven or eight hours
before the mixture is thought to be sufficiently intimate, and even
this time is often found, by the inferior quality of the powder, to
be too little. The fine powder manufactured at Battle in Sussex, is
still however made in large mortars or stamping mills, in the old
way, with heavy lignum vitæ pestles. Only a very few pounds of the
materials are worked at a time.
The composition is then taken from the mills and sent to the
_corning-house_, to be corned or grained. This process is not
essential to the manufacture of perfect gunpowder, but is adopted on
account of the much greater convenience of using it in grains than
in fine dust. Here the stiff paste is first pressed into hard lumps,
which are put into circular sieves with parchment bottoms, perforated
with holes of different sizes, and fixed in a frame connected with
a horizontal wheel. Each of these sieves is also furnished with a
_runner_ or oblate spheroid of lignum vitæ, which being set in motion
by the action of the wheel, squeezes the paste through the holes of
the parchment bottom, forming grains of different sizes. The grains
are then sorted and separated from the dust by sieves of progressive
dimensions.
They are then _glazed_ or hardened, and the rough edges taken off,
by being put into casks, filling them somewhat more than half-full,
which are fixed to the axis of a water-wheel, and in thus rapidly
revolving, the grains are shaken against each other and rounded, at
the same time receiving a slight gloss or glazing. Much dust is also
separated by this process. The glazing is found to lessen the force
of the powder from a fifth to a fourth, but the powder keeps much
better when glazed, and is less liable to grow damp.
The powder being thus corned, dusted and glazed, is sent to the
stove-house and dried, a part of the process which requires the
greatest precautions to avoid explosion, which in this state would
be much more dangerous than before the intimate mixture of the
ingredients.
The stove-house is a square apartment, three sides of which are
furnished with shelves or cases, on proper supports, arranged round
the room, and the fourth contains a large cast-iron vessel called a
_gloom_, which projects into the room, and is strongly heated from
the outside, so that it is impossible that any of the fuel should
come in contact with the powder. For greater security against sparks
by accidental friction, the glooms are covered with sheet copper, and
are always cool when the powder is put in or taken out of the room.
Here the grains are thoroughly dried, losing in the process all that
remains of the water added to the mixture in the mill, to bring it to
a working stiffness. This Mr. Coleman finds to be from three to five
parts in 100 of the composition. The powder when dry is then complete.
The government powder for ordnance of all kinds as well as for
small arms, is generally made at one time, and always of the same
composition; the difference being only in the size of the grains as
separated by the respective sieves.
A method of drying powder by means of steam-pipes running round
and crossing the apartment has been tried with success: by it
all possibility of an accident from over-heating is prevented.
The temperature of the room when heated in the common way by a
gloom-stove is always regulated by a thermometer hung in the door of
the stoves.
The strength of the powder is sometimes injured by being dried too
hastily and at too great a heat, for in this case some of the sulphur
sublimes out (which it will do copiously at a less heat than will
inflame the powder) and the intimate mixture of the ingredients is
again destroyed. Besides if dried too hastily, the surface of the
grain hardens leaving the inner part still damp.
Mr. Coleman deduces from experiment the following inferences, namely:
that the ingredients of gunpowder only pulverized and mixed have but
a very small explosive force: that gunpowder granulated after having
been only a short time on the mill, has acquired only a very small
portion of its strength, so that its perfection absolutely depends
on very long-continued and accurate mixture and incorporation of
the ingredients: that the strength of gunpowder does not depend on
granulation, the dust that separates during this process being as
strong as the clean grains: that powder undried, is weaker in every
step of the manufacture than when dried: and lastly, that charcoal
made in iron cylinders in the way already mentioned, makes much
stronger powder than common charcoal. This last circumstance is of so
much consequence, and is so fully confirmed by experience, that the
charges of powder now used for cannon of all kinds have been reduced
one-third in quantity, when this kind of powder is employed.
In barrelling powder, particular care must be taken to avoid
moisture, and this business is also generally reserved for dry
weather.
When powder is only a little damp, it may be restored to its former
goodness merely by stoving; but if it has been thoroughly wetted,
the nitre (the only one of the ingredients soluble in water)
separates more or less from the sulphur and charcoal, and by again
crystallizing, cakes together the powder in whitish masses, which
are a loose aggregate of grains covered on the surface with minute
efflorescences of nitre. In this case the spoiled powder is put into
warm water merely to extract the nitre, and the other two ingredients
are separated by straining and thrown away.
The specific gravity of gunpowder is estimated by Count Rumford to be
about 1.868.
The strength and goodness of powder is judged of in several ways;
namely, by the colour and feel, by the flame when a small pinch
is fired, and by measuring the actual projectile force by the
_eprouvette_, and by the distance to which a given weight will
project a ball of given dimensions under circumstances in all cases
exactly similar.
When powder rubbed between the fingers easily breaks down into an
impalpable dust, it is a mark of containing too much charcoal, and
the same if it readily soils white paper when gently drawn over it.
The colour should not be absolutely black, but is preferred to be
more of a dark blue with a little cast of red. The trial by firing is
thus managed; lay two or three small heaps of about a dram each on
clean writing paper, about three or four inches asunder, and fire one
of them by a red-hot iron wire: if the flame ascends quickly with a
good report, sending up a ring of white smoke, leaving the paper free
from white specks and not burnt into holes, and if no sparks fly off
from it, setting fire to the contiguous heaps, the powder is judged
to be very good, but if otherwise, either the ingredients are badly
mixed, or impure.
Gunpowder mixed with powdered glass, and struck with a hammer is said
to explode.
An advertisement appeared in the public papers some time in 1813
or 14, signed T. Ewel, addressed to powder manufacturers, by which
it appears, in the words of the advertisement, that "he obtained
from the United States a patent right for three very simple and
important improvements in the manufacture of gunpowder, which do
most truly diminish more than one half the risk, the waste, and the
expense of the manufacture. They consist in boiling the ingredients
by steam, in incorporating them without the objection of barrels,
the danger of pounders, or the tediousness of stones running on the
edge: and in the granulation effected by a simple machine turning
by hand or water, and graining more in a day than twenty hands,
losing not a particle of dust, and making not half the quantity for
re-manufacture. The advantages of this mode have been so great that
he had to discharge half his workmen from his manufactory, as will
be readily accounted for by those accustomed to the tediousness and
loss from graining, particularly the press powder by the sifter and
rollers, &c."
We have not seen the plan in operation, and, therefore, can say
nothing respecting it; but it would appear, from the description,
that the process was conducted altogether by steam. It is true, that
the use of steam is no new application, nor was it then, as it had
been used in Europe for heating of dye kettles, in soap boiling,
distilling, for warming apartments, and many other purposes. The
application to that particular use, that of the manufacture of
gunpowder, may be original as far as we know, notwithstanding steam
has been applied by means of pipes, &c. as is used at present in
some manufactories, for the drying of gunpowder. Professor, now
president Cooper, of Columbia College, S. C. (_Emporium of Arts and
Sciences_ vol. ii, p. 317) in making some observations respecting
that publication, believes, that the application of steam to the
manufacture of gunpowder to be practicable, and in reference to the
advertisement, also a real improvement; and speaking of steam for
that purpose adds, "whether it be adopted in England or not, or
whether among the numerous patents granted for the application of
steam to the arts and manufactures of that country, I know not."
On a general principle of heating apartments by steam, we may
remark, that one _cubic foot_ of boiler will heat about _two
thousand feet_ of space, in a cotton mill, whose average heat is
from 70° to 80° Fahr. One square foot of surface of steam pipe, is
adequate to the warming of two hundred cubic feet of space. Cast
iron pipes are preferable to all others for the diffusion of heat.
For drying muslins and calicoes, large cylinders are employed, and
the temperature of the apartment is from 100° to 130°. Dr. Black
observes that steam is the most effectual carrier of heat that can
be conceived, and will deposite it only on such bodies as are colder
than boiling water.
Dr. Ure (_Researches on Heat_) has given a new table of the latent
heat of vapours, by which it appears that the vapour of water, at its
boiling point, contains 1000 degrees, while that of alcohol of the
specific gravity, .825 contains 457°, and ether, whose boiling point
is 112°, only 312.9. We see then not only by the recent experiments
of Ure, but also those of Dr. Black, Lavoisier and Laplace, Count
Rumford, Mr. Watt and some others, that water is the best carrier
of heat, using the expression of Dr. Black, and hence is admirably
calculated for the warming of apartments and other purposes.
Steam may be applied for the heating of water or other fluids, either
for baths or manufactures, and consequently for the saltpetre and
sulphur refineries, attached to a gunpowder establishment, either by
plunging the steam pipe with an open end into the water cistern, if
it be for the heating of water, or by diffusing it around the liquid
in the interval between the wooden vessel and an interior metallic
case. This last mode is applicable to all purposes.
A gallon of water in the form of steam will heat 6 gallons at 50° up
to the boiling point, or 162 degrees; or one gallon will be adequate
to heat 18 gallons of the latter up to 100 degrees, making an
allowance for waste in the conducting pipe.
Mr. Woolf (_Monthly Magazine_ vol. xxxii, p. 253) has taken out a
patent for a steam apparatus for various purposes, among which that
for the drying of gunpowder is specified. This patent is considered
under three heads; _viz._ the construction of the boilers, which are
cylindrical vessels properly connected together, and so disposed as
to constitute a strong and fit receptacle for water, or any other
fluid, intended to be converted into steam, and also to present an
extensive portion of convex surface to the current of flame, or
heated air or vapour from a fire. Secondly, of other cylindrical
receptacles placed above these cylinders, and properly connected
with them, for the purpose of containing water and steam, and for
its reception, transmission, &c. Thirdly, of a furnace so adapted to
the cylindrical parts just mentioned, as to communicate heat with
facility and economy. By means of this invention, he states, that any
desired temperature, necessary for the drying of gunpowder, may be
produced where the powder is to be dried, without the necessity of
having fire in, or so near the place as to endanger its safety; for
by employing steam only, conveyed through pipes, and properly applied
and directed, without allowing any of it to escape into the room or
apartment where the powder is, any competent workman can produce a
heat equal to that found necessary for drying gunpowder, or much
higher if required. The heat may be regulated, to effect the purpose,
without producing the sublimation of the sulphur, which has sometimes
taken place.
Among the numerous patents of the late D. Pettibone are some for
ovens, both fixed and portable, for the drying of gunpowder. Speaking
of the use of heated air (_Description of the Improvements of the
Rarefying air-stove_, p. 19) he observes, that powder makers would
derive a very great advantage by using rarefied air for drying their
gunpowder.
Mr. Ingenhouz (_Nouvelles experiences et observations sur divers
objects de physique_) attributed the effect of gunpowder to the
simultaneous disengagement of dephlogisticated air from the nitre,
and inflammable air from the charcoal at the moment of ignition. He
followed the calculation of Bernouilli with respect to the quantity
of gas generated, _viz_: that one cubic inch of gunpowder at the
moment of inflammation, calculating at the same time its expansion,
occupies not less than 2276 cubic inches.
That the effective force of gunpowder depends on the generation and
expansion of sundry gaseous fluids, is evident, from the chemical
action which takes place in the combustion. At a _red_ heat gunpowder
explodes. This ensues even in a vacuum; a fact at once conclusive,
that, while it possesses the inflammable principle, it has also the
supporter of combustion. It is to be observed that the particle of
powder which is struck by the spark, is instantaneously heated to the
temperature of ignition, and is thereby decomposed; and the affinity
existing between its oxygen or the oxygen of the nitric acid, and the
charcoal and sulphur produces the principal part of the gases. The
caloric thus evolved, inflames successively, though with rapidity,
the remaining mass. The expansive force of powder, is therefore
attributed to the sudden production of carbonic acid gas, sulphurous
acid and nitrogen gas, with the water which is instantaneously
converted into steam; all of which are greatly augmented by the
quantity of caloric liberated.
The combustion, therefore, is owing to the action of the charcoal
and sulphur on the nitre; and the decomposition is the effect of
the union of the charcoal with a part of the oxygen of the nitric
acid, with which it forms carbonic acid, and also with the sulphur
producing sulphurous acid gas. It is asserted, that sulphuretted
hydrogen gas is also produced; if so, there must be a sulphuret
formed, which decomposes a part of the water. After combustion, what
remains is carbonate of potassa, sulphate of potassa, and a small
proportion of sulphuret of potassa and unconsumed charcoal. Good
powder, however, should leave no very sensible residue when inflamed:
this is one of the proofs recommended. Thenard observes, (_Traité
de Chimie_, ii, p. 498,) that the products of the combustion of
gunpowder are numerous; some gaseous, and some solid. The gaseous
products are carbonic acid, deutoxide of azote (nitrous gas) and
azotic gas, besides the vapour of water; and the solid products are
sub-carbonate of potassa, sulphate of potassa, and sulphuret of
potassa.
M. Proust considers, that nitrite of potassa, prussiate of potassa,
charcoal, sulphuretted hydrogen gas, carburetted hydrogen gas,
nitrous gas, and carbonic oxide gas may be generated or result, as
the products of the combustion, when the materials have not been
properly mixed. Our object in all cases should be to render the
materials pure, and the proportions so accurate, as to produce the
greatest possible effect, which, of course, must depend on the
formation and the consequent expansion of the gases. The effect of
fired gunpowder is owing in a great degree to the generation of
carbonic acid gas; for while the charcoal acts primarily in the
combustion, by taking a greater part of the oxygen from the nitric
acid of the nitre, with which we have said it produces carbonic
acid; the sulphur has a secondary influence, by forming sulphurous
acid gas, although it renders the combustion more rapid, and in this
respect enables the charcoal to act at once on the nitric acid of the
saltpetre.
We learn then, that in gunpowder, the quantity of charcoal should
be such as to effect the decomposition; and, that while the sulphur
has a secondary effect, in the formation of sulphurous acid gas,
it promotes, if so we may term it, the _rapid_ combustion, and
consequent action of the charcoal.
MM. Bottée and Riffault (_Traité de l'art de Fabriqué la poudre à
canon, p. 197_,) after making some observations on the constitution
of powder, and the action which takes place when it is burnt,
with the aeriform products that result, give some remarks on the
proportion of charcoal necessary to decompose a given quantity of
nitric acid; and conclude generally, that in the production of
carbonic acid gas, the principal gas which is formed, while the
nitric acid is decomposed, and gives up its oxygen to the carbon,
the azote is liberated in the state of gas, and at the same time
caloric is evolved. They observe then, that the ancient formula
for the manufacture of gunpowder, as used in France, consists of
the following proportions, _viz_: 0.750 saltpetre, 0.125 charcoal,
and 0.125 sulphur, which agrees with modern experiments, although
chemistry at that period was in its infancy. M. Pelletier, a member
of the National Institute, and M. Riffault made several experiments
at Essonne, on different proportions of nitre, charcoal, and
sulphur in the fabrication of powder. It is unnecessary to state
the different proportions, made use of, or the experiments on the
strength of the powder made with the eprouvette. They observe,
however, that powder made in the following proportions, was more
satisfactory, _viz._ 0.76 saltpetre, 0.15 charcoal, 0.09 sulphur, and
0.76 saltpetre, 0.14 charcoal, and 0.10 sulphur.
Before we give the gaseous products, according to these gentlemen,
it will be necessary to observe, that the quantity of nitric acid
in nitrate of potassa, is 48.62 in the hundred, and according to
Gay-Lussac, nitric acid is composed in volume of 250 oxygen and 100
azote, or in weight of 69.488 oxygen, and 30.512 azote.
Using the French _gramme_ in the present instance, it appears that
75 grammes of nitrate of potassa, the proportion of this salt which
enters into 100 grammes of gunpowder for war, contains 36.47 grammes
of nitric acid; and that this quantity of acid is formed of 25.34
grammes of oxygen, and 11.13 grammes of azote. That quantity of
oxygen (25.34) is disengaged from its combination with azote in the
nitric acid, at the instant of the inflammation of the powder by the
charcoal, forming carbonic acid; the constituents of which, according
to the proportions established by Gay-Lussac and others, must be in
the ratio of 27.376 of carbon and 72.624 of oxygen. If 25.34 grammes
of oxygen exist in 75 grammes of nitrate of potassa, the proportion
usually admitted, then it will require 9.55 grammes of carbon to
saturate it, so as to produce carbonic acid. It is necessary to
consider, that this is independent of any foreign earthy or saline
matter or moisture which may exist.
With respect to the presence of hydrogen in charcoal, the
observations of Dr. Priestley, Cruikshanks, Kirwan, Berthollet,
Gay-Lussac, Thenard, Vauquelin, Lowitz and some others, are
conclusive on that head. Lavoisier made the quantity of hydrogen in
charcoal upon an average, to be 0.125 of its weight. See _Memoirs de
la Société d'Arcueil_, tome ii, p. 343, and the _Statique Chimique_,
tome ii, pages 44 and 45, and also _charcoal_ in a preceding section.
It is said, that by employing more charcoal than is necessary to
decompose the nitric acid of the nitre, the excess passes off, not
as carbonic acid, but carbonic oxide, or gaseous oxide of carbon,
which is necessarily inflamed, and finally forms carbonic acid, as
one of the products with the carbonic acid originally formed. But the
carbonic oxide, to be changed into carbonic acid, requires in fact
the oxygen of the atmosphere.
If 34.89 grammes of carbonic acid result from the combustion of
9.55 grammes of carbon, it must unite with a quantity of oxygen,
as before expressed, and according to the temperature, be more or
less expanded. The 11.13 grammes of azote thus disengaged from its
combination with oxygen, in the nitric acid, remains, of course, in
the gaseous state, and is also expanded by caloric. The quantity of
the latter is stated by Lavoisier, to be 430 degrees, using a scale
of 80 parts; and according to more recent experiments, it is fixed
at 600 degrees of the centigrade thermometer. The experiments of
Gay-Lussac are more recent, in which he has given the dilatation
of the gases, and the quantity of free caloric evolved, which
corresponds with the last data. We have not room to insert his
remarks.
The use of sulphur with the charcoal, in the fabrication of powder,
Bottée and Riffault state to be, (page 204) that it inflames more
rapidly than charcoal, and at a lower temperature, which accelerates
the combustion of the charcoal, and consequently the detonation of
the powder. The presence of the sulphur augments the volume of gas,
by producing sulphurous acid gas. The proportion of sulphur in the
powder for war, is, 0.125, for musket powder, 0.10, and for mining
powder, 0.20, according to the same gentlemen.
M. Fourcroy (_Système des Connaissances Chimiques_, tome iii, p.
122.) among other products of the combustion of powder, mentions
ammonia. If ammoniacal gas be formed, the hydrogen must proceed from
decomposed water, and the azote from the nitric acid. Prussine,
cyanogen, or carburet of nitrogen, the radical of prussic acid, may
also be generated by the union of carbon and nitrogen or azote, in
the same manner. We know that cyanogen may exist in the form of gas;
but as it is inflammable, burning with a bluish flame mixed with
purple, we may infer, nevertheless, that, if generated, it must
undergo decomposition by the process of combustion. Although I know
of no experiments on this subject, either by Gay-Lussac, Vauquelin or
Davy, all of whom have investigated the properties of this compound
of carbon and azote, which Dr. Ure has called _prussine_; yet it
would appear, that during its combustion, the carbon is changed into
carbonic acid, and whether the azote be also combined with oxygen,
or merely set at liberty, is altogether uncertain. Many difficulties
present themselves to a complete and satisfactory set of experiments
on the gaseous products of fired gunpowder.
With respect to the granulation of powder, we may observe, that
although some writers consider that granulated powder is _stronger_
than the fine powder, yet others are of opinion, that its strength is
not increased by granulation. Grained powder is more fit for use; but
the graining of it prevents the whole of the powder from taking fire
instantaneously. Gunpowder, although prepared in the best manner,
is not wholly consumed by inflammation. However remarkable it may
appear, yet nevertheless it is true, that a considerable portion
of gunpowder fired in a confined space is thrown out without being
kindled. That gunpowder passes through a volume of fire without being
consumed, may seem incredible, yet the fact may be proved by firing
with a musket upon snow, or upon a paper screen.
M. Morveau communicated to the Institute some experiments, which may
be seen in the _Archives des Découvertes_, i, p. 269, relative to the
time necessary for the inflammation of a given mass of gunpowder, &c.
He infers that large grain powder inflames more readily than the fine
grain.
Since during the combustion of powder, gaseous bodies more or less
considerable are generated, it follows that the full force of fired
gunpowder must depend on the maximum of the quantity of those gases;
and the powder is more strong as it is susceptible of forming more
gas in a given time. Besides the purity and the proper proportion
of the materials, the gunpowder, to produce the greatest possible
effect, should not only be intimately mixed, but dried perfectly and
with care.
It is a fact which is well known, that a musket, fowling piece, &c.
are very apt to burst, if the wadding is not rammed down close to the
powder. Hence it is obvious, that in loading a screw barrel pistol,
care should be taken that the cavity for the powder be entirely
filled with it, so as to leave no space between the powder and the
ball.
Experience has shown, that if a shell is only half or two-thirds
filled with gunpowder, it breaks into a great number of pieces, and
on the contrary, if completely filled, it separates only into two or
three pieces, which are thrown to a very great distance.
It is also found that the same principle, of leaving a space for
air, is applied with success in blasting rocks, and splitting trunks
of trees. If the trunk of a tree is charged with gunpowder, and
the wadding is rammed down very hard upon the powder, in that case
(unless the quantity of powder is great,) the wadding is only driven
out, and the tree remains entire; but if, instead of ramming the
wad close to the powder, a certain space is left between them, the
effects of the powder are then such as to tear the tree asunder.
Addison (_Travels through Italy and Swisserland_) speaking of the
celebrated Grotto Del Cani, which contains carbonic acid gas, and
on that account extinguishes flame, and is fatal to animal life,
observes, that he laid a train of gunpowder in the channel of a reed,
and placed it at the bottom of the grotto, and on inflaming it, that
it burnt entirely away, although the carbonic acid gas in the same
spot would immediately extinguish a lighted taper, snuff and all;
for, he remarks, fire is as soon extinguished in it as in water. If
gunpowder did not contain within itself that which was necessary to
produce combustion, how are we to account for its combustion in an
atmosphere of carbonic acid gas, or in vacuo?
Whether gunpowder be fired in a vacuum or in air, a permanently
elastic fluid is generated, the elasticity or pressure of which is,
_cæteris paribus_, directly as its density.
Gregory, (_Treatise on Mechanics, &c._ ii, p. 56) has given a summary
of the results of the experiments of Mr. Robins, which we insert
verbatim. "To determine the elasticity and quantity of this fluid
(the elastic) produced from the explosion of a given quantity of
gunpowder, Mr. Robins premises, that the elasticity increases by
heat, and diminishes by cold, in the same manner as that of the air;
and that the density of this fluid, and consequently its weight, is
the same with an equal bulk of air, having the same elasticity at the
same temperature. From these principles, and from the experiments by
which they are established (for a detail of which we must refer to
the book itself,) he concludes that the fluid produced by the firing
of gunpowder, is nearly 3/10ths of the weight of the generating
powder itself; and that the volume or bulk of this air or fluid, when
expanded to the rarity of common atmospheric air, is about 244 times
the bulk of the said generating powder. Count Salace in his _Miscel.
Phil. Math. Soc. Priv._ Taurin, p. 125, makes the proportion as 222
to 1; which he says agrees with the computation of Messrs. Hawkesbe
Amontons, and Belidor. Hence it would follow that any quantity of
powder fired in any confined space, which it adequately fills, exerts
at the instant of its explosion against the sides of the vessel
containing it, and the bodies it impels before it, a force at least
244 times greater than the elasticity of common air, or, which is the
same thing, than the pressure of the atmosphere; and this without
considering the great addition arising from the violent degree of
heat, with which it is endued at that time; the quantity of which
augmentation is the next head of Robins's inquiry.
He determines that the elasticity of air is augmented in a proportion
somewhat greater than that of 4 to 1, when heated to the extremest
heat of red-hot iron; and supposing that the flame of fired gunpowder
is not of a less degree of heat, increasing the former number a
little more than four times, makes nearly 1000; which shows that the
elasticity of flame, at the moment of explosion, is about 1000 times
stronger than the elasticity of common air, or than the pressure of
the atmosphere. But, from the height of the barometer, it is known
that the pressure of the atmosphere upon every square inch is on a
medium of 14-3/4ths, and therefore 1000 times this, or 14750 lbs.
is the force of pressure of inflamed gunpowder, at the moment of
explosion, upon a square inch, which is very nearly equivalent to six
tons and a half. This great force, however, diminishes as the fluid
dilates itself, and in that proportion; viz. in proportion to the
space it occupies, it being only half the strength, when it occupies
a double space, one-third the strength, when a triple space, and so
on. Mr. Robins further supposed the degree of heat above mentioned to
be a kind of medium heat; but that in the case of large quantities of
powder the heat will be higher, and in very small quantities lower;
and that therefore in the former case the force will be somewhat
more, and the latter somewhat less, than 1000 times the force of the
atmosphere.
He further found, that the strength of powder is the same in all
variations in the density of the atmosphere: but that the moisture of
the air has a great effect upon it; for the same quantity which in a
dry season would discharge a bullet with the velocity of 1700 feet in
one second, will not in damp weather give it a velocity of more than
12 or 1300 feet in a second, or even less, if the powder be bad, or
negligently kept. _Robins's Tracts_ vol. i, p. 101, &c. Further, as
there is a certain quantity of water, which, when mixed with powder,
will prevent its firing at all, it cannot be doubted but every degree
of moisture must abate the violence of the explosion; and hence the
effects of damp powder are not difficult to account for.
The velocity of expansion of the flame of gunpowder, when fired in a
piece of artillery, without either bullet or other body before it, is
prodigiously great, viz. 7000 feet per second. But Mr. Bernoulli and
Mr. Euler think it is still much greater.
Dr. Hutton, after applying some requisite corrections to Mr. Robins's
numbers, and after remarking that the powder does not all inflame at
once, as well as that about 7/10ths of it consist of gross matter
not convertible into an elastic fluid, gives v = 125 [sqrt] ((n ·
q)/(16 + q) × log. of b/a) for the initial velocity of any ball of
given weight and magnitude, and n = ((p + w)/3180 ad^2)v^2 ÷ log. b/a
for the value of the initial force n of the powder in atmospheric
pressures: when a = length of the bore occupied by this charge,
b = whole length of the bore, d = diameter of the ball, w = its
weight, 2 p = weight of the powder, q = a/d. In his experiments and
results, he found n to vary between 1700 and 2300, and the velocity
of the flame to vary between 3000 and 4732; specifying, however, the
modification in his computations, which would give more than 7000
feet per second for that velocity. Taking 2200 for an average value
of n, and substituting 47 for its square root in the above formula
for v, it becomes v = 5875 [sqrt] (q/(16 + q) × log. of b/a) for the
velocity of the ball, a theorem which agrees remarkably well with
the Doctor's numerous and valuable experiments. (Tracts, vol. iii, p.
290, 315.)
In a French work entitled, "_Le Mouvement Igné_ considéré
principalement dans la charge d'une pièce d'artillerie," published
in 1809, there are advanced, among other notions which we apprehend
few philosophers will be inclined to adopt, some which may demand
and deserve a careful consideration. The author of this work
observes, that if a fluid draws its force partly from a gaseous
or aeriform matter, and partly from the action of caloric, which
rarefies that aeriform matter; then its density in proportion to its
dilatation, will follow the inverse ratios of the squares of the
spaces described. He then investigates two classes of formulæ: the
first appertains to fluids which possess simply the fluid or aeriform
elasticity, which are free from all heat exceeding the temperature
of the atmosphere. Whether there be one or many gaseous substances
signifies not, provided their temperature agrees with that of the
atmosphere; for when these dilate they conform to the inverse of
the spaces described. The second relate to those which derive their
elasticity as well from the aeriform fluids, as from the matter of
heat which pervades them, and which are denominated _fluids of mixed
elasticity_, to distinguish them from those of simple or purely
_aeriform elasticity_. These fluids, in dilating, conform to the
inverse ratio of the _squares_ of the spaces described. Thus the
celerity of action of mixed elastic fluids, is to that of simple
elastic fluids as S^2 to S; whence it follows that mixed elastic
fluids are more prompt and energetic in their action than others; and
hence also is inferred why the fluid produced by the combustion of
gunpowder, is more impetuous and more terrible in its operation than
atmospheric air, however compressed it may be. The force exerted by
the caloric to dissolve a quantity of powder, is regarded as equal
to that possessed by the fluid which results from that dissolution,
and is named the _force of dissolution_ of powder by fire: and the
_surface of least resistance_ is that (as of the ball,) which yields
to the action of the fluid. The gunpowder subjected to experiment by
this author, was of seven different qualities, varying from 1000,
the density of water, down to 946, the density of powder used by
sportsmen. It was found by theory, and confirmed by experiment, that
the real velocity with which the elastic fluid, considered under the
volume of the powder, and penetrated by a degree of heat capable of
quadrupling the volume, would expand, when it had only the resistance
of the atmosphere to surmount, is 2546.49 feet, that is, about 2734.4
feet English.
Comparing the several forces which were calculated for the same
quantity of powder, in three different circumstances:
1. When the fluid has only to surmount the atmospheric pressure,
it has a force of dissolution which is proper to it, and which in
a charge of 8 lbs. of powder (the specific gravity 944.72, for a
24 pounder,) acts upon the surface of the least resistance with an
energy equivalent to 9747.8074 lbs.
2. The fluid retarded in its expansion by a surface of least
resistance, whose tenacity (occasioned by the compactness and
pressure of the wadding, &c.) is t = 31, acquires by its elasticity
of force = 52839.1463 lbs. at the instant when that surface yields to
its action.
3. If the tenacity t = 298 lbs., the force of the fluid at the moment
when the resisting surface yields to it, will be equivalent to
417371.4275 lbs. If each of these forces be divided by the surface
of least resistance, the quotient will indicate the equation of each
filament, namely, 1st. That of the force of dissolution = 173.63
grains; 2d. when t = 31 lbs. that of elasticity = 923.26 grains; 3d.
when t = 298 lbs. force elastic equal to 7433.99 grains.
Dividing again these latter values by the length of the charges, we
shall have for the mean force of each elementary fluid particle,
1. Force of dissolution, 0.14205 grains.
2. When t = 31 lbs. the force elastic = 0.75540 grains.
3. When t = 298 lbs. the force elastic = 6.08174 grains.
It appears, however, that equal charges of powder of the same quality
employed in the same piece, produce very different velocities; the
more considerable being the resistance to the expansion of the fluid,
the less the velocity becomes. Thus, it is found, when t = 31 lbs.
the velocity of the ball when expelled at the mouth of the piece, is
1563.6 feet: when t = 298 lbs. v = 1350.9 feet.
The following table will exhibit in one view the velocities with
which a 24 lb. ball issues from the mouth of a gun, when propelled
with the several charges expressed in the first column.
1st. According to the theory developed in the volume, from which we
have made these extracts.
2d. According to the experiments of M. Lombard, at Auxerre, on guns
for land service.
3d. According to the experiments of M. Teixiere de Norbec, at Toulon,
on guns for sea service.
4th and 5thly. According to the determination of Mr. Robins and Dr.
Hutton.
+-------+---------------+--------+-----------------+-----------------+
| | Velocity from | Mean | Velocity from | VELOCITIES. |
|Charges| Theory |velocity| experiment. | |
| of +-------+-------+ from +- ------+--------+--------+--------+
|powder.| When | When | Theory.| | | | |
| | t=31. | t=298.| |Lombard.|Norbec. |Robins. |Hutton. |
+-------+------ +-------+--------+--------+--------+--------+--------+
| 1 lb. | 622 | 524 | 573 | 575 | 570 | 640 | 500 |
| 2½ | 980 | 836 | 908 | 906 | 940 | 750 | 730 |
| 3 | 1072 | 918 | 995 | 989 | 1020 | 969 | 830 |
| 4 | 1233 | 1057 | 1145 | 1132 | 1245 | 1069 | 940 |
| 6 | 1407 | 1216 | 1312 | 1320 | 1340 | 1215 | 1164 |
| 8 | 1564 | 1351 | 1457 | 1425 | 1560 | 1319 | 1348 |
|10 | 1581 | 1370 | 1476 | 1475 | | | 1500 |
|12 | 1631 | 1421 | 1526 | 1530 | | | 1600 |
+-------+-------+-------+--------+--------+--------+--------+--------+
It is the prodigious celerity of expansion of the flame of fired
gunpowder, which is its peculiar excellence, and the circumstance in
which it so eminently surpasses all other inventions, either ancient
or modern; for as to the momentum of these projectiles only, many of
the warlike machines of the ancients produced this in a degree far
surpassing that of our heaviest cannon, shot or shells; but the great
celerity given to them cannot be approached with facility by any
other means than the explosion of powder."
Dr. Hutton, in conjunction with several able officers of the
artillery and other gentlemen, made an extensive course of
experiments at Woolwich, at the expense of the British government,
by the direction of the then master-general of the ordnance, (the
late duke of Richmond,) in the years 1783, 1784, and 1785, which
demonstrated the following facts:
1. That the velocity continually increases as the gun is longer,
though the increase in velocity is but very small in respect of
the increase in length; the velocities being in a ratio somewhat
less than that of the square roots of the length of the bores, but
somewhat greater than the cube roots of the same, and nearly indeed
in the middle ratio between the two.
2. That the charge being the same, very little is gained in the
range of a gun, by a great increase of its length; since the range
or amplitude is nearly as the fifth root of the length of the bore,
and gives only about a seventh part more range with a gun of double
length.
3. That with the same gun and elevation, the time of the ball's
flight is nearly as the range.
4. That no sensible difference is produced in the range or velocity,
by varying the weight of the gun, by the use of wads, by different
degrees of ramming, or by firing the charge of powder in different
parts of it.
5. That a great difference, however, in the velocity, is occasioned
by a small variation in the windage; so much so, indeed, that with
the usual windage of one-twentieth of the caliber, no less than
between one-third and one-fourth of the whole charge of the powder
escapes and is entirely lost; and that as the windage is often
greater, one-half the powder is unnecessarily lost.
6. That the resisting force of wood to balls fired into it, is not
constant, and that the depths penetrated by different velocities, or
charges, are not as the charges themselves, or, which comes to the
same thing, as the squares of the velocities.
7. That balls are greatly deflected from the direction they are
projected in, sometimes, indeed, so much as 300 or 400 yards in a
range of a mile, or almost a fourth part of the whole range, which is
nearly a deflection of an angle of 15 degrees.
The observations of Glenie, (_History of Gunnery_, 1776,) show the
theory of projectiles in vacuo by plain geometry, or by means of the
square and rhombus; with a method of reducing projections on inclined
planes, whether elevated or depressed below the horizontal plane, to
those which are made on the horizon.
This author, in his treatise, after stating in page 48, the two
following positions of Mr. Robins, namely, "that till the velocity of
the projectile surpasses that of 118 feet in a second; the resistance
of the air may be estimated to be in the duplicate of the velocity;"
that "if the velocity be greater than that of 11 or 1200 feet in a
second, the absolute quantity of the resistance will be nearly three
times as great as it should be by a comparison with the smaller
velocities;" says, that he is certain from some experiments, which he
and two other gentlemen tried with a rifle piece properly fitted for
experimental purposes, that the resistance of the air to a velocity
somewhat less than that mentioned in the first of these proportions,
is considerably greater than in the duplicate ratio of the velocity;
and that to a celerity somewhat greater than that stated in the
second, the resistance is less than that which is treble the
resistance of the same ratio. He observes, also, that some of Mr.
Robins's own experiments come to this conclusion; since to a velocity
no quicker than 200 feet in a second, he found the resistance to
be somewhat greater than in that ratio, and remarks, therefore,
that "after ascertaining the velocities of the bullets with as much
accuracy as possible, I instituted a calculus from principles which
had been laying by me for some time before, and found the resistance
to approach nearer to that, which exceeds the resistance in the
duplicate ratio of the velocity, by that which is the ratio of the
velocity, than to that, which is only in the duplicate ratio."
The experiments of Mr. Dalton, confirm the premises of Mr. Robins,
that the elasticity of the gases produced from a given quantity
of powder, is equally increased by heat and diminished by cold as
that of atmospheric air. Hence, as we before remarked, and from
direct experiments, he concludes that the elastic fluid produced by
the firing of gunpowder, is nearly three-tenths of the weight of
the powder itself, which, expanded to the rarity of common air, is
about 244 greater than the elasticity of common air, or in other
words, than the pressure of the atmosphere. To this, however, must
be superadded the increase of expansive power produced by the heat
generated, which is very intense. The mere conversion of confined
powder into elastic vapour, would exert against the sides of the
containing vessel, an expansive force 244 times greater than the
elasticity of common air, or, in other words, than the pressure of
the atmosphere. If the heat, for the expansion of the gases, should
be equal to that of red-hot iron, this would increase the expansion
of common air, (and also of all gases) about four times, which in
the present instance would be as we stated in the preceding pages,
244 to nearly 1000; so that in a general way it may be assumed, that
the expansive force of closely confined powder at the instant of
firing, is 1000 times greater than the pressure of common air; and
as this latter is known to press with the weight of 14-3/4 pounds on
every square inch, the force of explosion of gunpowder is 1000 times
this, or 14750 lbs. or about six tons and a half upon every square
inch. This enormous force diminishes in proportion as the elastic
fluid dilates, being only half the strength when it occupies a double
space, one-third of the strength when in a triple space, and so on.
There is one more fact worthy of notice, that Mr. Robins found the
strength of powder to be the same in all variations of the density
of the atmosphere, but not so in every state of moisture, being much
impaired by a damp air, or with powder damped by careless keeping,
or any other cause; so that the same powder which will discharge a
bullet at the rate of 1700 feet in a second in dry air, will only
propel it about 1200 feet when the air is fully moist, and a similar
difference was observed between dry and moist powder. The sum of
these remarks, with the necessary illustrations, may be found in the
extract we have given from Gregory's Mechanics.
Before we mention the different modes of proving powder, we will
offer some remarks respecting the use of sulphur in gunpowder. The
conclusions on this head are drawn from the experiments made at
Essonne, near Paris.
The sulphur is not (properly speaking) a necessary ingredient
in gunpowder, since nitre and charcoal alone, well mixed, will
explode; but the use of the sulphur seems to be to diffuse the
fire instantaneously through the whole mass of powder. But, if the
following experiments are correct, it should seem that the advantage
gained by using sulphur in increasing the force of explosion only
applies to small charges; but in quantities of a few ounces, the
explosive, or at least the _projecting_ force of powder without
sulphur, is full as great as with sulphur.
The following are a few out of many trials made at the Royal
Manufactory at Essonne, near Paris, in the year 1756, to determine
the best proportions of all the ingredients. Of powder made with
nitre and charcoal alone, 16 of nitre and 4 of charcoal was the
strongest, and gave a power of 9 in the eprouvette. With all three
ingredients, 16 of nitre, 4 of charcoal, and 1 of sulphur, raised the
eprouvette to 15, and both a less and a greater quantity of sulphur
produced a smaller effect. Then diminishing the charcoal, a powder
of 16 of nitre, 3 of charcoal, and 1 of sulphur gave a power of 17
in the eprouvette, which was the highest produced by any mixture.
This last was also tried in the mortar-eprouvette against the common
proof powder, and was found to maintain a small superiority. The
powder made without sulphur in the proportions above indicated was
also tried in the mortar-eprouvette, and with the following singular
result: when the charge was only two ounces it projected a sixty
pound copper ball 213 feet, and the strongest powder with sulphur
projected it 249 feet; but in a charge of three ounces, the former
projected the ball 475 feet and the latter only 472 feet; and on the
other hand the great inferiority of force in the smaller eprouvette
of the powder without sulphur has been just noticed.
It is a fact, known from time immemorial, that by the combustion of
bodies caloric is generated, or chemically speaking, is given out in
a free state; but the cause was not known until the anti-phlogistic
theory of chemistry was established, which abolished as untenable
the old doctrine of phlogiston; The quantity of caloric, which
passes from a latent to a free state in combustion, as combustion
is nothing more than the phenomena occasioned by this transition,
is variable; and depends therefore on the substances burnt, and the
nature of what is denominated the supporter of combustion.
The experiments of MM. Lavoisier and Laplace have shown the quantity
of caloric produced by the combustion of different substances by
the calorimeter, a table of which may be seen in Thenard. (_Traité
de Chimie_, &c. t. i, p. 81). From this table it appears, that
while a mixture of one pound of saltpetre with one pound of sulphur
liquefied, by its combustion, thirty-two pounds of ice, one pound
of hydrogen gas melted 313 lbs. phosphorus 100 lbs. and the same
quantity of charcoal 96.351 lbs.; and by the detonation of a mixture
of one pound of saltpetre with 0.3125 lbs. of charcoal (French
weight) melted only 12 lbs. of ice.
In the table of the elevation of temperature by the combustion of
different substances, the caloric being communicated to water,
(Thenard, _Traité de Chimie_, vol. i, p. 82), it appears, that by the
combustion of equal weights of hydrogen gas, phosphorus, charcoal,
and oak, the caloric produced was as follows:
Hydrogen 23,400°
Phosphorus 7,500
Charcoal 7,226
Oak wood 3,146
The reader may find some interesting calculations on this subject in
Biot's _Traité de Physique_, &c. tome iv, p. 704, and 716.
It appears also, that in the combustion of one pound of hydrogen
gas, six pounds of oxygen were consumed, and according to Crawford's
experiment the caloric given out melted 480 lbs. of ice. One pound of
phosphorus requires for combustion one and a half pounds of oxygen
gas; one pound of charcoal, 2.8; and one pound of sulphur, 1.36. See
Thomson's _System of Chemistry_, vol i, p. 133.
While noticing this subject we may remark, that in combustion heat
and light, according to the Lavoiserian doctrine, are given out from
the oxygen gas, while the oxygen unites with the combustible body:
which has since been modified by supposing, that while caloric is
evolved from the gas, the light is emitted from the burning body.
There are some facts contrary to the received theory of combustion;
that of _gunpowder_ furnishes one. We have also another instance in
the combustion of oil of turpentine by nitric acid.
Gunpowder will burn with great avidity in close vessels, or under
an exhausted receiver, and we know that the oxygen is already
combined with azote in the nitric acid of the nitrate of potassa,
and consequently not in a gaseous but a solid state; yet we also
know that a great quantity of caloric and light are emitted during
the combustion, and nearly all the products are gaseous. The other
anomaly is, that as combustion is produced by pouring nitric acid on
spirit of turpentine, the oxygen being already combined with azote,
caloric and light are evolved by the mixture of the two fluids,
from which it is inferred, that oxygen is capable of giving out
caloric and light, not only when liquid, but even after combustion.
In the instance of gunpowder, in order to explain the combustion
which takes place independently of atmospheric air, or any aeriform
supporter, "the caloric and light," in the opinion of Dr. Thomson,
(_Chemistry_, i, 128) "must be supposed to be emitted from a solid
body during its conversion into gas, which ought to require more
caloric and light for its existence in the gaseous state than the
solid itself contained."--Mr. Lavoisier (_Elements of Chemistry_, p.
157,) observes, that he and M. De la Place deflagrated a convenient
quantity of nitre and charcoal in an ice apparatus, and found that
12 lbs. of ice were melted by the deflagration of one pound of
nitre. After giving the proportions of acid and alkali in nitre,
and the quantity of oxygen and azote in the acid, he observes, that
during the deflagration, 145-1/3 grains of carbon have suffered
combustion along wit 3738.34 grains of oxygen; and as 12 lbs. of
ice were melted, one pound of oxygen burnt in the same manner would
have melted 29.5832 lbs. of ice. To which, if we add the quantity of
caloric retained by a pound of oxygen, after combining with carbon to
form carbonic acid gas, which was already ascertained to be capable
of melting 29.13844 lbs. of ice, we shall have for the total quantity
of caloric remaining in a pound of oxygen when combined with nitrous
gas in the nitric acid, 58.72164; which is the number of pounds of
ice, the caloric remaining in the oxygen in that state is capable of
melting. In the state of oxygen gas it contains at least 66.66667.
M. Lavoisier infers then, that the oxygen in combining with azote
to form nitric acid, only loses 7.94502, and that "this enormous
quantity of caloric, retained by oxygen in its combination into
nitric acid, explains the cause of the great disengagement of caloric
during the deflagration of nitre; or, more strictly speaking, upon
all occasions of the decomposition of nitric acid." This view of
the subject may enable us to explain the production of caloric, in
those cases of combustion which cannot be explained on the ordinary
principles; and, with regard to gunpowder, the accension of oil of
turpentine by nitric acid, and similar cases, we may conclude, as the
only rationale which seems applicable, that it is nothing more than
the transition of caloric from one state to another, from a latent
to a free state. Be this as it may, the combustion in such instances
furnishes an anomaly to the already established doctrine, of the
absorption of oxygen, or the base of the supporter, and the evolution
of caloric from the gas, and not from the combustible; or, in other
words, the change of caloric in the supporter from a combined to an
uncombined state.
The idea of _latent_ heat may be had from Dr. Black's own expression
(_Black's Lectures_ by Robinson:) "By this discovery," says
the doctor, "we now see heat susceptible of fixation--of being
accumulated in bodies, and, as it were, laid by till we have occasion
for it; and are as certain of getting the stored-up heat, as we are
certain of getting out of our drawers the things we laid up in them."
Murray's _System of Chemistry_, 2d edition, p. 398, and Watson's
_Chemical Essays_, vol. iii, &c. may be consulted on this subject
with advantage. See _Introduction_.
We will consider, in the next place, the subject of _gunpowder
proof_. The first examination of gunpowder is by rubbing it in the
hands, to find whether it contains any irregular hard lumps. If it
is too black, it is a sign that it is moist, or else, that it has
too much charcoal in it; so, also, if rubbed upon white paper, it
blackens it more than good powder does; but, if it be of a kind
of azure colour, it is a good indication. If on crushing it with
the fingers, the grains break easily, and turn into dust, without
feeling hard, it is a criterion, that it has too much coal; or, if in
pressing it under the fingers upon a smooth hard board, some grains
feel harder than the rest, it is inferred that the sulphur is not
well mixed with the nitre. By blasting two drachms of each sort on a
copper plate, and comparing it with approved powder. In this proof
it should not emit any sparks, nor leave any beads or foulness on
the copper. The method of _burning_, which is commonly employed, Mr.
Robins observes, is to fire a small heap on a clean board, and to
attend nicely to the flame and smoke it produces, and to the marks it
leaves behind on the boards.
Another trial of powder is to expose it to the atmosphere. One pound
of each sort, accurately weighed, is exposed to the atmosphere for
17 or 18 days; during which time, if the materials are pure, it will
not increase any thing material in weight, by attracting moisture
from the air. One hundred pounds of good powder should not absorb
more than twelve ounces, or somewhat less than one per cent. See Mr.
Coleman's account of the manufacture of powder in England, page 110.
To determine the strength of powder in the easiest manner, is by
comparing its effect with improved powder; as, for instance, by using
a given weight of powder, as two ounces, and discharging a ball of a
known weight, say 64 pounds, from an 8 inch mortar. The best cylinder
powder generally gives about 180 feet range, and pit 180, with a ball
and charge of the above weights; but the weakest powder, or powder
that has been reduced, &c. only from 107 to 117 feet.
The practice adopted in England, we are told, is, that the merchant
powder, before it is received into the king's service, is tried
against powder of the same kind made at the king's mills, and it is
received if it gives a range of 1/20 less than the king's powder,
with which it is compared. In this comparison, both sorts are tried
on the same day, and at the same time, and under exactly the same
circumstances.
James (_Mil'y Dictionary_, p. 348) remarks, that the proof of powder
as practised by the board of ordnance, besides that of comparing
it by combustion on paper, is that 2 drachms, when put into the
eprouvette, must raise a weight of 24 pounds to the height of 3-1/2
inches.
According to Bottée and Riffault, before gunpowder is received into
the arsenals of France, for service, it undergoes a variety of
proofs; and the instructions for that purpose are contained under
forty-two heads, embracing, at the same time, the specific duties of
the officer employed for that service. The principal points, however,
refer to a standard proof, made with the eprouvette, and differ, in
no essential part, from the methods practised elsewhere. There is a
uniformity in the French service, which cannot but be admired. In
every thing which relates to the ordnance especially, even in the
most minute details, the French, without doubt, exceed any other
nation.
Having examined the different kinds of proof, not only for
gunpowder, but for cannon and small arms, as established by an act
of parliament, it appears, that musket powder undergoes another
description of proof. A charge of four drachms of fine grain or
musket powder in a musket barrel, should perforate, with a steel
ball, a certain number of half inch wet elm boards, placed 3/4 inch
asunder, and the first 39 feet 10 inches from the barrel. The powder
manufactured at the Royal Powder Mills generally passes through
fifteen or sixteen, and restored powder, from nine to twelve.
There are other contrivances made use of, such as _powder-triers_,
acting by a spring, commonly sold at the shops, and others again that
move a great weight, throwing it upwards, which is an imperfect kind
of eprouvette.
Dr. Hutton is of opinion, that the best eprouvette is a small cannon,
the bore of which is about one inch in diameter, and which is to be
charged with two ounces of powder, and with powder only; as a ball is
not necessary; and the strength of the powder is accurately shown, by
the _arc of the gun's recoil_.
The whole machine is so simple, easy, and expeditious, that, as Dr.
Hutton remarks, the weighing of the powder is the chief part of the
trouble; and so accurate and uniform, that the successive repetition,
or firings, with the same quantity of the same sort of powder, hardly
ever make a difference in the recoil of the one-hundredth part of
itself.
Gregory (_Treatise of Mechanics_, vol. ii, p. 178) has given a more
particular description of the eprouvette of Dr. Hutton; namely, that
it is a small brass gun, 2-1/2 feet long, suspended by a metallic
stem, or rod, turning, by an axis, on a firm and strong frame, by
means of which, the piece oscillates in a circular arch. A little
below the axis, the stem divides into two branches, reaching down to
the gun, to which the lower ends of the branches are fixed, the one
near the muzzle, the other near the breech of the piece. The upper
end of the stem is firmly attached to the axis, which turns very
freely by its extremities in the sockets of the supporting frame; by
which means, the gun and stem vibrate together in a vertical plane,
with a very small degree of friction. The charge is the same we have
mentioned, usually about two ounces, without any ball, and then
fired; by the force of the explosion, the piece is made to recoil or
vibrate, describing an arch or angle, which will be greater or less,
according to the quantity or strength of the powder.
To measure the quantity of recoil, and consequently the strength of
the powder, a circular brazen or silver arch of a convenient extent,
and of a radius equal to its distance below the axis, is fixed
against the descending two branches of the stem, and graduated into
divisions, according to the purpose required by the machine: _viz._
1st. Into equal parts, or _degrees_, for the purpose of determining
the angle actually described in the vibration.
2nd. Into equal parts, according to the _chords_, being, in fact, 100
times the double sines of the half angles, and running up to 100, as
equivalent to 90 degrees.
3d. Into unequal parts, according to the versed sines; they are,
in truth, 100 times the versed sines of our common tables, 141-1/2
corresponding with 90 degrees. These serve to compare the forces.
The divisions in these scales are pointed out by an index, which is
carried on the arch during the oscillation, and then, stopping there,
shows the actual extent of the vibration. Two ounces of powder, give,
on an average, according to the experiments of professor Gregory,
about 36 on the chords, or about 21° on the arch. A more detailed
account, with diagrams, may be seen, by consulting Hutton's Tracts,
vol. iii, p. 153.
The eprouvette constructed by the late Mr. Ramsden, differs from the
preceding simply by the gun's recoiling in a direction parallel to
itself, instead of its vibrating as a pendulum. The gun is suspended
by two hanging frames, which serve to make it rise and fall, during
its recoil and return, so as always to retain the horizontal
direction. The degrees are measured upon a fixed arch, by means of a
moveable index, nearly as in Dr. Hutton's eprouvette.
We remarked, that the common powder-triers are small strong barrels,
in which a determinate quantity of powder is fired, and the force
of expansion measured by the action excited on a strong spring,
or a great weight. The French eprouvette is usually a mortar of
seven inches (French) in caliber, which with three ounces of powder
should throw a copper globe of sixty pounds weight to the distance
of 300 feet. No powder is admitted that does not answer this trial.
This eprouvette, however, has been improved, as we shall mention
hereafter. These methods have been objected to, the former because
the spring is moved by the instantaneous stroke of the flame, and
not by its continued pressure, which is somewhat different; and the
other, on account of the tediousness attending its use, when a large
number of barrels of powder are to be tried.
J. Bodington of London, invented a machine to try the force of
gunpowder. M. the chevalier d'Arcys made an eprouvette on the
principle of Mr. Robins. M. Le Roy proposed to employ the different
elastic forces of inflammable air, but his method has never been
used. M. Tresnel also proposed an eprouvette, which was announced in
the French journal, entitled _Nouvelles de la République des Lettres
et des Arts_, par M. de la Blancherie, for 1782, p. 190.
It is hardly necessary to observe, that the eprouvette has undergone
some improvements: thus, the eprouvette of Darcy consists of a cannon
suspended at the extremity of a bar of iron, and the graduated arc
measures the recoil; the eprouvette of Regnier is nearly the same,
and the arc determines the force of the powder.
A description of mortar-eprouvettes generally, may be seen in the
work of MM. Bottée et Riffault, (_Traité sur l'art de Fabriquer la
poudre à canon_,) and in the Memoirs of Proust (_Journal de Physique_,
tome lxx, _et suiv._), &c.
I saw a model of an improved eprouvette, which appeared to possess
every advantage, at the Ordnance Arsenal near Albany; an index hand
moved in an arc.
Quicklime is said to increase the force of powder. Dr. Baine says,
that three ounces of pulverized quicklime being added to one pound
of gunpowder, its force will be augmented one-third; shake the whole
together, till the white colour of the lime disappears.
The preservation of gunpowder in properly constructed magazines, of
which we will have occasion to speak hereafter, is a subject that
should claim our attention. The greatest difficulty, if any, exists
at sea, and on this head we have a variety of opinions.
Mr. James (_Military Dictionary_, p. 348) says, that it has been
recommended to preserve gunpowder at sea by means of boxes lined with
sheet-lead. M. D. Gentien, a naval officer, tried the experiment by
lodging a quantity of gunpowder and parchment cartridges in a quarter
of the ship which was sheathed in this manner. After they had been
stowed for a considerable time, the gunpowder and cartridges were
found to have suffered little from the moisture; whilst the same
quantity, when lodged in wooden cases, became nearly half destroyed.
It has been recommended to line powder magazines with lead, as a
mean for preserving the powder from dampness. The lead, it seems, so
far attracts moisture, as to condense it. In the last volume of the
_Transactions of the American Philosophical Society_, is a memoir
on _leaden_ cartridges, by Wm. Jones, Esq. the late secretary of
the navy, which, besides preserving the powder, has advantages over
either paper or flannel. See Magazine.
What is termed the _analysis of gunpowder_, is nothing more than the
separation of its component parts, and determining the relative
proportions of its respective ingredients. We may indeed examine
the quality of the nitrate of potassa, by dissolving a portion of
powder in distilled water, and employing the reagents mentioned under
the head of nitre; but for the purpose of separating, as well as
determining the proportion of saline matter, charcoal and sulphur,
it may be readily accomplished in the following manner: Take a given
quantity of gunpowder and affuse it in distilled water sufficient
to dissolve the salt; after suffering it to remain for some time,
applying heat to assist the solution, decant the whole upon a filter
of unsized paper. The saltpetre and other saline matter will pass
through, and the sulphur and charcoal remain on the filter. By
evaporating the solution to dryness, and weighing it, the quantity
of saltpetre will be found; or, after drying the mass on the filter,
and weighing it, by subtracting its weight from that of the original,
it will give the loss sustained, which of course is the saltpetre.
By exposing the mass to a heat sufficient to evaporate the sulphur,
it will be expelled; the loss sustained will indicate its quantity,
and the weight of the residue the proportion of charcoal. The sulphur
may be even separated by subjecting gunpowder itself to the action
of a well regulated heat; it will sublime, and leave the nitre and
charcoal. It takes a much higher temperature to inflame gunpowder
than is required to volatilize sulphur. The method of extracting the
nitre from damaged powder, we have already noticed. See _nitre_.
This process also depends on the solubility of the nitre, and the
insolubility of the charcoal and sulphur. Bishop Watson, in his
_Chemical Essays_, proposed the examination of gunpowder by solution
and sublimation; a process sufficiently accurate. If it should be our
object to ascertain the presence and quantity of foreign substances,
in the saltpetre, this may be accomplished by following the process
already given, viz: by collecting the precipitates, &c. determining
their weights, and making the necessary allowance, for the new
compounds, as the carbonates of lime, sulphate of barytes, muriate of
silver, and the like.
Baumé proposed the analysis of powder by sublimation, in order
to separate the sulphur, using however a graduated heat. Another
mode consists in distilling the powder in a retort with water,
and collecting the sulphur and sulphuretted hydrogen gas, and
then separating the charcoal, &c. A third process was recommended
by Pelletier, after the separation of the nitre, by subliming a
mixture of the residue with mercury, which, however, presents no
advantages. The use of nitric acid has also been recommended, in
order to acidify the sulphur. For this purpose nitric acid is poured
on the residue, and the whole is digested for some time, renewing
the acid as it is decomposed. By this means the carbon, as well as
the sulphur, is acidified, and carbonic acid gas with deutoxide of
azote are disengaged, leaving the sulphuric acid formed by the union
of oxygen with the sulphur, in the remaining fluid, from which it
is separated by nitrate of barytes, and its quantity ascertained by
the sulphate of barytes produced. The proportion of sulphur, in the
sulphuric acid, is then calculated.
Caustic potassa has been employed for the separation of the sulphur
from the charcoal. It unites with the sulphur, forming a sulphuret;
and as sulphuretted hydrogen gas is also produced, the sulphuret must
likewise contain the hydroguretted sulphuret of potassa. The charcoal
is not acted upon.
M. Vito Caravelli, professor of chemistry at Naples, (_Elements
d'Artillerie_, 1773,) has given a more simple process for the
separation of these substances, which depends on their specific
gravity. When mixed with water, the sulphur will deposite, and the
charcoal float on the fluid.
Vauquelin directed his attention to this subject, and has recommended
various processes, not only for the separation of the sulphur and
charcoal, but also the nitre.
The process of Smithson Tennant is nearly of the same nature.
The separation of sulphur from charcoal may be effected more
perfectly, according to Brande, by introducing the mixture into a
small retort furnished with a stop cock, exhausted, and filled with
chlorine gas; the chlorine will unite with the sulphur, forming a
chloride, and leave the charcoal, which may be washed, dried, and
weighed.
Baumé found, that when all the sulphur is expelled which will be
driven off in the heat, a certain portion will still remain, and not
burn away at a lower temperature than will consume the charcoal; so
that to the last the burning residue will smell strongly sulphurous.
This retained portion of sulphur he finds, by the results of many
other experiments, to be very uniformly about one-twenty-fourth part
of the whole sulphur employed; whence, for all common purposes, an
adequate correction may be made, by estimating that the slow weak
combustion of the residue, after the nitre has been extracted,
destroys only 23/24ths of the sulphur instead of the whole. On trying
to separate them by an alkaline solution, he found some of the
sulphur to remain undisturbed, and still adhering to the charcoal.
In consequence of this circumstance, it is recommended, to insure
a perfect analysis, to separate the nitre in the first place from
gunpowder, by hot water, and to treat the residue with nitric acid.
After the sulphur is acidified, the addition of nitrate or muriate
of barytes will separate, effectually, the sulphuric acid from the
fluid, and form a sulphate of barytes; this being collected, washed,
dried, and weighed, will give the quantity of sulphuric acid, and
of sulphur in the acid, by the well known proportion of acid in the
salt, and of sulphur in the acid. One hundred parts of sulphate of
barytes, when perfectly dry, indicate fourteen and a half parts of
sulphur; or, which is the same, according to Chenevix, one hundred
and fifty-five grains denote twenty-two and a half grains of sulphur.
The observations of M. Champy and professor Proust on _humid powder_,
seem to place the quantity of water absorbed, at 8, 10, and 14 per
cent. These proportions, it is evident, depend greatly on the quality
of the nitre; and if deliquescent salts exist in any quantity, the
absorption, and consequently the increase of weight must be greater.
Chemical examination will readily determine this fact.
The different sorts of gunpowder are usually distinguished by
marks on the heads of the barrels. Gunpowder marks are various.
All gunpowder for service is mixed in proportions according to its
strength, so as to bring it as much as possible to a mean and uniform
force. This sort of powder, says Adye, (_Bombardier and Pocket
Gunner_,) is marked with a blue L. G. and the figure 1/2; or with F.
1/2 G. and the figure 3, whose mean force is from 150 to 160 of the
eprouvette. This is the powder used for practice, for experiments,
and for service. The white L. G. or F. G. is a second sort of powder
of this quality. It is sometimes stronger but not so uniform as the
L. G. It is, therefore, generally used in filling shells, or such
other things as do not require accuracy. The red L. G. F. G. denotes
powder in the British service, made at the King's mills, with the
coal made in cylinders, and is used at present only in particular
cases, and in comparisons, and to mix with other sorts to bring them
to a mean force. The figures 1, 2 or 3 denote that the powder is made
from saltpetre, obtained from the rough. Other marks are also in use
to designate the rifle, musket, cannon powder, and the like.
Powder merchants recover damaged gunpowder, by putting a part of the
powder on a sail cloth, and adding an equal quantity of good powder,
which is well mixed with it, and the mixture is then dried.
_Sec. VIII. Of Lampblack._
Lampblack, which is nothing more than a finer kind of coal, is so
named from its being produced and originally made by the combustion
of oil in lamps. It is hardly necessary to say, that it is formed in
the combustion of turpentine, various species of the _pinus_, tar,
pitch, rosin, &c. as all these substances yield it more or less, and
of different qualities. It is the result of imperfect combustion;
for, if the combustion were rapid, and the smoke itself consumed,
we would then have only carbonic acid. This fact is exemplified in
the argand lamp, which, on account of the glass cylinder, consumes
its own smoke. The process of forming lampblack is conducted in
_lampblack houses_. After the combustion has ceased, the soot or
lampblack is swept down, as it collects above and on the sides of
the room. When it is obtained by burning the dregs and coarser parts
of tar, furnaces of a particular construction are used. The smoke is
conveyed through tubes into boxes, each covered with linen, in the
form of a cone. Upon this linen the soot is deposited, from which
it is, from time to time, beaten off into boxes, and afterwards
packed in barrels for sale. There is also a very fine black, superior
in many respects to lampblack, especially in making the ink for
copperplate printers, prepared by carbonizing grape stalks, &c. in
close iron vessels.
There are two kinds of lampblack in common use. One is the light
soot, from burning wood, of the pine and other resinous kinds,
usually made in Sweden. In Sweden the impure turpentine is also burnt
for this purpose. It is collected from incisions made in pine and
fir-trees, and the turpentine is boiled down with a small quantity of
water, and strained, while hot, through a bag; and while this part is
used for another purpose, the dregs and pieces of bark remaining in
the strainer, are burnt in a low oven, whence the smoke is conveyed
through a long passage into a square chamber, which contains a sack,
as above stated, where the greater part of the lampblack collects,
and the remainder is caught in the chamber.
The other kind of lampblack is formed by carbonization, a process
similar to that for preparing the black, called _blue-black_, from
grape stalks, or for preparing the German black, a pigment made by
charring principally the lees of wine and husks of grapes.
The lampblack made in Philadelphia, for the purpose of printers' ink,
is prepared by the combustion of tar. One barrel of Carolina tar will
produce forty pounds of soot or lampblack.
A patent was granted 1798 to a Mr. Row, (_Repository of Arts_, vol.
x.) for a newly invented mineral lampblack. It is nothing more than
the smoke obtained by the combustion of pit coal. In the county of
Sarrbrook on the Rhine, are some establishments for making coke and
lampblack at the same time; and from 100 lbs. of coal, 33 lbs. of
coke, and 3-1/2 of lampblack are obtained. Jeanson (_Archives des
Découvertes_, &c. i, p. 21) has described a process for carbonizing
oil.
Lampblack has the same chemical properties as charcoal, and being
remarkably fine, and containing sometimes a portion of oil, is used
on that account in the composition of some fire-works. Its quality
may be known by its colour, and, when burnt, leaving no residue. It
may be sufficient to remark, that like charcoal, it decomposes nitric
acid; and the nitrates, when mixed with it, and projected into a
red-hot crucible, will deflagrate or produce a vivid combustion. It
may therefore be used in all kinds of fire-works, in which charcoal
is employed. Concentrated nitric acid, when poured on lampblack,
previously dried, will produce combustion. It is to the carbon, as
well as the hydrogen, in oil of turpentine, that turpentine inflames
when brought in contact with nitric acid; and although much charcoal
is deposited, yet a considerable part passes off in the state of
carbonic acid gas. By a proper treatment, lampblack like charcoal
may be converted into artificial tannin by nitric acid. It has also
antiseptic qualities; but to be used for this purpose it should first
be exposed to heat, in order to drive off any oil which it may have
contracted, or with which it might be contaminated. The quality of
lampblack may, we suspect, be improved by bringing it to a state of
ignition in close iron vessels. If required intensely black, as for
the making of printers' ink, this process might be advantageously
used. Mixed with gum water, it makes a durable writing ink, or,
according to Mr. Close, by mixing it with a solution of copal in oil
of lavender. This ink is not, like the common kind, acted upon by
acids.
_Sec. IX. Of Soot._
Soot, or that substance formed by the combustion of wood, &c.
which collects in chimnies, is used in some of the pyrotechnical
preparations, partly to assist the flame, and partly to modify its
appearance. It is found, that soot, produced by the combustion of
wood, is formed by the condensation of the carbon evolved in the
smoke. It also contains volatile products, the nature of which,
depends on the kind of combustible. Wood-soot is considered a good
manure, on account of the carbon and some volatile salts, it is
said to contain. That it contains ammonia, is evident, since it may
be detected by experiment; and that this alkali is combined with
carbonic acid, and sometimes with muriatic acid, a number of facts
prove. Soot, then, when used in fire-works, may, like sal ammoniac,
but in a lesser degree, produce a particular coloured flame. When
soot is well washed in water, in order to free it from saline and
other soluble matter, and probably from pyroacetic acid, and then
pulverized, it forms the pigment called _bistre_. It is a fact,
that the excrement of some animals, the camel for instance, which
feed on saline vegetables, when burnt, will yield a soot, which
contains an abundance of muriate of ammonia, or sal ammoniac. Hence,
by re-subliming this soot, sal ammoniac was originally prepared in
Egypt. The quantity of muriate of ammonia, contained in the soot of
camels' dung, is considerable. It is found that 26 lbs. of soot yield
on an average 6 lbs. of that salt; See _Sal Ammoniac_. Camels' dung,
and in fact the dried excrement of animals, furnish a very good fuel.
In Egypt it is used with advantage. The soot of oil, &c. is of a
different kind; it is the substance, which forms our lampblack.
_Sec. X. Of Turpentine, Rosin, and Pitch._
All these substances enter into the composition of fire-works, either
to increase the rapidity of combustion, as in incendiary fire-works,
or, in some cases, as with rosin, to produce a coloured flame. That
they contain carbon and hydrogen, as their principal ingredients, is
well known; to which we may attribute their rapid combustion, and the
facility with which they decompose nitrous salts. The Greek fire, for
example, owed, it is said, its powerful effect to turpentine, which,
with other substances employed, made the composition remarkably
inflammable, and the decomposition of the nitre, (which some say it
contained) so rapid, as even to defy the action of water.
All of the turpentines are obtained from different species of pinus.
Common turpentine is the resinous juice, which exudes chiefly from
the _Pinus Sylvestris_, or Scotch fir, and is obtained by boring
holes into the trunks of the trees, early in the spring, and placing
vessels beneath for its reception. This turpentine, and in fact all
others, are composed of rosin and a volatile oil. The latter is
obtained by distilling the turpentine with water. It passes over
with the water, from which it is afterwards separated, and is then
known by the name of the essential oil, or spirit of turpentine. The
substance, remaining in the still, is common rosin, or yellow rosin,
known likewise by the names of _fidlers' rosin_ and _colophony_. Tar
is also obtained from the roots and refuse parts of the fir tree, by
cutting them in billets, piling these in a proper manner, in pits or
ovens, formed for the purpose, covering them partly over, and setting
them on fire. During the combustion, a black and thick matter, which
is tar, falls to the bottom, and is conducted into barrels.
Pitch is nothing more than tar boiled down to a solid consistence; it
is usually made, however, by melting together coarse hard rosin, and
an equal quantity of tar. The ancient pitch possessed a flavour and
fragrance. White pitch is the same as the white turpentine.
Melted pitch, sulphur, and camphor, mixed, when nearly cold,
with pulverized saltpetre, and afterwards thinned with spirit of
turpentine, will form a composition, that is very inflammable, and
will almost resist the action of water. A similar composition must
have formed the Greek fire, of which, according to Beckman, there
were several kinds.
The turpentine trees furnish various products: Thus, the Pinus
Abies, or spruce fir, yields the Burgundy pitch, and its branches
produce the Essence of Spruce; but other species of pinus are used
for the same purpose, which are nearly allied to it, and which grow
abundantly in Canada. From the _Pinus laryx_, or larch, Venice
Turpentine is obtained; but that sold, is usually made by melting
rosin, and adding the spirit of turpentine. From the sap of the
larch, the Russians prepare a gummy substance, known in Russia by the
name of _Orenburg gum_. Turpentine is extracted in France, in great
quantity, from the _pinus maratima_. Gallipot, colophony, tar, pitch,
&c. are likewise obtained from it.
The turpentine of cedar, according to Dr. Pocoke (_Travels through
Egypt_) was employed by the Egyptians for embalming, the operation
being performed in several ways. It was injected, and used with salt,
nitre, &c.
Pitch, tar, and turpentine all enter into sundry compositions, used
in war. The different incendiary preparations, noticed in the last
part of the work, are composed, in general, of either one or all of
these substances. Their use is obvious. Being very inflammable, and
brought in contact with gunpowder, nitrate of potassa, &c. they burn
with great rapidity, and consume every thing before them. Hence the
tourteaux of the French, tarred links, and fascines, carcasses, &c.
owe their effect to the presence of these substances.
Rosins are considered to be volatile oils, saturated with oxygen.
_Thus_, or frankincense, of which there are several varieties, has
been long used in fire-works; it is frequently employed in the
composition of odoriferous fire. It is obtained from the pinus
abies, and appears in _tears_. During winter, the wounds made in fir
trees become incrusted with a brittle substance, called _barras_ or
_gallipot_, consisting of rosin united with a small portion of oil.
All rosins, according to the experiments of Gay-Lussac, and Thenard,
(_Recherches physico-chimiques_) are composed of a great quantity of
carbon and hydrogen, united with a small quantity of oxygen. To this,
we attribute their great inflammability, and it enables us to account
for the rapid decomposition of nitre, in those preparations, in which
nitre and resinous substances are employed. See _General Theory of
Pyrotechny_, sec. ii.
For the accension which takes place by mixing oil of turpentine and
nitric acid, see the properties of nitric acid, under the head of
_nitre_.
Morey (_Silliman's Journal_, vol. ii, p. 121) observes, that a
small quantity of spirit of turpentine being added to a mixture of
iron-filings, sulphuric acid, and water, the hydrogen gas produced,
will burn with a very pleasant white flame, and without smoke. He
also observes, that, if the vapour of spirit of turpentine be made to
pass through a tube, covered at the upper end with a fine wire gauze,
it burns with much smoke; but, if a quantity of atmospheric air be
allowed to mix with it, the smoke ceases, and the flame continues
white. If more still be added, the flame lessens, and becomes partly
blue. By adding still more and more, it will burn with a very small
flame, entirely blue, and with a singular musical sound. If still
more be added, the flame, and every ray of light cease; but that the
combustion still continues, is certain, from the explosive detonating
noise, continuing to be distinctly heard.
Mr. Morey further remarks, that, if tar, containing a considerable
proportion of water, is dropped on brick or metal, at a temperature,
which will readily evaporate them, the vapours will burn with white
shooting streaks, much flame, and without smoke, while the water
lasts. Inflamed drops of tar, burn, while falling, with a red
flame, and much smoke; but, on reaching boiling water, the smoke
instantly disappears, and streaks of a white flame shoot up. He also
says, that, if water in one cylinder be made to boil, and the steam
be led to the bottom of another, containing rosin, or tar, at a
high temperature, after passing up through it, the water, together
with the vapourized portion of the rosin or tar, will, when the
preparations are properly regulated, burn with an intense _white_
flame, and _no smoke_; much the greater part of which appears, (by
alternately shutting the steam out, or letting it in) to be derived
from the water; and also, that if steam be led over the surface of
tar in a cylinder, and made to force out a small stream of it through
a pipe, into which a quantity of steam is also admitted, and made to
mix intimately with it, they burn, with a great body of flame and
intense heat, and without smoke, provided the proportions are well
regulated. These facts are remarkable, and may probably lead to some
useful applications. That water is decomposed, appears more than
probable. If water is thrown, in considerable quantities, on oil or
tar, in a state of inflammation, as Morey observes, the flame is
greatly increased; and if ever so small a drop of water fall into oil
at a temperature near boiling, an explosion will take place. He draws
the following conclusion, from these circumstances; that we have only
to pass the steam of water through oil, heated to the temperature, at
which it boils, or takes fire, to produce combustion.
_Sec. XI. Of Common Coal, or Pitcoal._
All the variety of coals, belonging to the coal family, are composed
principally of charcoal and bitumen, with small quantities of earthy,
and metallic matter. Whether we consider the formation of coal,
the localities or situation in which it occurs, whether in beds or
strata, accompanying other minerals, such as clay-slate, bituminous
schistus, sandstone, &c. is of no moment, except so far as the
situation in which it is found, indicates or determines its character
and qualities. The different kinds of coal owe their variety to the
presence or absence of bituminous matter, whether great or small, the
quantity of the carbonaceous ingredient, and the presence or absence
of anthracite, and other foreign substances. Coal, which is, or ought
to be preferred in fire-works, should contain the greatest quantity
of bituminous matter; and, while it contains the due proportion of
carbon, should be entirely free from anthracite. Coal, and all other
inflammable fossils, are characterized by their inflammability,
insolubility in water, alcohol, and acids, and by their specific
gravity, which scarcely exceeds 2, unless loaded with foreign
matter. Coal surcharged with bitumen, burns with a bright flame, and,
by distillation, affords more carburetted hydrogen gas, which is used
for _gas light_. Common coal, or pitcoal, burns in cakes, more or
less, during combustion. Besides charcoal and bitumen, it contains
sometimes pyrites, sulphate of iron, and earth. Slate-coal, however,
contains more clay.
The collieries, from which pitcoal is obtained, are more or less
extensive in England, and elsewhere. Immense beds of coal are found
near Pittsburgh, and Richmond. The Lehigh, and other localities in
the United States, produce it also in abundance, but of various
qualities. Coal districts, or places in which it is found, may be
considered a valuable acquisition to a country; and as coal is so
essential in many manufactories, it is a satisfaction to know, that
our resources in this particular, are almost inexhaustible;--a fact,
which shows, that, while our national industry is the main pillar
of national independence, in its true acceptation, the arts, which
require a supply of coal, will, for centuries to come, be abundantly
furnished with it.
When coal is exposed to the action of heat, in iron retorts or
cylinders for the preparation of coal gas, or when it is exposed
to heat in coke-ovens, the bitumen, &c. are disengaged, and there
remains a coal called coke. Coke, therefore, is nothing more than
charred pitcoal.
Mr. Mushet made some valuable experiments on the carbonization
and incineration of coals. He found that the Scotch cannel-coal
afforded 56.57 volatile matter, 39.43 charcoal, and 4 ashes; while
the stone-coal, found under basalt, gave 16.66 volatile matter,
69.74 charcoal, and 13.6 ashes, and oak wood, 80.00 volatile matter,
19.5 charcoal, and 0.5 ashes. The quantity of gas, however, depends
entirely on the quality of the coal. A temperature of about 600° to
700° is sufficient to disengage it. A pound of good cannel coal,
properly treated in a small apparatus, will yield five cubic feet of
gas, equivalent in illuminating power to a mould candle, six in the
pound. One pound of coal, on a large scale, affords only 3-1/2 cubic
feet of gas. A gas jet, which consumes half a cubic foot per hour,
gives a steady light equal to that of a candle of the above-mentioned
size.
The cannel coal, known in Scotland by the name of parrot coal, is
very inflammable, takes fire immediately, and produces a brilliant
flame. It is used by the poor as a substitute for candles. This coal,
we have seen, furnishes an abundance of carburetted hydrogen gas. It
has the appearance of jet, and admits of being turned in a lathe.
Stone coal, Kilkenny coal, Welch coal, and glance coal consist almost
entirely of charcoal; and hence, when laid on burning coals, they
become red-hot, emit a blue lambent flame, in the same manner as
charcoal, and at length are wholly consumed, leaving behind a portion
of red ashes. They burn without smoke or soot.
The pitch coal, which has a brownish-black colour, and is generally
found massive in plates, the bovey coal, called brown coal, and
bituminous wood, with the anthracite coal, and some others of lesser
note, form the remaining varieties of coal.
When coal is employed in fire-works, it is to be pulverized, and
sifted in the usual way. For some purposes it is preferred to
charcoal, in consequence of the bitumen it contains, which appears to
contribute to the rapidity of the combustion. It is to be observed,
that, as the base of coal is carbon, its action is the same as
charcoal, and therefore, by producing the same effects, or nearly
so, as charcoal itself, the phenomena it presents are analogous.
As 12.709 parts of carbon, according to Kirwan, are required to
decompose 100 parts of nitrate of potassa, we may readily ascertain
the quantity of real carbon in any specimen of coal. According to
Kirwan, 50 grains of Kilkenny coal will decompose 480 grains of
nitrate of potassa, from which it is inferred, that ten grains would
have decomposed 96 of nitrate of potassa, precisely the same quantity
of charcoal, which would have produced the same effect. Therefore,
Kilkenny coal is composed almost entirely of carbon. Cannel coal,
when treated in the same manner with nitrate of potassa, left a
residuum of 3.12 in the hundred parts of earthy ashes; and 66.5 of
it were required to decompose 480 grains of nitrate of potassa, but
50 of charcoal would have been sufficient. From this experiment,
it appears, that 66.5 grains of cannel coal contain 50 grains of
charcoal, and 2.08 of earth; the remaining 14.42 grains must be
bitumen. In a similar manner, by knowing the quantity of coal
required to decompose a given quantity of nitrate of potassa, when
melted in a crucible, the quantity of carbon in any variety of this
substance may be ascertained.
With respect to the earthy and metallic ingredients of coal, we may
ascertain them by burning the coal, with free access of air. What
remains unburnt must be considered an impurity. Its weight may be
ascertained, and its nature by analysis. As the object, however, is
generally to determine the relative proportion of combustible matter,
or carbon, which different species of coal are capable of yielding,
that point may be determined in the manner already stated.
That coal originates from vegetables, whatever opinion may be formed
to the contrary, we may fairly infer from a variety of vegetable
remains, and impressions of animals that are both found in the strata
of coal, and in earthy strata above and below them. Of its submarine
origin, there can also be no doubt; or why do we find in it shells,
the impression of fish, and other productions of the ocean? That
coals _grow like vegetables_, an opinion with the uninformed, is
contrary to fact, and the nature of things.
We may notice, in this place, another substance which sometimes is
found partially carbonized; we mean turf.
Turf or peat, obtained from morasses, consists of a multitude or
congeries of vegetable fibres, partly in a decomposed state, and is
frequently so inflammable as to inflame by a spark. Very extensive
morasses are found in some countries from which the inhabitants are
supplied with fuel. Some improvements in the manner of preparing
turf for use, have been made; that of charring it in kilns is one.
By this process it kindles sooner, burns with less air, and forms
a moderate and uniform fire, without much smoke, though it is not
so lasting as that produced by turf. The method of reducing turf to
coal is still practised in some parts of Bohemia, Silesia, and Upper
Saxony, which was first proposed in 1669, by John Joachim Becher,
who also recommended, at that time, a process for depriving coals
of their _sulphur_, by burning them in an oven, and the use of the
oil procured from them. What are our modern patents on this subject?
What are lord Dundonald's coke ovens and coal tar? Are they original?
Boyle (_Usefulness of Natural Philosophy_,) speaks of Becher's
invention. Anderson, (_History of Commerce_,) however, observes,
that something of the kind was attempted before Becher's time; for
in the year 1627, John Hacket and Octavius Strada obtained a patent
for their invention of rendering coals as "useful as wood for fuel in
houses, without hurting any thing by their smoke."
With respect to turf, it appears that Hans Charles von Carlowitz,
to save wood, introduced the use of it in Saxony, in the smelting
houses, in 1708.
Turf has been known for a long time. It was used from the earliest
periods, in the greater part of Lower Saxony, and throughout the
Netherlands; as is fully proved by Pliny's account of the Chauci,
who inhabited that part of Germany. Pliny (_Hist. Nat. lib._ xvi, c.
i.) observes, that they pressed together with their hands, a kind of
mossy earth which they dried by the wind rather than by the sun, and
which they used, not only for cooking their victuals, but also for
warming their bodies. We also read that a morass in Thessaly, having
become dry, took fire, and the same thing ensued in some part of
Russia, where a morass burned several days and did much damage. Very
dry turf is nearly as inflammable as spunk, and when prepared with
nitre, has been used for the same purpose. See _Pyrotechnical sponge_.
Ure (_Chemical Dictionary_) observes, that "turf has been charred
lately in France, it is said by a peculiar process, &c." The truth
is, that the _charring_ of turf is by no means a recent invention, as
we stated above. Sonnini (_Journal_, &c.) says, that it is superior
to wood. It kindles slower than charcoal of wood, but emits more
flame and burns longer. In a gold-smith's furnace, it fused eleven
ounces of gold in eight minutes, while wood charcoal required sixteen.
Turf frequently contains phosphoric acid; for bogs or morasses, and
bog-iron ores abound, more or less with it, in different states of
combination. The _siderite_ of Bergmann which he supposed to be a
peculiar metal, and found in bog-ore, is a phosphate of iron. The
native Prussian blue, which also occurs in such localities, is
generally admitted to be a combination of phosphoric acid iron and
alumina.
_Sec. XII. Of Naphtha, Petroleum, and Asphaltum._
Naphtha, petroleum, and asphaltum are all modifications of bituminous
oil; and as they are all inflammable, naphtha being the most so, they
have been used in the preparation of fire-works.
It will be sufficient to remark, that naphtha or rock oil is a yellow
or brownish bituminous fluid, of a strong, penetrating odour, and
so light as to float on spirits of wine. By exposure to the air, it
acquires the consistence of petroleum. It takes fire on the approach
of a lighted taper, and burns with a bluish flame, yielding a thick
smoke. Plutarch and Pliny both affirm, that the substance with which
Medea destroyed Creusa, the daughter of Creon, was naphtha. She sent
a dress to the princess, which had been immersed in, or covered over
with the oil, and which burst into flames as soon as she approached
the fire of the altar. Plutarch relates that Alexander the great,
was amused and astonished with the effects of naphtha, which were
exhibited to him at Ecbatana. On the shores of the Caspian sea, it
is burnt in lamps, instead of oil. There are copious springs of this
oil in that neighbourhood, and it is sometimes obtained by distilling
bituminous substances.
Hanway (_Travels through Russia into Persia_, i, 263,) mentions the
naphtha of Baku, and remarks that the earth is strongly impregnated
with it; for, he adds, by taking up two or three inches of the
surface, and applying a live coal, the part which is so uncovered,
immediately takes fire, almost before the coal touches the earth.
Eight horses were consumed by the fire from naphtha, being under a
roof where the surface of the ground was turned up, and, by some
accident took fire. A cane, or tube, even of paper, set two inches
in the ground, and the top of it touched with a live coal, and blown
upon, immediately emits a flame, without hurting either the cane or
paper, provided the edges be covered with clay. Three or four of
these lighted canes will boil water in a pot.
Pinkerton, (_Petralogia_ ii, p. 148,) speaks of the naphtha of Baku,
which exists on the western side of the Caspian sea, being carried to
Constantinople, "where it formed the chief ingredient of the noted
composition called the Grecian Fire; which, burning with increased
intensity under water, became a most formidable instrument against an
inimical fleet." See _Greek fire_.
Naphtha is obtained of several qualities by suffering it to remain
in pits or reservoirs. The Persians, who use it in their lamps, and
to boil their food, find it to burn best with a small mixture of
ashes. They keep it at a small distance from their houses, in earthen
vessels, under ground, to prevent any accident by fire, of which it
is extremely susceptible.
Hanway speaks also of what is called the _everlasting fire_, about
ten miles from Baku, which is an object of devotion to the followers
of Zoroaster. Near the altar of their temple, he observes, is a
large hollow cane, from the end of which issues a blue flame, which
the Indians pretend has continued to burn ever since the flood, and
which, they fancy, will last to the end of the world.
We have no hesitation in believing, that the ancients made use of
this oil in their exhibitions; and, from its properties, that when
mixed with other substances, it would make a brilliant fire-work.
Petroleum, called also mineral tar, is less fluid and less
transparent than naphtha. It has an oily consistence, more or less
viscid. It occurs of a black or brown colour. It burns rapidly,
but not so readily as naphtha, and exhales a black smoke. By
distillation, it forms a liquid like naphtha, and leaves a thick tar
in the retort.
It exudes from rocks, is found in wells, &c. In Pegu, the wells
furnish annually 400,000 hogsheads. It is used there in the place
of oil for lamps. When boiled with rosin, it is used for painting
houses, and the bottoms of vessels. In the embalming of dead bodies,
it was employed by the ancient Egyptians; and, in some countries,
clay, soaked in it, is used as fuel.
It is found in the United States, in Kentucky, Ohio, the western
parts of Pennsylvania, in New York at the Seneca lake, &c. The Seneca
or Genessee oil is the same bitumen.
When petroleum is exposed to the atmosphere, it acquires a greater
degree of consistence, and passes into another bituminous substance,
called maltha. This has the properties, and frequently the appearance
of pitch. When burnt, it yields more smoke and soot than petroleum.
According to its original meaning, it signifies a kind of cement;
and the maltha mentioned by Pliny, Heineccius, Festus, and others,
which was employed in the same manner as our modern sealing wax, was
a mixture of pitch and wax, and was also used to make reservoirs,
pipes, &c. water-tight. Maltha also sometimes resembles wax. Mr.
Kirwan, however, gave it the name of mineral tallow.
Mineral or Barbadoes tar is somewhat thicker than petroleum, and
nearly of the consistence of common tar. It is used for the same
purposes as the ordinary petroleum. Elastic bitumen, a variety
between the softer and harder bitumens, resembles caoutchouc. It
burns with a bright flame, and bituminous odour.
Asphaltum, or solid bitumen, is much harder than pitch, brittle, and
of a brownish-black colour. It burns freely, and leaves but little
residue. In Judea, it is found on the waters of the Dead sea, or the
lake of Asphaltes. It is also called _Jews' pitch_. It was employed
by the Egyptians for embalming under the name of _mumia mineralis_.
Both maltha and asphaltum were used by the ancients as a cement.
The walls of Babylon were cemented with these substances, as
obtained from the river Is, which falls into the Euphrates. It may
be observed, that those countries, which yield bitumen, contain
salt springs, and it frequently accompanies pyrites. Limestone,
particularly the black, contains it, and the colour is often owing
to its presence. The _stink stone_, or bituminous carbonate of
lime, is of this kind. The retinasphaltum, a combination of bitumen
and earth, having a yellow colour, burns with a bright flame, and
fragrant odour, which at last becomes bituminous. Many stones, and
particularly some of the black marbles, owe their colour to bitumen;
hence they burn white. The bituminous schistus, or bituminous shale,
sometimes contains so much of this substance as to burn in the fire.
Jet is a mineral of a black colour, and resembles the cannel coal.
It is inflammable, producing a green flame, with a strong bituminous
odour.
With respect to bitumens, we may observe, that they all possess one
character, that of being inflammable; and that they are more or less
so in proportion as they partake of the principle of naphtha; or, at
least, the rapidity of their combustion depends upon the presence of
this oil. The following additional facts, therefore, with respect to
naphtha, may be interesting: Certain liquids have the property of
uniting with naphtha, which has also the property of dissolving and
combining with solid substances, of which the following examples may
be stated:
At the degree of ebullition, it dissolves sulphur, which, on
cooling, is in part deposited in needle-form crystals. At the same
temperature, it also dissolves phosphorus, part of which is again
separated.
It unites also with iodine. With camphor, it also combines, and in
large quantity. It takes up a much larger proportion of pitch. In the
cold, its action on wax is feeble, but assisted by heat, it unites
with it in all proportions. On lac and copal, its action is feeble.
In the cold, it does not dissolve caoutchouc; but when assisted by
heat, it dissolves this substance, though not completely. These facts
may determine its action in certain mixtures.
According to Theodore de Saussure's Analysis, (_Bibliot.
Universelle_, iv, p. 116), it appears, that naphtha is composed of
87.60 carbon, and 12.78 hydrogen.
_Sec. XIII. Of Oil of Spike._
This oil is principally used as a vehicle for mixing the ingredients
of some kinds of fire-works; and, although it is employed in that
way, yet it has also an effect in combustion, having similar
properties with liquid bitumen. It enters into the composition of
some of the preparations, and perhaps is equally good as liquid
bitumen. Indeed, the oil of spike, as sold in the shops, and
used principally by farriers as an embrocation for horses, is an
artificial preparation, made by mixing together about five ounces of
Barbadoes tar, with a pint of the spirit of turpentine.
_Sec. XIV. Of Amber._
Amber, succinum, karabe, the electron of the ancients, which are
synonimous terms, is very inflammable. A piece of it, put on the
point of a knife, and set on fire, will burn entirely away, emitting,
at the same time, a white smoke, and a somewhat agreeable odour. It
is used in the composition of fire-works, and particularly in some
kinds of rockets. All the preparation it undergoes, when thus used,
is to reduce it to powder in a mortar, and to pass it through a fine
sieve. It also forms a part of the composition of odoriferous fire;
but the formulæ for the latter are various.
Amber is of various colours, either yellowish, white, or
honey-yellow. It is translucent, and sometimes transparent. It may
be turned or polished. It occurs in grains or in irregular masses.
Alluvial deposites of sand, gravel, &c. frequently contain it. It is
also found with bituminous wood, brittle lignite, or jet, and with
other substances. It has been discovered in New-Jersey, near Trenton,
in alluvial soil. Naturalists believe, that amber was once a resinous
juice. Masses weighing 20 lbs. have been found. Sometimes it contains
insects. It is formed into beads and the like. As amber becomes
electric by friction, and the ancients called it electron, the term
electricity is derived from it. By distillation, it yields both an
acid, (the succinic), and an oil. Jet is usually considered black
amber.
We may introduce here a few remarks respecting ambergris:
Ambergris is a substance, which has a peculiar fragrance, and for
that reason is used as a perfume, and may be employed like similar
substances in odoriferous fire. As to its origin, we have no certain
account; but it seems, from its general properties, to be formed in
the same manner as bituminous substances, although it is mostly found
on the sea-shore, where it has been probably washed up from the sea.
Ambergris is found principally on the shores of Ceylon, and is known
to be good, by laying some of it on a very hot knife, when, if pure,
it will not only melt and run like wax, but entirely evaporate,
leaving no residue.
Ambergris, on account of its price, (the retail price in London
being a guinea per ounce), is frequently adulterated with various
mixtures of benzoin, labdanum, meal, &c. scented with musk. But pure
ambergris, when heated, has a greasy feel, and appearance, and is
soluble in hot ether and alcohol.
_Sec. XV. Of Camphor._
Camphor is a resinous substance, although generally called a gum,
which has a peculiar, and powerful smell. It is obtained principally
from the _Laurus Camphora_. It is extracted from this, and other
trees in the East Indies. We are informed, that, in Borneo and
Sumatra, the larger pieces which contain the most camphor, are picked
out with sharp instruments. The Chinese cut off the branches, chop
them small, and place them in spring water. They are then boiled, and
stirred with a stick. As soon as the camphor is observed to adhere to
the stick, the fluid is strained. It is then poured into a basin, and
the camphor separates, in Japan, the roots and the extremities of the
branches are steamed. It is also obtained by sublimation. The roots,
wood, and leaves are all boiled in large iron pots, and the camphor
is collected on straw, placed in a tubular head.
With respect to the refining of crude camphor, in order to produce
_heads_, as they are called, and to free it from impurities, the
operation is nothing more than sublimation. Sublimers made of glass
are used; and into each, the camphor, along with a small portion of
lime, is introduced, and they are then placed in a sand bath. Heat is
applied, and the pure camphor rises and attaches itself to the upper
part of the vessel, forming the refined camphor.
The general properties of camphor are the following: It is not
altered by the atmospheric air, but is volatilized during warm
weather. It is insoluble in water; is soluble in alcohol, forming
the spirit of camphor, and also in volatile and fixed oils. It is
not acted upon by the alkalies. It is dissolved in acids without
effervescence, and by some it is decomposed. Nitric acid converts
it into a peculiar acid, called the camphoric. It melts between 300
and 400 degrees. It takes fire, and burns with a white flame, and,
generally, while it presents the character of a resin, it shows, by
its combustion, like other inflammable bodies, that it contains, in
its composition, a large quantity of carbon and hydrogen.
There are several species of camphor, which have been examined by
chemists and which differ in their properties. These are, common
camphor, the camphor of volatile oils, and the artificial camphor,
formed by treating oil of turpentine with muriatic acid.
The base of camphor forms a constituent part of some volatile oils,
which are in a liquid state; and for its separation, it appears to
require a combination with oxygen.
Camphor may be apparently set on fire by means of water, an
experiment, which is nothing more than producing chemical action by
it, in the following manner: Put a portion of nitrate of copper on
some tin-foil, along with camphor; then by adding some water, and
quickly wrapping the foil up, pressing the edges close, it will
inflame, and sparks of fire be produced.
Camphor has been used in the manufacture of candles. For this
purpose, it is dissolved in brandy, and the wick, composed of
equal parts of cotton and linen, is dipped in. It is then dried,
and covered, in the usual manner, with tallow or wax. The tallow,
recommended as the best for candles, is a combination of equal parts
of mutton and beef suet.
Camphor is very soluble in acetic acid, which is highly inflammable.
This solution is decomposed by water. When combined with essential
oils, it forms aromatic vinegar. Romieu has observed that small
pieces of camphor floating on water have a rotary motion.
Camphor enters into a composition, which is used to determine, like
a barometer, the state of the weather, and the changes it undergoes.
According to the _Journal de Pharmacie_, 1815, some experiments were
made in France on the fluid taken out of one of the English weather
gauges. The liquid contained water and alcohol, was strong with
camphor, and reddened litmus paper. The tube contained 3-1/2 ounces.
On analysis, its contents were found to be, 24 grains of alum, 120
grains of camphor, and enough water to dissolve the former, and
alcohol to dissolve the latter. A similar composition was made, and
put into a tube, which, it seems, had the same effect. The tube is
hermetically sealed. M. Cadet observes, that the _prognosticator_,
made in Paris many years ago, was a similar preparation.
Although, according to Cadet, this contrivance cannot be depended
upon, as the appearances it presents are not regular; yet, as the
effect is produced by heat, as well as light and electricity, the
following summary may be added:
1. In fair weather, the composition remains at the bottom, and the
liquor is clear.
2. Before rain, it will rise a little; the liquor will be clear,
having merely a star floating in it.
3. Before a storm, it will rise to the surface, the liquor will
appear troubled. These appearances may be seen 24 hours before the
change in the weather takes place.
4. In winter, it is higher than common. During a snow, it will be
very white, and pieces are seen in motion.
5. In settled weather in summer, and when warm, the composition will
be low.
6. To know from what quarter wind will come, the composition will
remain attached on the opposite side of the bottle to that from which
it is expected.
Camphor has been burnt, like ether and alcohol, by platinum wire,
previously heated. Dr. Ure observes, that a cylinder of camphor may
be used for both wick and spirit, in the aphlogistic lamp; and the
ignition is very bright, while an odoriferous vapour is exhaled. By
adding various essential oils in small quantities to the alcohol
of the lamp, various _aromas_ may be made to perfume the air of an
apartment. See _Scented Fires for rooms_.
Camphor is employed in those fire-works chiefly, which are exhibited
in rooms; its expense being an objection to its use in large
exhibitions. In what are termed perfumed pastes, or mixtures, scented
fire, or odoriferous fire-works, it is used in abundance: in fact,
it enters into nearly all the compositions of this kind. Camphor,
besides producing, alone, a white flame, gives a brilliant light,
and, when mixed with other substances, adds greatly to the appearance
of the flame; and, giving out a powerful odour, destroys, in a
measure, the disagreeable smell arising from the combustion of the
sulphur and nitre.
By referring to the article on Greek fire, and some incendiary
preparations used in war, it will be seen, that camphor is an
important constituent. As camphor is very combustible, and will
even burn on the surface of water, it is well adapted for all those
purposes. We have already spoken of the Greek fire; and it seems,
that the peculiar character of that fire, of burning in water, was
owing to the presence of camphor. This opinion appears plausible,
when we consider, that some preparations _have been_ made with
camphor, which had the property of burning on water.
Camphor may be pulverized by the assistance of, and brought into
intimate mixture with, nitre and sulphur; because the former, in
particular, tends to divide it. But it may be pulverized separately,
and afterwards added to the composition, by rubbing it in a mortar
with a small quantity of alcohol, or spirit of wine; or, if this
cannot be had, with fourth proof brandy. As camphor is very
inflammable, its effects, when mixed with saltpetre and fired, are
much the same as those produced by other resins, or concrete oils.
A combustion, more or less rapid, ensues, and, while the nitre
itself is decomposed, the camphor also undergoes the same change,
producing both water and carbonic acid, from the union of two of its
elements, the hydrogen and carbon, with the oxygen of the nitric
acid. In all cases, in which camphor is employed in artificial
fire-works, although its own flame is _white_, it may assist in
increasing the flame, which, however, is modified, according to the
substances, which enter into the composition. These may not retard
its combustion, but, nevertheless, may change the appearance of the
flame; as is the case, when we employ the filings of iron, steel,
brass, or zinc, sal ammoniac, rosin, saw-dust, and other substances,
which usually form a part of such mixtures. Upon the whole, then, we
may consider, that camphor acts in fire-works; 1st, as an inflammable
body; 2ndly, that, besides being in a great measure decomposed, a
portion of it is evaporated, and communicates, to the surrounding
atmosphere, a peculiar smell, which is recognised in the odoriferous
fire-works; 3rdly, that, while it acts in taking a part of the oxygen
from the nitric acid of the nitre, it assists in the decomposition
of this salt, more especially if it be mixed separately with the
nitre; 4thly, that, in all instances of its combustion, while it
acts primarily on the nitre, with the oxygen of which it forms both
water and carbonic acid, it, at the same time, increases the flame,
which may be either white, red, or yellow, according to the other
substances employed; and, finally, it may be thrown out in the
state of combustion, and receive, for the further support of its
combustion, the oxygen of the air, and hence produce a white exterior
flame, while that in the immediate vicinity of the composition may
be more or less coloured. But its application, the proportions in
which it is used, as well as the kind of fire-works to which it is
applicable, will be considered at large in other parts of the work.
The great inflammability of camphor is to be ascribed to its
containing a _large_ quantity of carbon and hydrogen, and a _small_
quantity of oxygen.
There is a preparation, called artificial camphor, that is formed by
passing muriatic acid gas through spirit of turpentine. It inflames
with facility, and burns, without leaving any residue. Might not
this preparation be economically employed, in lieu of camphor, for
incendiary fire-works?
_Sect. XVI. Of Gum Benzoin, and Benzoic acid._
Gum Benzoin, or Benjamin, is considered a solid balsam, and is the
production of a tree, which grows in Sumatra, &c. called the _styrax
benzoe_. It is obtained from this tree by incision, a tree yielding
three or four pounds. It is a brittle substance, sometimes in the
form of yellowish-white tears and called, from that circumstance,
almond benzoin. Besides a resinous substance, it contains an acid,
called the benzoic or _flowers of benzoin_, a substance similar to
balsam of Peru, being a peculiar aromatic principle, soluble in
alcohol and water. By heating it, or by combustion, it evolves a very
agreeable smell, and is, therefore, used in those fire-works which
are exhibited in rooms, theatres, &c. and also in the composition
of odoriferous fire-works. Besides being in itself inflammable, it
produces a peculiar smell, arising, in all probability, from an
essential oil, aided, in some degree, by the separation of benzoic
acid.
It has been examined by Bucholz and Brande. Its general properties
are: that it is insoluble in water, although hot water takes up a
part of it, said to be the benzoic acid. It is soluble in alcohol,
from which it is separated by muriatic and acetic acids, but not by
the alkalies. It is also soluble in ether.
The benzoic acid, or flowers of benzoin, are obtained from it by
sublimation. A quantity of the powdered gum, put into an earthen
basin, a thick paper cone being tied round the rim, and heat applied,
the acid will leave the resin, and be condensed on the inner side
of the cone. Bucholz (_Bulletin de Pharmacie_, v. p. 177) has given
a process for obtaining it by means of alcohol, and some others
have been adopted. By boiling four ounces of the gum in powder in
a sufficient quantity of water, with three drachms of carbonate of
soda, the acid will unite with the alkali, and form a benzoate of
soda, which, when filtered and decomposed by sulphuric acid, will
yield the benzoic acid. Five drachms of acid will be thus obtained.
Lime has been used in the same manner as soda, and the acid separated
by the addition of muriatic acid.
Flowers of benzoin may be used in the place of the gum; using,
however, but a small quantity. They will communicate the same odour
to fire as the benzoin. The flowers, or acid of benzoin, are so
inflammable, as to burn, with a clear yellow flame, without the
assistance of a wick. It is soluble in ardent spirits, in oils, and
in melted tallow. The compounds, which it forms with them, are also
inflammable. Benzoic acid is considered to be an oily acid, and
contains, no doubt, a very large proportion of hydrogen.
_Sect. XVII. Of Storax Calamite._
Storax is the most fragrant of all the balsams. It is afforded by
the _styrax officinalis_, a tree which grows in the Levant. It is
sometimes in red tears. Common storax is in large cakes, and brittle
and soft to the touch. This is more fragrant than the other sort,
but is frequently adulterated with saw-dust. It is soluble in
alcohol, and is said to yield some benzoic acid.
Styrax is a different substance; a semi-liquid juice obtained from
the _liquidambar styraciflua_. Its odour is less agreeable than that
of storax calamite. It is used in odoriferous fire, in _pastes_, in
the composition for _scented vases_, and the like.
_Sect. XVIII. Of Essential Oils._
Essential or volatile oils, as well as the raspings of red cedar,
dried rosemary, and other fragrant plants, are all used in the
preparation of odoriferous fire. In some preparations, the _oil of
roses_ is employed; in others, the essence of bergamot, of lemon,
&c. which, being very volatile, evaporate in a moderate heat, and,
being also inflammable, may assist in the combustion. In the case of
the raspings of cedar in particular, it also communicates a peculiar
appearance to the flame.
Oils, whether essential or fixed, when passed through ignited tubes,
are decomposed, and furnish an inflammable gas called olefiant gas.
Wax, tallow, &c. produce the same gas, the hydroguret of carbon.
Messrs. Taylor and Martineau contrived an ingenious apparatus for
generating gas from oil on the great scale, as a substitute for
candles, lamps, and coal gas, it being much preferable for burning,
as it contains no sulphur, and does not injure furniture, books,
plate, paint, &c. Oil gas contains more hydroguret of carbon than
coal gas, which is a great advantage, enabling one cubic foot of
oil gas to go as far as four of coal gas. An elegant apparatus was
erected by Taylor and Martineau at the Apothecaries' Hall, London, a
drawing of which may be seen in the 15th number of the "_Journal of
Science and the Arts_."
It is to be observed, that odoriferous fire-works are intended for
exhibition in close apartments; so that the smell of certain gases,
produced by the nitre, charcoal, and sulphur, according to the
preparation used, will be more or less destroyed. Such preparations
are, nevertheless, expensive, and for that reason seldom used.
_Sect. XIX. Of Mastich._
This resin, obtained, from the _pistacia lentiscus_, by making
transverse incisions in the tree, is first in a fluid state, and
gradually concretes into yellowish semi-transparent brittle grains.
In Turkey, great quantities of it are used for sweetening the
breath, and strengthening the gums. It is from the use of the resin
as a _masticatory_, that its name is said to be derived. It is not
completely soluble in alcohol, a soft elastic substance separating
from the solution. When exposed to heat, it melts, and exhales a
fragrant odour: for which reason, principally, it enters into the
composition of some fire-works, as the _scented paste_. In ordinary
fumigations, mastich is commonly used.
_Sect. XX. Of Copal._
Gum copal, by which name it is known, is a resin, obtained from
a tree, called _thus copallinum_. It is often in the form of a
beautiful white resin; but sometimes it is more or less coloured.
It is frequently opaque. It may be dissolved in alcohol, spirit of
turpentine, and oils, by a peculiar management, (by using camphor,
previously melting it, and the like,) and then it forms the various
copal varnishes, which are more or less perfect, as the copal is
transparent, and the solution properly formed. When heated, it
melts like other resins, and in this, and many other properties, it
partakes of the character of resins in general. It is used in some of
the formulæ for fire-works.
_Sect. XXI. Of Myrrh._
Myrrh is obtained from a plant, supposed to belong to the genus
_mimosa_, which, as Bruce informs us, (_Travels, &c._) grows in
Abyssinia and Arabia. It is in the form of tears, of a reddish-yellow
colour; sometimes transparent, and at other times opaque. It
possesses a peculiar odour, and a bitter and aromatic taste. It burns
with difficulty, and does not melt when heated. With water, it forms
a yellow opaque mixture. It dissolves in alcohol, and the solution
is decomposed by the addition of water, the whole becoming opaque.
According to Braconnot, myrrh is composed of 23 resin, and 77 gum, in
the 100 parts. Pelletier, whose analysis differs from Braconnot's,
observes, that, besides resin, it contains some volatile oil, to
which, no doubt, its fragrance is owing. The gum, extracted from
it, had the character common to all gums, with the exception, that,
instead of forming the mucous or saclactic acid, by the action of
nitric acid, it produced only oxalic acid.
That myrrh burns with difficulty, is owing entirely to the presence
of so much gum, and, comparatively speaking, the small quantity
of resin, which enters into its composition. But, notwithstanding
this property, as it partakes of a fragrant oil, it is used in
some compositions for fire-works. The gummy part may retard, as is
sometimes required in particular preparations, the rapidity of the
combustion, and therefore have a two-fold effect when employed in
fire-works.
_Sect. XXII. Of Sugar._
Refined sugar is sometimes used in pyrotechno-mixtures. As it is a
vegetable oxide, (composed of carbon, hydrogen, and oxygen), which
is decomposed by heat, and has the property of decomposing nitric
acid, and some of its combinations; its operation in such mixtures
may be readily perceived. We have seen, when treating of chlorate
of potassa, that, when this salt and sugar are mixed together, and
sulphuric acid poured on the mixture, a rapid combustion ensues,
which is owing as well to the decomposition of the sugar, as to
that of the salt. The matches, likewise, which inflame by immersion
in sulphuric acid, are covered with a similar mixture. That sugar,
therefore, has the property of decomposing those salts, which are
composed of acids, that have their oxygen but feebly combined,
and thereby producing combustion, according to the temperature
employed, or other agents made use of, is evident from a variety
of experiments. By its action, then, in such cases, the products
of combustion, arising from the elementary parts of the sugar
alone, uniting with oxygen, must be carbonic acid and water. Sugar,
submitted to destructive distillation, affords a variety of new
substances; among which we may notice _caromel_, or that peculiar
odour, which is recognised in the burning of sugar. Sugar may,
therefore, besides assisting in part in the decomposition of saline
bodies, and particularly nitre, and perhaps giving rise to new
products, with which we are unacquainted, have another effect, that
of destroying the offensive smell of other substances, by means of
the caromel formed. Sugar, also, when mixed with various bodies, and
struck with a hammer, will produce detonations.
Sugar, when used in compositions of fire, should be pure; and it may
be known to be so, by producing invariably a phosphorescence in the
dark, when two pieces are rubbed together. At a red heat, it bursts
into flame with a kind of explosion. This flame is white, with blue
edges.
Sugar is obtained from the sugar-cane; from the sap of the
sugar-maple; from beets and grapes; and from various other saccharine
bodies. It is formed also artificially, by the action of sulphuric
acid on starch.
Mr. Kirchoff, a Russian chemist, accidentally discovered that starch
may be changed into sugar by diluted sulphuric acid. One hundred
parts of starch yield one hundred and ten of sugar. It appears, that,
by the abstraction of a little hydrogen and carbon, starch will be
converted into sugar. Potatoes, digested with diluted sulphuric
acid, Dr. Ure found, would also form sugar, and very abundantly.
The sulphuric acid may be removed by the addition of chalk, and, as
the sulphate of lime is but slightly soluble, the pure saccharine
fluid may be obtained by filtration. The sugar is procured in a
solid state by evaporation, and may be clarified like other sugar.
Dr. Ure observes, that good beer has been made from starch-sugar,
but recommends potato-sugar. To obtain the latter, the potatoes are
washed, grated down, and treated with the dilute acid for a day or
two, at a temperature of 212°.
The observations of Braconnot are interesting. He has succeeded in
converting a variety of vegetable substances into gum and sugar. The
conversion of wood into sugar, however remarkable it may seem, has
been effected; and a pound weight of rags will, by the same process,
make more than a pound weight of sugar. Rice, as it contains a large
quantity of fecula, may, we have no doubt, be converted, in the same
manner, into saccharine matter.
When sugar is first obtained, it is impure, containing a variety
of foreign substances, and more or less brown, as the Muscovado of
the West India islands. It is refined, and formed into loaves, by
treating its solution in water with bullocks' blood, the serum of
which coagulates by heat; and, finally, by pouring the sugar, when
sufficiently boiled, into conical earthen moulds, where it concretes.
It is clayed, by putting a mixture of white clay and water on the
sugar in each of the cones; the water from which passes through, and
renders it beautifully white. The same process may be repeated; hence
the single and double refined sugar. The molasses passes out from the
sugar at the apex of the cone, and is received in vessels.
From twenty to thirty-five per cent. of molasses are separated in the
refining of raw sugars; and it is supposed, that a considerable part
of it, probably two-thirds, are formed by the high heat used in the
concentration of the sirup. In order to prevent so great a quantity
of molasses, different plans have been recommended. That of Howard
is highly spoken of. It consists in surrounding the sugar-boiler
with oil or steam at a high temperature, instead of exposing it,
as heretofore, or the mode usually adopted, to the naked fire. The
boiler is covered at top, and, by means of an air-pump, the air
is exhausted, and the pressure of the atmosphere being removed,
ebullition takes place at a lower temperature. No blood is used in
Mr. H.'s process, instead of which, the clarification is performed by
means of canvass filters, adding previously a pasty mixture of gypsum
and alumina, made by saturating a solution of alum with quicklime.
He does not employ clay, as is done in whitening the sugar; but,
in its place, makes use of very pure saturated sirup. He uses
animal charcoal, (bone black), which has the property of destroying
vegetable colouring matter. Wilson's process for refining sugar
possesses some advantages. It will be found in the 34th volume of the
_Repertory of Arts_. The patent filtering apparatus of Sutherland is
highly approved.
The chemical properties of sugar are the following: It is very
soluble in water, both hot and cold; it forms with water a sirup,
which on standing will crystallize, forming the candied sugar. It
is not acted upon by oxygen gas. It is capable of combining with,
and, according to some chemists, of neutralizing acids and alkalies.
It is decomposed by nitric acid with effervescence, being converted
into oxalic and malic acids. Tartaric, acetic, and oxalic acids
prevent it from crystallizing. It unites with lime and strontian,
but is partially decomposed by barytes. It combines also with oxide
of lead, which it precipitates from its solution, forming, as it
is called, a saccharate of lead. Alcohol has some action on it,
and also hydrosulphurets, sulphurets, and phosphurets of alkalies
and alkaline earths. On the application of heat, it melts, swells,
becomes brownish-black, and exhales a peculiar odour, which we have
mentioned, and, at a red heat, takes fire. Lastly, though possessed
of some general and specific characters, it differs, in some of its
properties, according to the substance from which it is obtained.
_Sect. XXIII. Of Sal Prunelle._
This salt is nothing more than nitrate of potassa, melted in a
crucible, and poured into moulds, whence it receives the form under
which it is found in the shops. The saltpetre, when merely fused,
is not decomposed, as it is when exposed to a red heat in an iron
retort. In the former case, the water only which it contains is
separated; but, in the latter, the salt itself is decomposed, and
oxygen gas evolved. Sal prunelle, therefore, is fused saltpetre.
Combustible bodies, as charcoal, sulphur, phosphorus, oils,
resins, &c. have the same effect on it as on ordinary nitre. The
only advantage it has over the common refined saltpetre, in the
preparation of some fire-works, is, that it is free from water, and
more readily acted on by combustible substances. In preparing it,
care must be taken in the application of the heat; which, if too
powerful, would, besides fusing it, decompose, and convert it into
nitrite of potassa. It may be readily pulverized and sifted. For the
properties of _nitre_, see that article.
_Sect. XXIV. Of Alcohol._
Alcohol, or rectified spirit of wine, is used for a variety of
purposes in pyrotechny, and, when it cannot be procured, strong
brandy is substituted. In assisting the pulverization of some
substances, as camphor, in forming the mixture of certain pastes, and
in acting as a vehicle for the intimate union of some bodies, it is
considered a necessary article. Alcohol may be made to form variously
coloured flames, by mixing with it certain saline substances. Thus,
boracic acid will form a green flame; muriate of strontian, a carmine
red; muriate of lime, an orange; nitrate of copper, an emerald
green; nitre, common salt, and corrosive sublimate, a yellow, &c. As
alcohol has the property of dissolving essential oils, camphor, &c.
it may be used as a menstruum for certain oils in the preparation
of odoriferous fire-works. See _Articles on coloured flame, and
odoriferous fire_.
Alcohol constitutes a part of all ardent spirits, wine, cider,
beer, &c. in which it is combined with water, or with water and
mucilaginous and colouring matter. It is formed in the vinous
fermentation, and always results from the union of carbon and
hydrogen. During the process, carbonic acid gas is liberated.
Fermented liquors, therefore, or those which have passed through
the vinous fermentation, always contain alcohol in more or less
abundance, but mixed with water in many instances. In some it is
accompanied with water, and saccharine, mucilaginous, and extractive
matter. The different kinds of beer is an example of this fact.
When liquors, which contain spirit, are submitted to distillation,
the product is alcohol and water; for the volatile parts evaporate,
and the fixed substances remain in the still. The spirit partakes,
more or less, of a peculiar taste and flavour, by which liquors are
distinguished from each other. On this subject, however, it will be
sufficient to add, that brandy is procured by the distillation of
wine; rum, from the fermented juice of the sugar-cane; gin, from
fermented grain and juniper-berry; whiskey, from the fermented mash
of grain, cider, &c. and, generally, the ardent liquors, from pears,
peaches, and other substances, by the same process.
Alcohol, therefore, exists in all these distilled liquors, in a
greater or smaller quantity, combined with water; and the proportion
it bears to the water is known by a standard, as either proof, above
proof, or under proof, according as its strength is shown by the
hydrometer.
The process of obtaining alcohol in a pure state, (usually called
rectified spirit of wine), by which the water is separated from the
alcohol, consists in repeated distillations, either alone, or mixed
with certain substances, which have the property of uniting with, and
keeping down the water, in the act of distillation. These substances
are usually potash, and dry muriate of lime, both of which substances
have a great affinity for water. The specific gravity of highly
concentrated alcohol, at 60° is .820, but that of common alcohol,
only .837, at the same temperature.
The properties of alcohol are the following: It is a transparent
liquor of an agreeable flavour, and may be changed in this
particular, by essential oils. It may be exposed to a low temperature
without freezing. It boils at 106°, when of the specific gravity
.820, and in a vacuum at 56°. It has a strong affinity for water,
with which it combines in any proportion; and the specific
gravity varies according to the proportion of the mixture and the
temperature, on which are founded the tables of Blagden, Gilpin, and
others.
Neither common air, nor oxygen, has any action on alcohol at moderate
temperatures, whether in a liquid or aeriform state. On hydrogen,
carbon, and charcoal, it has little or no action, but on phosphorus
it acts, a portion of which it dissolves. With sulphur, it may be
made to unite, as also with the alkalies, but not with the earths,
except strontian and barytes. It is decomposed by sulphuric and
nitric acids, with both of which it forms ether. It dissolves some
salts, and has scarcely any effect upon others. Lastly, it dissolves
resins and essential oils; but it neither acts upon gums, properly so
called, nor on fixed oils. It is a compound of hydrogen, carbon, and
a small proportion of oxygen, and may be decomposed, by passing its
vapour through an ignited porcelain tube.
Alcohol, by its combustion, as it is used in spirit-lamps for
chemical and other purposes, produces no smoke, in consequence of
the carbon it contains being totally converted, during that process,
into carbonic acid; and its hydrogen, uniting with another portion of
the oxygen of the atmospheric air, passes off in the form of aqueous
vapour. Alcohol, used in this way, is preferable to oil; for the
latter produces a large quantity of smoke, unless it is burnt in the
Argand lamp. Alcohol is inflamed, when it is brought in contact with
an ignited body. The combustion is rapid without any residue, and the
flame white.
As to the strength of alcohol, the best means of determining it, is
with the hydrometer; but usually its _proof_ is ascertained by means
of gunpowder. A portion of powder, put into a cup, and alcohol poured
on it and inflamed, will, if the latter be strong, be set on fire;
if, however, the powder should not take fire, but the flame of the
alcohol be extinguished, we infer the existence of water, and that
the alcohol is not of the proper strength. This experiment is founded
on this circumstance, that, if the alcohol contains water, after the
alcoholic portion is all consumed, the water will not only extinguish
the flame, but also prevent the inflammation of the powder. The
hydrometer, however, is the best experiment, as it determines at once
the fact of the _strength_ of the liquor.
Alcohol is used in the preparation of certain fulminating substances,
as fulminating mercury and silver in particular; the preparation of
which, we will give in the two next sections.
It may not be improper to mention another application of alcohol,
that of forming the _aphlogistic lamp_, or lamp that burns without
flame. The following description of it, is given by Accum, in his
_Chemical Amusements_, Am. Ed. p. 355. "In a common lamp, with a
wick of about half a dozen common threads of cotton wick, used for
lamps, put some good spirit of wine. Dispose the threads of wick, not
intertwined, but straight and parallel to each other. Take platina
wire of the thickness of 1/100th part of an inch; coil it round the
wick, about nine coils below, and six coils standing above the top
of the wick; the diameter or width of the coils should not be more
than 3/20th, or 1/7th of an inch wide. Light the wick; and, when the
coil of platina above the wick is red-hot, blow out the flame. There
will then be a current of pure alcohol, gradually rising from the
reservoir below, through the wick, sufficient to keep the upper coil
of platina red-hot, until the whole of the alcohol is consumed. This
lamp has kept constantly lighted during sixty hours. By means of
it, a match, a bit of spunk, or candle may be lighted when wanted.
The quantity of alcohol consumed is not much: about an ounce, or an
ounce and a half during the night, from bed-time until morning will
suffice." This article was added to Accum by Dr. Cooper. A figure
of the lamp is in Brande's Chemistry. Dr. Comstock has a paper on
the aphlogistic or flameless lamp, in Vol. IV. p. 328, of Silliman's
_Journal of Science and Arts_, which contains some judicious and
useful remarks. Sir H. Davy (_Journal of the Royal Institution_) has
discovered, that the vapour of camphor answers the same purpose as
alcohol. If a platinum wire be heated and laid upon camphor, it will
continue to glow as long as any remains, and the wire will frequently
light it up into flame. Davy found, that, in the slow combustion of
alcohol, &c. an acid was generated, to which he gave the name of
Lampic acid. Faraday and Daniel (_Journal of Science and the Arts_)
have confirmed his conclusions.
Dr. Marcet has proposed a method of producing an intense heat, by
causing a current of oxygen gas to pass through the flame of alcohol.
The construction of the lamp and gas-holder may be found in the
_Archives des Découvertes_, Vol. vii, p. 61.
_Sect. XXV. Of Fulminating Mercury._
As the fulminating mercury of Howard consists principally of the
oxalate of mercury, the oxalate of this metal may be employed for the
same purpose. Oxalic acid does not act on mercury, but dissolves its
oxide, and forms with it a white powder. I formed various fulminating
metallic powders, (_See Coxe's Medical Museum_), and prepared one
in particular by merely digesting a solution of the salt of sorrel
(superoxalate of potassa) on red precipitate. The effect is that the
oxalic acid unites with the oxide of mercury, and forms an oxalate
of mercury, which, when struck with a hammer, produces a detonation.
Oxalate of mercury, possessing the same effects, may be formed, very
expeditiously, by pouring the oxalate, or the superoxalate of potassa
into a solution of nitrate of mercury. The oxalate of mercury will be
precipitated, which is to be caught on a filter, washed, and dried in
a gentle heat.
Howard's fulminating mercury is less dangerous than either
fulminating silver, or fulminating gold. The extreme force of
detonation which it possesses is remarkable. The temperature
required for its explosion is 360 degrees. Friction, percussion,
electricity, and the flint and steel will produce this effect. It
gives rise to a stunning disagreeable report, and its force is
sufficient to indent both the hammer and the anvil. Four or six
grains are sufficient for an experiment. It is rather singular, as
Mr. Cruikshank first observed, that this powder will not inflame
gunpowder; as may be shown by spreading some of the former on paper,
and shaking gunpowder over it, and then firing the mercurial powder.
The grains of the gunpowder may be collected entire after the
explosion.
From the experiments of Howard, it appears, that this powder is
composed of oxalate of mercury, and nitrous etherised gas. Fourcroy,
however, has shown, that it varies in its nature, according to the
mode of its preparation.
There is also a preparation of mercury, which is likewise explosive,
discovered by Fourcroy. This compound may be formed by digesting
the red oxide of mercury in liquid ammonia for the space of eight
or ten days. The oxide assumes a white colour, and at last appears
in crystalline scales. Upon ignited coals, it detonates loudly like
fulminating gold, which see below. In a few days, however, it loses
its fulminating property, and undergoes spontaneous decomposition.
Exposed to a low heat, the ammonia is disengaged, and an oxide of
mercury remains.
As ammonia forms several detonating compounds with metallic oxides,
the theory of their explosive effects is the same; viz. that, while
the hydrogen of the ammonia unites with the oxygen of the oxide,
forming water, the azote is disengaged in the state of gas.
The process for preparing Howard's fulminating mercury is the
following, dissolve one hundred grains of mercury in an ounce and a
half (by measure) of common nitric acid, assisting the solution by
heat. When cold, pour the solution upon two ounces (by measure) of
strong alcohol, and apply a moderate heat, until the mixture begins
to effervesce. A white fume then begins to undulate on the surface of
the liquor, and a white powder precipitates, which is the fulminating
mercury. This powder is to be immediately washed with cold water,
and dried at a heat, not much exceeding that of boiling water. One
hundred grains of mercury, will give, on an average, one hundred and
twenty-five grains of the powder.
The products of its combustion are carbonic acid gas, azotic gas,
water, and mercury. Besides by percussion, it is inflammable when
brought in contact with sulphuric acid. It is supposed, that
fulminating mercury sometimes contains ammonia, and that the products
of combustion, according to the mode of preparation, are therefore
different. The reader may consult some interesting observations on
this powder in the _Journal de l'Ecole Polytechnique_.
M. Bayen, an apothecary, in 1779, (_Journal de Physique_), announced
a process for preparing fulminating mercury. His process, however,
is different from that described. A solution of mercury is made in
nitric acid, and precipitated by caustic alkali. The precipitate
(oxide of mercury) is then caught on a filter, washed, and dried.
Thirty grains of this powder, mixed with four or five grains of
sulphur, and struck with a heavy hammer, or heated on an iron, will
explode with violence. The oxide of mercury, obtained from its
solution by lime-water, has the same effect, when treated in the same
manner. Another process recommended is, to precipitate a solution of
the perchloride of mercury (corrosive sublimate) by lime-water, and
treat the precipitate with sulphur, as above described.
_Sect. XXVI. Of Fulminating Silver._
This compound, which is more powerful than fulminating mercury, is
prepared also with alcohol. Descostils (_Annales de Chimie_, LXII. p.
198,) Cruikshank, and Brugnatelli, have all written upon it.
Fulminating silver explodes without much heat. By the slightest
friction it is inflamed, and detonation follows. Hence it is used in
the form of toys, in fulminating balls, bombs, crackers, &c. which
explode by falling on the ground. Torpedoes, pulling crackers, &c.
are formed of this powder. The fulminating balls are made of glass,
and contain a grain or two of fulminating silver, mixed with sand.
The same mixture, put on the ends of two strips of paper, and the
ends pasted, forms the pulling crackers; for the moment they are
pulled asunder, the friction produced sets the fulminating silver on
fire, and causes a detonation.
The same preparation placed on a wafer, and the wafer put between
paper, as in the sealing of a letter, will explode, when the paper
or the wafer is broken. Fulminating bombs are balls of the size of a
hazle nut, containing about three grains of the fulminating silver.
Their explosive effects are said to be violent. See _Detonating
Works_.
This powder, in consequence of its powerful action, is dangerous;
and, as it explodes so readily, it should never be put into a phial,
nor should it be touched or handled in any way that can produce
friction. Even when made to approach the flame of a candle, it will
explode with extreme violence.
The preparation of Brugnatelli's fulminating silver consists in
reducing 100 grains of nitrate of silver (lunar caustic) to powder;
and, when put into a basin, pouring over it one ounce of alcohol,
and the same quantity of nitric acid. The mixture will become hot,
effervescence will ensue, while the whole will assume an opaque or
milky appearance.
When the gray powder of the nitrate has become white, and the mixture
acquires consistency, distilled water is to be added, to suspend
the action. The white precipitate is then to be washed by repeated
affusions of cold water, and dried in the open air, but in a dark
place, so as to seclude it from the light.
In fact, this process is similar to that for preparing fulminating
mercury; for it is nothing more than treating silver with nitric acid
and alcohol. Cruikshank employs forty parts of silver, sixty parts of
nitric acid, and sixty parts of alcohol, from which sixty parts of
the powder are obtained.
Berthollet considers this powder to be composed of ammonia, and oxide
of silver, and the theory of its detonation to be the same as that
of fulminating gold. In its explosion, the oxygen of the oxide of
silver unites with the hydrogen of the ammonia, and the nitrogen is
disengaged.
Berthollet's fulminating silver, which he discovered in 1788, is
another preparation, which fulminates powerfully. It is prepared by
precipitating nitrate of silver by lime-water. The precipitate is
placed on filtering paper, which absorbs the water, and the nitrate
of lime. Pure caustic ammonia is then added, which produces an effect
somewhat similar to that attending the slaking of lime. The ammonia
dissolves only a part of this precipitate. It is left at rest for ten
or twelve hours, and at the expiration of this time, there is formed,
on the surface, a shining pellicle, which is re-dissolved with a
new portion of ammonia, but which does not appear, if a sufficient
quantity of ammonia has been added at the first. The liquid is then
separated, and the black precipitate, found at the bottom, is put, in
small quantities, on separate papers. This powder explodes even when
moist, if struck with a hard body. When dry, the slightest friction
will explode it. Its detonation is owing to the same cause as that
producing the explosion of the other preparation of this metal, as it
is also composed of oxide of silver and ammonia.
The fulminating silver of Chenevix explodes only by a slight
friction in contact with combustible substances. It is nothing more
than chlorate of silver. It is formed by passing chlorine gas through
alumina, diffused in water, and afterwards digesting, in the liquor,
some phosphate of silver. The whole is to be evaporated slowly. A
single grain of this powder, with three grains of sulphur, will
explode by the slightest friction.
For the preparation of fulminating silver, the formula given
by professor Silliman of Yale College, appears to possess some
advantages. To an ounce of alcohol and as much nitric acid, he adds
100 grains of pulverized lunar caustic. A gentle heat is applied to
excite the action between them, which must be removed, the moment
they begin to act. When a thick white precipitate appears, cold water
must be added to check the action. The precipitate is then to be
collected, washed, and carefully dried. A grain or two will explode
over a candle.
_Sect. XXVII. Of Fulminating Gold._
The preparation, called by some aurate of ammonia, is formed by
dissolving gold in nitromuriatic acid, diluting the solution with
water, and adding gradually liquid ammonia, until the precipitation
ceases. The precipitate is then to be caught on a filter, well
washed with water, and dried in the air. The fulminating gold,
thus produced, exceeds the weight of the original gold employed by
thirty-three per cent.
Three or four grains of this powder, heated on a knife, will explode
with a loud report. The temperature required for its explosion
is between 230° and 300°. Ten or twelve grains will penetrate a
copper-plate, of the thickness of a playing card. The facility with
which this powder explodes, is increased by drying. If it be heated
until it becomes black, the slightest touch will cause a detonation.
This powder is composed of oxide of gold, ammonia, and a portion of
chlorine; and, during its detonation, water, nitrogen and chlorine
are evolved, the gold being revived.
The presence of ammonia is necessary to give to gold the property of
fulminating. Fulminating gold accordingly loses this property, the
moment the ammonia is separated. Concentrated sulphuric acid, melted
sulphur, fat oils, and ether have this effect.
The discoverer of fulminating gold was a German Benedictine Monk,
who lived about the year 1413. Basil Valentine has described the
preparation of it very accurately. He recommends, however, mixing
sal ammoniac with aqua fortis, the old mode of making aqua regia,
and distilling the mixture; then putting in the gold in leaf. After
the acid is saturated, he adds _oleum tartari_, or _sal tartari_
(carbonate of potassa) dissolved in water; and the precipitated
_calx_, thus obtained, when collected, washed, and dried in the
open air, will fulminate. In this process, it is evident, that the
aqua regia, prepared with sal ammoniac, contains ammonia, and, when
the gold is dissolved, and the potash added, the oxide of gold
separates, and, from the composition of the powder, must combine with
a portion of ammonia, and hence produce fulminating gold. He remarks,
that distilled vinegar digested on fulminating gold, destroys its
fulminating properties, and observes also, that care must be taken to
prevent its explosion. He also knew that sulphur would have the same
effect.
Bergman (_Treatise on Pulvis Fulminans_) describes the process
employed by Valentine; and Beckman (_History of Inventions_, v. iii.
p. 132,) observes, that, after the time of Valentine, Crollius, who
lived in the last half of the 16th century, was well acquainted with
fulminating gold, and made its preparation more generally known.
In the _Oswaldi Crollii Basilica Chymica_, 4to, p. 211, published
at Frankfort, in 1609, the process is also to be found. He calls
it _aurum volatile_, and speaks of its being useful in medicine.
Beguin, however, appears to have given it the appellation of _aurum
fulminans_, if we judge from his _Tyrocinium Chymicum_, 12mo, printed
in 1608.
_Sect. XXVIII. Of Fulminating Platinum._
While noticing explosive compounds, it may not be improper to mention
that of platinum, lately discovered by Mr. E. Davy. It explodes,
when heated to 400 degrees, with a sharp report, similar to that
produced by fulminating gold; but neither friction nor percussion
will decompose it. It is formed by making a solution of platinum in
nitromuriatic acid, and passing through it, sulphuretted hydrogen
gas, until no further precipitation ensues. This precipitate, when
collected, and digested in nitric acid, is converted into sulphate of
platinum. This is dissolved in water, and liquid ammonia then added.
The precipitate, now formed, is washed, and boiled in a solution of
potassa, and, after having freed it from the adhering potassa, is
suffered to dry. All fulminating ammoniacal compounds are analogous;
and fulminating platinum, being composed of oxide of platinum,
ammonia, and water, is decomposed in the same manner as these
compounds.
Fulminating platinum is composed as follows:
Peroxide of platinum 82.5 _nearly_ 2 primes.
Ammonia 9.0 1 ----
Water 8.5 2 ----
_Sect. XXIX. Of Detonating Powder from Indigo._
That indigo produces a detonating powder by treating it with nitric
acid, is evident from experiment. As it produces a _purple_ light, it
might, perhaps, be used advantageously in small fire-works.
The process described by Dr. Thomson, (_System of Chemistry_, VOL.
IV. p. 80, _Amer. edit._) is to boil one part of indigo in four parts
of nitric acid. The solution will become yellow, and a resinous
matter appear upon its surface. The boiling is to be stopt, and the
liquor cooled. The resinous matter is then to be separated; and
the solution evaporated to the consistence of honey. This is to be
re-dissolved in hot water, and filtered, and a solution of potassa
added, which will throw down yellow spicular crystals, consisting of
_bitter principle_, combined with potassa. When the resin is again
treated with nitric acid, the same bitter principle is produced.
The spicular crystals, when wrapped up in paper, and struck with a
hammer, detonate with a purple light.
_Sect. XXX. Of the Fulminating Compound, called Iodide of Azote._
Iodine is a particular substance, which has the property not only
of combining with oxygen and hydrogen, forming iodic and hydriodic
acid, but also with various bases constituting a class of bodies,
called iodides. Its union with azote produces a singular substance,
which detonates with great violence, when slightly touched or heated.
It may be formed, by putting a quantity of iodine into the water of
ammonia. It will be gradually converted into a brownish-black matter,
which is the iodide of azote. It is formed in this process by the
iodine, in the first instance, decomposing a part of the ammonia; the
hydrogen of which combines with a portion of the iodine, and produces
hydriodic acid, which then unites with the undecomposed part of the
ammonia, and forms the hydriodate of ammonia; whilst the azote the
other constituent of the ammonia, unites with another portion of the
iodine, and forms the compound in question.
When exposed to the air, iodide of azote gradually flies off in
vapour, without leaving any residue. The products of its detonation
are iodine and azotic gas.
The iodide of azote was discovered by M. Courtois, and subsequently
examined by M. Colin. Iodine, brought in contact with ammoniacal gas,
a combination taking place, produces a viscid shining liquid of a
brownish-black colour, which, as the saturation goes on, loses its
lustre.
This liquid does not detonate, and is considered to be an iodide of
ammonia; but, when it is added to water, it is decomposed, as well as
the water, and we obtain two new compounds, as before observed, the
hydriodate of ammonia, and iodide of azote. This iodide detonates.
Hence it is evident, that hydrogen united with azote, in ammonia,
prevents explosion; for the moment it is taken away, by the formation
of hydriodic acid, and the azote itself combines with the iodine,
a fulminating compound is formed. The elements of this powder are
feebly united.
It is found, that hydriodate of ammonia has the property of
dissolving a large quantity of iodine, and, if suffered to remain
with the iodide of azote, of decomposing it also, and setting the
azote at liberty. Water is said to have the same effect, although
feebly.
Iodate of potassa, a salt composed of iodic acid and potassa, when
mixed with sulphur, and struck with a hammer, will detonate, in
consequence of the decomposition of the iodic acid. The iodate
of potassa may be formed very readily by agitating iodine with
a solution of caustic potassa. The water is decomposed, and the
hydriodate of potassa is also formed, which, being very soluble,
remains in solution, whilst the iodate separates, on concentrating
the liquor, and suffering it to stand.
Chlorate, as well as nitrate of silver, form with sulphur fulminating
powders.
Iodic acid, called also oxy-iodine, (prepared by exposing iodine to
the action of euchlorine,) when heated in contact with inflammable
substances, and the more combustible metals, will produce detonations.
It appears, however, that sulphur has a stronger affinity for oxygen
than iodine has, and iodine a stronger affinity than chlorine for
the same element. Hence chloric acid is more readily decomposed
by inflammable bodies than iodic acid, and iodic acid, sooner than
sulphuric acid.
The acids, which chlorine, iodine, and sulphur form respectively
with oxygen, Gay-Lussac remarks, have their elements more strongly
_condensed_, than the same substances united with hydrogen.
_Sect. XXXI. Of Detonating Oil, or Chloride of Azote._
This oil is produced by the action of chlorine on ammonia, by using
some of the salts of this alkali. A small jar of chlorine gas is
transferred into a basin, containing a solution of nitrate or muriate
of ammonia, a little heated: an absorption will gradually take
place, and the gas be condensed. An _oily film_ will now appear on
the surface of the ammoniacal solution, which, as it increases, will
form globules and fall through the liquor. This substance is the
detonating oil, composed, according to analysis, of chlorine, azote,
and hydrogen. It is supposed by Messrs. Wilson, Porret, and Kirk,
that the hydrogen serves as a medium of union between the chlorine
and azote, and that, in detonation, the powerful effect is owing to
the chlorine.
Detonating oil explodes violently at 212 degrees; and even when
touched with cold inflammable substances, as a portion of olive oil,
about the size of a pin's head, the detonation is also violent, and
the vessel, in which the experiment is made, will, in most cases, be
broken into fragments.
Detonating oil is considered, however, a chloride of azote. In order
to prevent the decomposition of the chloride by the ammoniacal salt,
a thin stratum of muriate of soda, put into the bottom of the vessel,
is recommended. Its specific gravity is 1.653. Warm water, put into
a vessel containing it, will change it to an aeriform fluid of an
orange colour. "I attempted," says Sir H. Davy, "to collect the
products of the new substances, by applying the heat of a spirit-lamp
to a globule of it, confined in a curved glass tube over water: a
little gas was at first extricated; but, long before the water had
attained the temperature of ebullition, a violent flash of light was
perceived, with a sharp report; the tube and glass were broken into
small fragments, and I received a severe wound in the transparent
cornea of the eye, which has produced a considerable inflammation of
the eye, and obliges me to make this communication by an amanuensis.
This experiment proves what _extreme_ caution is necessary in
operating on this substance; for the quantity I used was scarcely as
large as a grain of mustard seed." _Phil. Trans._ 1813, Part I.
In _vacuo_, it expands into vapour, which still possesses the power
of exploding by heat. In water, it gradually disappears, the water
becoming acid, and azote being evolved. Mercury decomposes it, and a
white powder (calomel) is formed, while the azote is set at liberty.
Dr. Ure (_Chemical Dictionary_, Art. _Nitrogen_,) observes, that the
mechanical force of this compound, seems superior to that of any
other known substance, not even excepting the ammoniacal fulminating
silver. The velocity of its action appears to be likewise greater.
The Doctor touched a minute globule of it, in a platina spoon,
resting on a table, with a fragment of phosphorus at the point of a
pen-knife, and the blade was instantly shivered into fragments by the
explosion.
Messrs. Porret, Wilson, and Kirk (_Nicholson's Journal_, Vol. XXXIV,)
employed 125 different substances, by bringing them in contact; and
out of that number the following caused it to explode:
Supersulphuretted hydrogen,
Phosphorus,
Phosphuret of lime,
Phosphuretted camphor,
Camphoretted oil,
Phosphuretted hydrogen gas,
Caoutchouc,
Myrrh,
Palm oil,
Ambergris,
Whale oil,
Linseed oil,
Aqueous ammonia,
Olive oil,
Sulphuretted oil,
Oil of Turpentine,
---- Tar,
---- Amber,
---- Petroleum,
---- Orange peel,
Naphtha,
Soap of silver,
---- Mercury,
---- Copper,
---- Lead,
---- Manganese,
Fused Potassa,
Nitrous gas.
See _Detonating Works_.
According to Mr. Davy, chloride of azote contains
4 vols. of chlorine = 10 + } or { 4 primes = 18.0 +
1 ---- azote = 0.9722 } { 1 ---- = 1.75,
or very nearly 10 by weight of chlorine to 1 of azote.
_Sect. XXXII. Of Pyrophorus._
Pyrophorus is a black substance, which takes fire spontaneously, when
brought into contact with air. It is the luft-zunder, or air-tinder
of the Germans. It first emits sulphuretted hydrogen gas, and in a
few seconds becomes red-hot, burning with a bluish flame. Pyrophorus
consists of alumina, charcoal, and sulphuret of potassa, and also,
according to some, of potassium, which is alleged to be formed in its
preparation. Be this as it may, it seems, that water is decomposed in
its combustion, that sulphuretted hydrogen gas is emitted, which is
inflamed by the oxygen gas of the atmosphere, and that, during the
combination of oxygen, a degree of heat is produced, which causes
the ignition of the charcoal, as well as the inflammation of the
remaining sulphur.
Pyrophorus may be formed in several ways, all of which produce the
same result. The usual process is the following: Take equal parts of
brown sugar and alum, and melt them in a ladle. Continue the heat,
stirring them constantly until a spongy black mass is formed. Let
this mass be reduced at once to powder, and introduced into a common
green glass phial, of the capacity of about six ounces, previously
coated outside with a mixture of pipe-clay and solution of borax.
Immerse the phial in a crucible, filled with sand, closing the mouth
of the former with a piece of charcoal, or a glass tube inserted in
it. Upon the crucible being exposed to a red heat, an inflammable
gas will escape, which will take fire.[21] When this effect ensues,
the heat must be continued for about twenty minutes longer, at the
expiration of which time, the crucible must be removed from the fire,
and the phial taken out and closely stopt. The pyrophorus is to be
preserved in a ground stoppered bottle. The addition of one-sixteenth
part of sulphate of soda, or Glauber's salt, to the alum and sugar,
is said to make the pyrophorus with more certainty. Various vegetable
substances, besides sugar, as flour, starch, &c. may be used.
Three parts of alum, and one part of wheat flour will make a good
pyrophorus.
Homberg discovered this substance, in the year 1680. Hence it is
sometimes called Homberg's pyrophorus. He was operating upon a
mixture of human excrement and alum; and, when he examined the
contents of his vessel, in three or four days after, he was surprised
to see it take fire spontaneously, when brought to the air. Soon
after Lemery, the younger, discovered, that honey, sugar, flour,
or almost any animal or vegetable matter, could be used in lieu of
human fæces; and, as Macquer informs us, M. Lejoy de Suvigny showed,
that other salts, containing sulphuric acid, may be substituted for
alum. Mr. Scheele (_Treatise on fire_, &c.) found by experiment,
that, when alum was deprived of potassa, it was incapable of forming
pyrophorus, and that vitriolated tartar (sulphate of potassa) may be
used in the place of alum. The experiments of Mr. Proust prove, that
a number of neutral salts, composed of vegetable acids and earths,
when submitted to heat, leave a residuum that inflames spontaneously.
This statement agrees with the experiments of M. Chenevix. From the
experiments and observations of sir H. Davy, and Dr. J. R. Coxe,
late professor of chemistry, but now of materia medica, &c. in the
University of Pennsylvania, it is rendered very probable, that
pyrophorus owes its property of inflaming spontaneously to a small
portion of potassium, which is formed in the process.
The preparation of pyrophorus is explained on the principle, that the
vegetable matter is first decomposed; that the hydrogen and a part
of the carbon decompose the sulphuric acid of the alum, by uniting
with its oxygen; that water, carbonic oxide, and carburetted hydrogen
are disengaged, along with a part of the sulphur; and that, while
the excess of charcoal remains intimately mixed or divided with the
alumina, the sulphur and the sulphuret of potassa, form together a
compound, which has the property of inflaming spontaneously in the
open air. Some suppose, as alum is a triple salt, having potassa, as
well as alumina, for its base, that the potassa is decomposed in the
process, and potassium, as we remarked, produced; to the presence of
which they ascribe the singular property of inflaming in the open air.
The spontaneous combustion of charcoal, in several instances, is
supposed by some to have been owing to the presence of pyrophorus, by
others to phosphorus, and by others again to nascent hydrogen. To the
presence of this substance, is attributed the explosion of gunpowder
mills. (See _Gunpowder_.)
Several different mixtures, and torrefied substances, form a kind of
imperfect pyrophori, and have more than once occasioned fires, from
no suspicion of their properties being entertained.
Besides pyrophorus, other compositions, which, in like manner, take
fire on exposure to the open air, have been by degrees made known to
us: 1. The scoria of the martial regulus of antimony, or antimony
freed from sulphur by the intervention of iron and nitre, as well
crude as also after being dissolved, have been observed to take fire
spontaneously, when laid upon a hot stone, or in the sun. Of the
truth of the latter case, Wiegleb says, he is assured by his own
experience. 2. The residuum of the acetate of copper is another
pyrophorus. 3. Some assert, that they have observed an inflammation
ensue from honey and flour, calcined according to the rules laid
down. 4. According to Geoffroy, a calcined mass of three parts of
black soap, and one of diaphoretic antimony, has been known to take
fire spontaneously. 5. Meuder has observed, that a pyrophorus is
obtained, when equal parts of orpiment and iron-filings are sublimed
together, and ten parts of this sublimate are triturated in a mortar
along with twelve of nitrate of silver. 6. A pyrophorus is produced,
according to Penzky, when two drachms of white sand, three of common
salt, one of sulphur, two of sulphuric acid, and half an ounce of
muriatic, are mixed together and distilled in a glass retort. In
this operation, a sublimate is said to be obtained, which bursts
out in flames, as soon as it comes into contact with the air. 7.
The spontaneous precipitate of osteocolla, from a solution of it in
sulphuric acid, after having been separated by means of a filter,
and dried, took fire in a warm place. S. Pott observed the same
phenomenon in the earth of the residuum, after the distillation of
urine, that had been putrid for a considerable time. 9. To these
may also be referred, a mass composed of equal parts of sulphur and
iron-filings; which, when thoroughly moistened with water, after some
time, grows hot, swells, and at last breaks out into vapour, smoke,
and flame. (See _Artificial Volcano_.)
Cadet's fuming liquor, prepared by distilling equal parts of acetate
of potassa, and arsenious acid, emits a very dense, heavy, fetid,
noxious vapour, which inflames spontaneously in the open air. Black
wadd, an ore of manganese, when dried by the fire, and mixed with
linseed oil, gradually becomes hot, swells, and then bursts into
flame.
M. Chenevix (_Annales de Chimie_, tom. LXIX,) remarks that almost
all the metallic residuums, which are formed by the distillation
of acetates _per se_, are pyrophoric, after cooling; which Mr. C.
attributes to the presence of finely divided charcoal, mixed with the
metallic part. He experimented on several acetates, with the view
of ascertaining the quantity of pyroacetic spirit they would yield,
and found, in every instance, that charcoal existed in the residue,
sometimes with reduced metal, and at other times with metallic
oxide. A table of these experiments may be seen in Ure's _Chemical
Dictionary_. The residuum of acetate of copper has long been known to
possess pyrophoric properties.
_Sect. XXXIII. Of Sal Ammoniac._
This salt enters into the composition of fire-works, to give, more
particularly, a peculiar colour to flame, which is that of green, or
yellowish-green. Sal ammoniac is a salt, composed of muriatic acid
and ammonia, and, when pure, is white, and capable of being sublimed
without decomposition. Its purity may be known by its complete
volatilization. It is readily pulverized.
The experiment, showing the formation of sal ammoniac by a direct
union of its component parts, may be made by bringing in contact, in
a glass receiver, muriatic acid gas and ammoniacal gas. White clouds
will form, a condensation take place, and muriate of ammonia be
deposited on the sides of the vessel.
Sal ammoniac was altogether made, at one period, from the soot of
camels' dung, or of other animals, which feed on saline plants. The
excrement was burnt, the soot collected, and sublimed. This was the
process practised in Egypt. The composition of sal ammoniac being
known, the process for obtaining it was improved; so that, instead
of using the soot of dung, it is now formed by the distillation of
bones. The impure ammoniacal liquor, thus obtained, is combined with
sulphuric acid, by an easy process, and the resulting sulphate of
ammonia is then decomposed by muriate of soda, by which sulphate of
soda and muriate of ammonia are produced. They are separated, and the
latter is formed into heads by sublimation. In this state, it occurs
in commerce. It was made in great quantity in the vicinity of the
temple of Jupiter Ammon; and hence its name.
Mr. Minish, according to the English writers, is entitled to this
method of converting impure liquid ammonia into sal ammoniac. The
following is an outline of his process. He suffered the impure
ammoniacal liquor to percolate through a stratum of bruised gypsum,
and as carbonate of ammonia is contained in the liquor, the fluid,
which filters, would contain sulphate of ammonia, the carbonate
of lime being insoluble. This sulphate he evaporated, and the dry
mass, mixed with muriate of soda, was sublimed. If I am not greatly
mistaken, however, although I have not the work to refer to, this
process is described in Dr. John Pennington's _Chemical Essays_, a
work published in Philadelphia, about 1792. Dr. Pennington's work,
we may observe, is the first chemical book which was published
in the United States, and contains numerous important facts and
observations. That this process was known in Philadelphia, and used
at the _Globe works_, or rather _Glaub works_, (from the circumstance
that Glauber's salt was made there,) is within the recollection of
many. I heard the late professor Wistar speak of this process, and of
the economy in using gypsum.
Mr. Lebanc (_Annales de Chimie_, vol. XIX.) invented a process, by
which he brought the ammoniacal gas and muriatic acid gas in contact,
in a chamber lined with lead. In one pot, he put common salt and oil
of vitriol; in another pot, animal matter. Being conducted by pipes
into the chamber, the gases united, and sal ammoniac was formed.
Other improvements have been made, as obtaining ammonia from coal
soot, &c.
Ammonia is generated in artificial nitre beds, and is at first united
with nitric acid; which compound is subsequently decomposed, as the
process of putrefaction goes on, by the potassa, calcareous earth,
&c. present in nitre beds. _See Nitrate of Potassa._
Sal ammoniac is ready formed in the soot of animal feces, twenty-six
pounds of which yield six of the salt. According to Siccard, who
published, in 1716, an account of the fabrication of sal ammoniac in
Egypt, which Geoffroy, in the same year, proved to be a compound of
the spirit of sea salt and volatile alkali, sea salt and urine were
used in that country. The account, however, given by Lemery, in 1719,
makes no mention of either sea salt or urine.
Sal ammoniac is found native. It occurs in the vicinity of burning
beds of coal, both in Scotland and England, and is met with in
volcanic countries. When triturated with quicklime, it exhales
ammonia, which is a characteristic of all ammoniacal salts.
Sal ammoniac is often found in crusts of lava. Sir William Hamilton
observes, that, in the fissures formed by the lava, this salt
sublimes. He found, in the same locality, common salt.
Sal ammoniac is decomposed by a variety of substances. Sulphuric
acid will disengage the muriatic acid from it, while lime, potassa,
&c. liberates the ammoniacal gas, which, when combined with water by
distillation or other means, forms the common spirit of sal ammoniac,
or water of ammonia. Mixed with carbonate of lime and sublimed, it
produces the carbonate of ammonia, usually called mild volatile
alkali, or pungent smelling salts. Ammonia, in a separate state,
unites with some metallic oxides, giving rise to certain fulminating
powders, which have been already noticed. That iodine decomposes
ammonia, we have shown, when on the preparation of iodide of azote,
or fulminating powder.
Sal ammoniac enters into the composition of candles, to prolong their
duration. The process recommended in the _Archives des Découvertes_
is the following: Dissolve, in half a pint of water, a quarter of
an ounce of sal ammoniac, two ounces of common salt, and half an
ounce of saltpetre, and add the solution to three pounds of mutton
tallow, and eight pounds of beef tallow, previously melted. Continue
the heat until all the water is evaporated. It is then suffered to
cool, and, when used, is to be melted with a quarter of an ounce of
nitre, and formed into candles in the usual manner. This preparation
of tallow is highly recommended on account of its economy, as well as
the improvement itself. A candle, made of this tallow, will burn two
hours longer than one of the ordinary kind.
Another process for making candles, in which sal ammoniac is used,
is mentioned in the _Annales des Arts et Manufactures, Nos. 142 and
146_. Eight pounds of suet are melted, and a pint of water is added.
The tallow is again submitted to heat, and the same quantity of
water, holding in solution half an ounce of saltpetre, half an ounce
of sal ammoniac, and one ounce of alum, is added. It is then suffered
to stand, and when used is re-melted. The wick is first dipped in a
mixture of camphor and wax. Care must be taken, before the tallow is
used, to evaporate the water. Equal parts of beef and mutton tallow
are recommended.
_Sect. XXXIV. Of Corrosive Sublimate._
Corrosive sublimate, known in chemistry by the names of corrosive
muriate, and perchloride of mercury, is made use of in some
preparations of fire-works, and particularly in the composition
of stars, in which it is mixed with a variety of substances, such
as steel filings and antimony, in order to vary the appearance of
the flame, and to communicate to it particular colours. Corrosive
sublimate is formed by various processes, among which we may
enumerate the following: Take five parts of sulphuric acid, four
parts of mercury, four parts of muriate of soda, and one part of
black oxide of manganese. Boil the mercury in the sulphuric acid,
until it forms a dry sulphate, which is to be reduced to five parts.
Mix the sulphate thus formed, with the muriate of soda, previously
dried, and the oxide of manganese, and sublime the mixture. By this
process the sulphuric acid of the sulphate unites with the soda, and
forms sulphate of soda; while the muriatic acid of the muriate of
soda combines with the oxide of mercury, (which receives an addition
of oxygen from the oxide of manganese,) and forms the perchloride,
called by Thenard the deutochloride of mercury. The same process is
used without the addition of manganese. By exposure to heat, the
sublimate sublimes, and the sulphate of soda forms the residuum.
The same salt, if re-sublimed with an addition of crude mercury,
will be changed into the protochloride of mercury, or calomel. Or,
if the sulphate of mercury and muriate of soda be mixed with crude
mercury, and sublimed, calomel will be formed at one operation. It is
sufficient to observe, that corrosive sublimate is one of the most
virulent of poisons when swallowed; and therefore should be used with
caution.
It is soluble in water, and capable of crystallizing. It is also
soluble in alcohol, to the flame of which it communicates a
yellow colour, and in sulphuric, nitric, and muriatic acids. It
is decomposed by alkalies, forming with ammonia a triple salt,
(_Sal Alembroth_,) by the alkaline earths, and the metals or their
sulphurets; and, when distilled with arsenic, bismuth, antimony, or
tin, the mercury is separated.
The proper antidote for corrosive sublimate, is the white of egg or
albumen, which converts it into calomel. Sulphuretted hydrogen water
may also be employed along with emetics. The effect of albumen, in
this way, may be relied on.
_Sect. XXXV. Of Orpiment._
Orpiment, or the yellow sulphuret of arsenic, which is either native
or artificial, is principally used in fire-works for the composition
of stars. Orpiment is divided by some into two kinds; viz. the red,
called realgar, and the yellow, called yellow arsenic.
Arsenic combines readily with sulphur. When they are mixed together,
and put into a crucible and fused, the product will be a red vitreous
mass. This red sulphuret may also be formed, by melting sulphur with
arsenious, or arsenic acid. Sulphurous acid gas will be evolved,
evidently showing that a portion of the sulphur unites with the
oxygen of acid employed.
When arsenious acid, known in commerce by the name of white arsenic,
and called by some oxide of arsenic, is dissolved in muriatic acid,
and a solution of sulphuretted hydrogen in water is added, a yellow
precipitate will be obtained which is orpiment. The hydrogen, in
this case, unites with the oxygen of the arsenious acid, by which the
metal is reduced, and the sulphur then combines with it. A mixture of
sulphur and arsenic, exposed to a heat not sufficient to melt them,
will sublime into a yellow sulphuret.
Both the yellow and red sulphurets are employed in fire-works. They
are not, however, required, except in particular cases. In the
composition of Bengal lights, given in the Bombardier or Pocket
Gunner, by R. W. Adye, orpiment is used. According to the same
author, it is also used in Chinese white lights. Both the yellow and
red sulphuret of arsenic will detonate with chlorate of potassa.
_Sect. XXXVI. Of Antimony._
The antimony, which enters into the composition of many fire-works,
is not to be understood to be the metallic, or regulus of, antimony,
unless so expressed; but the crude antimony of the shops. Crude
antimony is a combination of antimony and sulphur, and is usually
met with in fine powder. That both antimony and its sulphuret have
a powerful effect in modifying the flame of gunpowder, and all
compositions, in which nitre and inflammable substances form a part,
is evident from the many cases, in which it is employed, and from the
effects that thereby result.
The different substances in any inflammable compound, intended
to produce particular colours, should be so mixed, as that, from
a knowledge of the proportions which produce such colours, the
_effect_ may be retained, even when it is mixed with other bodies.
For this reason, the artist should know the different effect of each
ingredient. Some may show themselves in the flame, some in sparks,
some in stars, others in fire-rain, and the like, as the case may
be. Antimony, for instance, produces a reddish flame, if it be
in a proper proportion, and not altered by the presence of other
substances. Hence, when antimony is mixed with nitre, the flame will
be more or less a _whitish-green_.
This modification, or change in the appearance of flame, is apparent
in certain compounds, of which antimony constitutes a part. Thus,
antimony is used in the preparation of the common rocket stars, in
drove stars, in the fixed pointed stars, in some of the gold and
silver rains, in the slow and dead fire for wheels, in tourbillons
for crowns or globes, in the composition of serpents, lances for
illumination, Bengal lights, and many other kinds of fire-works.
According to Adye, (Pocket Gunner,) it enters into the composition of
carcasses, Chinese lights, &c.
When it is as one to sixteen of nitre, the gunpowder being as four,
and the sulphur, eight, the composition will produce a white flame;
but when it is in the proportion of eight to sixteen of nitre,
without any addition, the flame will be blue. By substituting, in its
place, eight of amber to sixteen of nitre, with sixteen of sulphur,
and eight of meal powder, this change will produce a yellow flame. It
is obvious, however, that these and similar changes are owing to the
proportions, as well as to the substances used.
Antimony, in the state of a sulphuret, when mixed with chlorate of
potassa, &c. will form detonating compounds.
Antimony is a grayish-white metal, more or less brilliant and
laminated. It is brittle, and may be easily reduced to powder. It
melts at a red heat, and evaporates at a higher temperature: on
cooling, it crystallizes. It undergoes no change by exposure to the
air, except the loss of its lustre. When steam is made to pass over
ignited antimony, the decomposition of the water is so rapid, as to
produce a violent detonation. At a white heat, it burns, and forms a
white coloured oxide, called the _argentine flowers of antimony_. Its
oxides are various, some of which, possessing acid properties, are
called acids. The protoxide is gray, the antimonious acid, white, and
antimonic acid, of a straw colour. The crocus of antimony, and the
glass of antimony are oxides of this metal, but in particular states
of combination. It unites with several of the acids. Its oxide, with
tartaric acid, and tartrate of potassa, forms _tartar emetic_. With
chlorine, it constitutes the butter of antimony.
The artificial sulphuret may be formed, by melting sulphur and
antimony together. The native sulphuret is almost the only ore of
antimony, and is the mineral from which the regulus is obtained. It
unites with the metals, forming alloys of different kinds.
_Sect. XXXVII. Of Carbonate of Potassa._
Potassa, either pure or carbonated, retards the progress of
combustion; and, therefore, may prevent, according to the proportion
employed, the action of combustible bodies on nitre. Combustion may
be retarded by using those substances, which are not in themselves
inflammable, and which, if used in too large a quantity, would
effectually prevent it. Clay, wood ashes, &c. as in the blind
fuse, act on this principle; and serve, also, in particular cases,
to produce that succession of explosions, which renders the effect
of some fire-works, more grand and impressive. Rope, soaked in a
solution of saltpetre and dried, would burn rapidly, were it not for
the after immersion in potash ley, or urine, either of which acts by
retarding the progress of combustion. The same thing may be said of
other bodies, the use of which will claim our attention hereafter.
Potassa, although not generally used for the purposes mentioned, as
it is apt to deliquesce, or absorb water, and thus destroy the effect
altogether, may be more advantageously employed in a liquid state, as
in the preparation of slow match in the way stated under that head.
But as match rope is now generally superseded by the port-fire, as a
more certain method of firing cannon, it would be unnecessary, as it
is irrelevant, to enlarge on this head. The use, also, of the priming
fuse, which conveys the fire to the powder in the gun, with certainty
and with rapidity, is an improvement of no small moment.
Alum has also been used for the purpose of checking the rapidity of
combustion, in some particular fire-works. In one of the formulæ
for the preparation of _fire-balls_, to be thrown with the hand,
or fired from a gun, given in the _Memoir on Military Fire-works_,
as taught at Strasburg, in 1764, there is, besides sulphur, mutton
suet, saltpetre, and antimony, _nitre of alum_, equal to one-fourth
of the weight of the compound. That this salt, the supersulphate of
alumina and potassa, is used to make paper, as cartridge paper, &c.
incombustible, is a fact, with which every one is acquainted.
We might, also, enumerate the uses of glue, isinglass, gum arabic,
&c. for similar purposes; and also of wood-ashes, in the composition
of the, so called, blind fuse. Light twisted white rope, when soaked
in strong ley, or a strong solution of potash, we are informed, will
form a slow match that will burn only three feet in six hours.
Potash is obtained from wood-ashes, by lixiviation with water, and
evaporation. It contains more or less impurities; and always carbonic
acid, from which it is separated by quicklime, the alkali being
rendered caustic. Some of the foreign ingredients are burnt off by
exposing it to heat in an oven. It then assumes a white, somewhat
_pearly_ appearance, and takes the name of pearl-ash, but is still
the same alkali.
Wood-ashes, when mixed with quicklime, and lixiviated, produce
caustic ley, the strength of which depends on the quantity of alkali
held in solution. It is this ley, when boiled with oils, fat, &c.
that produces soft soap. Hard soap is a combination of oil or fat,
and soda. The quantity of real alkali in potash may be known by the
proportion of acid required to saturate a given weight of it. Potash,
pearl-ash, salt of tartar, and salt of wormwood are all carbonates
of potassa. This alkali is called the vegetable alkali, because it
is obtained from vegetables. It is considered to be the hydrated
deutoxide of potassium, and when decomposed will furnish potassium.
_Table of the saline or soluble products of one thousand pounds of
ashes of the following vegetables._
SALINE PRODUCTS.
Stalks of Turkey wheat, 198 lbs.
Stalks of sun-flower, 349
Vine branches 162.6
Elm 166
Box 78
Sallow 102
Oak 111
Aspen 61
Beach 219
Fern, cut in August, 116, or 125 according to Wildenheim.
Wormwood 748
Fumitory 360
Heath 115
The observations of Mr. Kirwan on potash may be seen in _Aikin's
Chemical Dictionary_.
When a piece of hydrated potassa is placed between two disks of
platinum, which are brought in contact with the poles of a galvanic
battery, consisting of upwards of 200 pairs of plates, four inches
square, the oxygen will separate at the positive surface, and small
metallic globules of potassium will be formed at the negative
surface. The potassa, in the mean time, will undergo fusion.
Sir H. Davy discovered potassium, in 1807. It may be obtained by
means of iron turnings, in the following manner: Heat the iron
turnings to whiteness in a curved gun barrel, and suffer potassa,
in a state of fusion, to fall upon them very gradually, air being
excluded: potassium will form, and collect in the cool part of the
tube. For the different facts respecting this metal, consult Sir H.
Davy's communications on the subject, and the memoirs of Gay-Lussac
and Thenard, Curadeau, &c. See also, Davy's _Chemical Philosophy_,
and Thenard's _Traité de Chimie_.
Potassa unites with, and neutralizes, acids, and forms salts; the
principal of which are the sulphate, muriate, and nitrate of potassa.
It unites also with sulphur, phosphorus, &c.
Potassa, in the state of carbonate, is very soluble in water, for
which it has so strong an affinity, that, when exposed to the
atmosphere, it deliquesces and becomes fluid. Caustic potassa
undergoes the same change, in a more remarkable degree. It is on
account of its great avidity for water, that the carbonate is used in
the preparation of alcohol from spirituous liquors; it retaining the
water, while the alcohol may be distilled over.
Potassa has a stronger affinity for the acids, than either the earths
or metals; hence it decomposes earthy and metallic salts, the earth
or metallic oxide being precipitated, while it unites with the acid
of the salt. It is on the same principle, that earthy and metallic
salts decompose soap; and waters which are hard, and owe that
property to the presence of earthy salts, will curdle, or, in other
words, decompose soap. Such waters, for this reason, are called hard.
Acids have the same effect in decomposing soap.
The use of potassa is very apparent in the manufacture of saltpetre.
When the nitric acid is combined with an earthy base, as in the
calcareous nitre of the nitre caves of the western country, potassa
from wood-ashes will decompose it, on the principle already stated;
and, by combining with the nitric acid, form nitrate of potassa.
It is used also in refining saltpetre, where earthy salts are
present, besides common salt. The effect of this alkali, for that
purpose, will be more obvious, by referring to the processes for the
extraction and refining of saltpetre, in the article on that subject.
Potassa acts as a flux for siliceous substances and forms glass.
These are its prominent characters.
_Sect. XXXVIII. Of Wood-Ashes._
Wood-ashes, the product of the combustion of wood, contain potassa,
some foreign salts, and earthy and sometimes metallic substances,
insoluble in water. The quantity of alkali, which ashes, obtained
from different woods, furnish, is greater or less, according to
the nature of the wood. The ashes of the oak are generally used in
pyrotechny; but it seems to us, that ashes in common will have the
same effect.
The ashes, for this purpose, should be dry, and passed through a fine
sieve. They enter into the composition of blind fuse.
In some instances, the _leached_, or lixiviated ashes might be used.
The residue, after the separation of alkali and saline matter by
the action of water, is nothing more than the insoluble part of the
ashes. Caustic ley is always obtained from wood-ashes, by mixing them
with about a fiftieth part of quicklime, and putting them into a
barrel or tub, and adding water. The lime takes up the carbonic acid,
and the ley comes off in a caustic state. If the solution should not
contain a sufficient quantity of potassa, or not bear an egg, as
that is the usual criterion of its strength, (which depends on its
specific gravity,) its strength may be increased by evaporation; and,
if too strong, simple dilution with water, is all that is necessary.
While the ashes of some plants, as the upland plants, generally yield
potassa; others, as many marine plants, the _salicornia europea_,
_salsola tragus_, _salsola kali_, _&c._ afford soda by incineration.
It will be sufficient, however, to observe, that the ashes of all
plants contain alkali, in more or less quantity, which depends on
various circumstances; and that the alkali may be extracted by
lixiviation, and, in some instances, may even be seen among the
ashes, in a semivitrified mass. The white ashes, which are formed
by the combustion of animal matter, as osseous or bony substances,
we may remark, do not afford potassa or soda, but only phosphate of
lime, and some uncombined earths. Bones, nevertheless, may, like
wood, be carbonized, although the charcoal formed is of a different
nature. For the preparation of phosphorus from bone-ash, see the
article Phosphorus.
_Sec. XXXIX. Of Clay._
Clay is an argillo-siliceous substance, of a colour more or less
yellow, and containing a variable quantity of silica and alumina,
with oxide of iron. There are a variety of clays; the common potter's
clay, pipe clay, porcelain clay, &c. Some contain, and others are
free from iron. Those that contain this metal burn _red_; while those
which remain, or become white in the process of burning, are free
from it.
The use of clay in fire-works is confined nearly altogether to
rockets. In the driving of sky-rockets, &c. the _charge_ must
always be driven one diameter above the piercer, and on it there is
sometimes rammed one-third of a diameter of clay, through the middle
of which a hole is bored to the composition, so that, when the charge
is burnt to the top, it may communicate its fire through the hole,
to the stars in the head. This, however, is not always the case. See
_Rockets_.
The clay for fire-works, is usually prepared of the common kind,
which contains neither stones nor sand. It must be first baked in an
oven, until perfectly dry, and then pulverized, and sifted through
a common hair sieve. In China, the Chinese mostly employ, for this
purpose, their white porcelain clay.
_Sec. XL. Of Quicklime._
Lime, as it is found in nature, is combined with carbonic and
sulphuric acids, and less frequently with some of the other acids,
as the nitric, fluoric and phosphoric. Calcareous carbonates are the
most abundant; in which we include marble, limestone, and chalk; and
the sulphate, or gypsum, may be considered the next. Lime constitutes
the basis of marine shells; for, when burnt, they furnish quicklime.
Its union with nitric acid is well known, forming the calcareous
nitre of the saltpetre caves of Kentucky, &c. We have mentioned this
combination under the head of nitre.
Without enumerating all the chemical properties of lime, it will be
sufficient to remark, that it is composed of calcium and oxygen,
and, when slaked with water, will evolve caloric in a free state,
while the water solidifies or combines with the lime; that it
forms with water, a solid hydrate, an example of which combination
is afforded by the preparation of mortar; that it dissolves in
water, and forms lime-water, and is slaked by exposure to the air,
absorbing, at the same time, carbonic acid; that it unites with
acids, like other salifiable bases, and forms salts, some of which
are soluble in water, and others not; that it deprives the alkalies
of carbonic acid, and renders them caustic, being itself changed into
a carbonate; and, that it unites with sulphur and phosphorus, forming
a sulphuret and phosphuret, and, also, with hydroguretted sulphur,
and sulphuretted hydrogen, forming a hydroguretted sulphuret, and a
hydro-sulphuret.
When limestone, marble, &c. are burnt in a kiln, the carbonic acid
is expelled, and quicklime formed. Quicklime and lime, chemically
speaking, are synonimous terms.
The fluor, or Derbyshire spar, is a fluate of lime. When this
substance is distilled in a leaden retort, with sulphuric acid,
we have sulphate of lime, and fluoric acid gas, called by some
hydro-fluoric acid. This acid, when received in water, is used to
etch on glass, in the same manner as nitric acid on copper; and while
applied in a liquid state, or in that of gas, it acts on the glass,
by combining with the silicon, and is changed from the hydrofluoric,
into the silicated fluoric acid. If, instead of employing a leaden
vessel, we make use of a glass retort, or introduce powdered glass
or silica, into the leaden vessel, in either case, we obtain another
acid, which we have just mentioned, the silicated fluoric acid; in
consequence of the union of silicon with the supposed radical of the
fluoric acid, known by the name of fluorine.
Quicklime is occasionally, though but rarely, employed in fire-works.
That it increases the strength of powder, is asserted by Dr. Bayne.
See Gunpowder. Its use in making slow match, along with other
substances, is given in the article on that subject.
_Sec. XLI. Of Lapis Calaminaris._
That some of the ores of zinc are employed in fire-works, is evident
from the use of lapis calaminaris, or calamine stone, which is an
impure carbonate of zinc. Calamine should be finely pulverized and
sifted. As zinc gives a particular colour to flame, (see _zinc_),
its carbonate may also communicate a colour, and, under particular
circumstances, may produce a great variety, and, therefore, in
such cases, be preferable to the zinc itself. It is one of the
ingredients in the _dead fire_ for wheels, which is composed of lapis
calaminaris, saltpetre, brimstone, and antimony.
The modifications, to which particular bodies are subject, as to
their respective effects, depend very greatly on the presence of
other bodies, and frequently on the chemical action, which ensues
throughout; so that, as we had occasion to observe, the _effect_
which one body would produce on the flame, maybe completely changed,
modified, or varied by the presence of a second, third, or fourth
substance. The art, therefore, of uniting various bodies, in kind,
as well as in proportion, so as to produce a given effect, can be
acquired only by a series of experiments. Zinc, as a metal, when
finely divided, produces a peculiar effect; when mixed with other
metals, and with certain salts, as sal ammoniac, another; and, when
combined with some acids, as the carbonic in lapis calaminaris, a
third effect; and these effects may be governed, as it appears, by
the presence or absence of certain bodies. This fact will appear
more striking, when we consider the various mixtures, and their
respective properties. For the uses of zinc, see that article.
_Sec. XLII. Of Zinc._
Zinc, commonly called spelter, is a metal, obtained from blende,
or sulphuret of zinc, and calamine, or carbonate of zinc. The ore
is first roasted, and then mixed with some carbonaceous flux, and
submitted to the action of heat in close vessels. The metal is
volatilized, and passes over, and is usually caught in water. It is
then fused, and cast in moulds.
Zinc possesses many remarkable properties, some of which are the
following. It is of a brilliant white colour, with a shade of blue,
and is composed of a number of thin plates, adhering together. Its
specific gravity is more than six times that of water. It is brittle,
but, when heated to 212 degrees, may be hammered out, or made into
sheets. At 400° it becomes very brittle. Its tenacity is so feeble,
that a wire of 1/10th of an inch in diameter, will support a weight
of only 26 pounds. At 680° it melts, and above that temperature,
evaporates. It soon oxidizes, and its lustre is therefore tarnished.
At common temperatures, it soon decomposes water; and, when the
vapour of water is passed over it at a high temperature, the
decomposition is very rapid, the oxygen of the water being absorbed.
Zinc is soon oxidized when melted and exposed to the air, forming a
gray oxide.
At a red heat, zinc inflames, and the product of combustion is the
white oxide of zinc, or flowers. The oxide of zinc is reduced by
mixing it with charcoal, and exposing the mixture to a strong heat in
close vessels.
Zinc will burn in chlorine gas, and forms a chloride of zinc. If the
perchloride of mercury and zinc-filings be heated together, the same
compound will result. This chloride melts at 212°, and rises, in the
gaseous form, at a heat much below ignition. It was formerly called
the _butter of zinc_, and muriate of zinc. With iodine, zinc forms a
compound, called iodide of zinc.
With phosphorus and sulphur, zinc also combines, and with the latter,
it forms the native sulphuret, known by the name of blende. It
unites, also, with acids, and forms salts. Of these, the sulphate of
zinc, or white vitriol, is the most common. It unites with various
metals, forming alloys. Of these, that with copper, called brass, is
the most known. Zinc, with copper, forms galvanic batteries. With
tin and mercury, it constitutes amalgam for electrical machines. It
forms, besides brass, the yellow copper, or laiton; commonly called
pinchbeck.
Acetic acid readily dissolves zinc. The acetate formed is not altered
by exposure to the air, is soluble in water, and burns with a _blue_
flame. It may be used, therefore, in fire-works, to communicate that
colour to flame. It may be formed very expeditiously, by mixing about
equal parts of sulphate of zinc, and acetate of lead, both being in
solution. The sulphate of lead, which is formed, will precipitate,
and acetate of zinc remain in solution. By evaporation, it is
obtained in crystals. This salt cannot injure any composition of
fire-work, in which it enters; as it does not deliquesce, and, for
that reason, may be advantageously employed.
When zinc is used in fire-works, it should be remarkably fine.
The powder may be very readily formed, by heating it, until it is
about to fuse, and pulverizing it while hot, in a warm mortar. It
is generally considered, however, that the best method of obtaining
the powder of zinc, although a longer time is required, is by filing
it; but the filings are more or less coarse, according to the file
which is used. They may be sifted, and thus obtained of any degree of
fineness. In various blue lights, in the blue flame of the parasol
and cascades, and other descriptions of fire-works, it is used. It
gives a more brilliant light than any other substance used for this
purpose. It is frequently mixed with other substances; but, as to its
peculiar properties, they remain the same. By the combustion of zinc,
which follows in fire-works, it always produces an oxide. In this
state, it is expelled, or thrown off.
Acetate of zinc appears to possess advantages over zinc-filing,
especially as it produces the same colour, may be more readily mixed,
and with more accuracy, and does not deliquesce or absorb moisture,
a circumstance which must always be guarded against in artificial
fire-works.
_Sec. XLIII. Of Brass._
This is a mixed metal, composed of copper and zinc. This alloy,
according to the proportion of the metals, is more or less yellow,
or reddish-yellow. The yellow copper, or _laiton_ of the French, the
similor, Manheim gold, prince Rupert's metal, &c. are alloys of the
same metals.
Zinc readily unites with copper; and the usual manner of forming
brass by brass-founders, is to make a direct union between the two
metals. The process, however, generally consists in mixing together
granulated copper, calamine, or carbonated oxide of zinc, and
charcoal in powder, and melting them in a crucible. The charcoal
reduces the zinc, which then unites with the copper. The heat is kept
up for five or six hours, and towards the last of the process, is
raised. Zinc, in small proportion, renders copper pale, and in the
proportion of one-twelfth, inclines its colour to yellow. The yellow
colour increases in intensity with the zinc, until the weight of this
metal in the alloy equals that of the copper. An increase of zinc,
afterwards makes the alloy white. English brass contains one-third
of its weight of zinc. In Germany and Sweden, the proportion of zinc
varies from one-fifth to one-fourth of the copper. Twenty to forty
parts of zinc, with eighty to sixty parts of copper form the _cuivre
jaune_, laiton, or yellow copper of the French.
Dutch metal, or Dutch gold, is a fine kind of brass, and comes in
leaf, which is about five times as thick as gold leaf. This brass is
made by the cementation of copper plates with calamine, and hammered
out into leaves.
According to Thenard (_Traité de Chimie_, tome i, p. 478), the
French use 50 parts of calamine, mixed intimately with 20 parts of
charcoal, and stratified in a crucible with 30 parts of laminated, or
granulated copper. British brass consists of two parts of copper, and
1-1/8 parts of zinc, by weight.
The filings of brass are much employed in fire-works. They
communicate to stars, rains, &c. a flame between a blue and green. In
some, the filings of copper alone are used. A beautiful green fire,
for instance, is produced by 16 ounces of gunpowder, and 3-1/4 ounces
of copper-filings. Verdigris is also employed for the same purpose;
but the effect is not so striking, as in that preparation, the copper
is already oxidized. The effect of copper in fire-works, it is to be
recollected, depends, like that of other metals, on its combustion,
and consequent oxidizement. The product of the combustion of brass,
is oxide of copper, and oxide of zinc.
_Sec. XLIV. Of Bronze._
The union of copper with tin, in various proportions, forms
gun-metal, bell-metal, the mirrors of telescopes, and bronze.
The ductility of the copper is diminished by the tin; but its
hardness, and tenacity, as well as its fusibility and sonorousness
are increased.
To form a complete union of the two metals, they should be continued
in fusion for some time, and constantly stirred. The tin is apt to
rise to the surface, unless this precaution is used.
Bronze is usually composed of 100 parts of copper, and 8 to 12 parts
of tin. It is yellow, brittle, heavier than copper, and has more
tenacity.
The same metals, and in the same proportion, constitute gun-metal.
In the brass ordnance made at Woolwich, the proportion of tin varies
from 8 to 12, to the 100 parts of copper. The purest copper requires
the most. That the alloy is more sonorous than iron, is evident from
the report of brass pieces, being louder than that occasioned by iron
guns.
When the alloy is 78 of copper and 22 of tin, it is chiefly used for
clocks. There is, in the English metal, about five per cent. of zinc,
and four per cent. of lead. The proportion of tin, in bell-metal,
varies. In church bells, less tin is used than for small bells. In
the latter, zinc is sometimes added.
The _Tam-tam_, or _gong_ of the Chinese, used for cymbals, clocks,
mirrors, &c. contains, according to analysis, 80 parts of copper, and
20 parts of tin. The proportions, however, are not always the same.
The ancients made cutting instruments of an alloy of copper and tin.
A dagger, analyzed by Mr. Hielm, consisted of 83-7/8 copper, and
16-1/8 tin. Vessels of bronze were frequently covered with silver.
Some of this kind were found in the ruins of Herculaneum.
Pliny observes, that ancient mirrors were made with a mixture of
copper and tin; but that, in his time, those of silver were so
common, that they were even used by the maid servants. The quantity
of tin, to make the most perfect speculum, depends on the quality of
the copper. If the proportion of tin be too small, the composition
will be yellowish; if it be too great, the composition will be of
a grayish-blue colour. Mr. Edwards casts the speculum in sand with
its face downwards; takes it out while red-hot, and places it in
hot wood-ashes to cool, otherwise it would break in cooling. The
mixture is first granulated, by pouring it into water, and then
fused a second time for casting. Mr. Little recommends the following
proportions: 32 parts of the best bar copper, 4 parts of brass, or
pin wire, 16-1/2 of tin, and 1-1/4 of arsenic.
Whether for speculum metal, bronze, or gun-metal, the metals must be
mixed exactly, and for this purpose be kept a long time in fusion,
and constantly stirred; otherwise, the alloy will not be of a uniform
quality, as the greater part of the copper will sink to the bottom,
and the greater part of the tin rise to the surface. When we speak of
_brass guns_, as that name is generally applied to them, we are to
understand, that they are not made, like brass, of an alloy of copper
and zinc.
The ancient metallic mirrors, which were in use before the present
mirrors, or the discovery of glass, and the mode of applying to its
surface an amalgam of tin, were composed of two parts of copper and
one part of tin. Mr. Mudge asserts, that the best proportion for
mirrors is 32 parts of copper and 14.5 parts of tin. Klaproth found
a specimen of ancient mirror to consist of 32 of tin, 8 of lead,
and 62 of copper. The alloys of copper and tin may be decomposed by
dissolving them in an acid, the muriatic for instance, and immersing
a sheet of iron, which will precipitate the copper. The tin may then
be separated by immersing a plate of lead, or zinc, by either of
which metals, it will be precipitated.
Bronze, being a mixed metal, in which the copper forms the principal
ingredient, is sometimes used in fire-works, in lieu of copper or
brass; for its effects are similar. By the combustion of bronze
filings, we have an oxide of copper and an oxide of tin.
_Sec. XLV. Of Mosaic Gold._
This name, or _aurum musivum_, was given to a preparation of tin,
composed of tin and sulphur. It is considered to be a persulphuret of
tin.
Several methods are recommended for preparing this substance. The
oldest process is to sublime a mixture of 12 parts of tin, 7 parts of
sulphur, 3 parts of mercury, and 3 parts of sal ammoniac. It may be
formed by heating together in a retort, a mixture of equal parts of
sulphur and oxide of tin.
It is used principally for rubbing the cushions of electrical
machines, and for bronzing wood. In fire-works, it is sometimes
employed under the name of _gold-powder_.
It was supposed to be a combination of sulphur with the oxide of tin.
Dr. J. Davy (_Phil. Trans._ 1812, p. 199) and Berzelius, (_Nich.
Jour._ xxxv, 165), have proved, however, that it is nothing more than
metallic tin and sulphur; the proportions of which, according to the
former, are 100 of tin + 56.25 of sulphur.
Mosaic gold is of a yellow colour, resembling that of gold. It is
insoluble in water, and is not acted upon by muriatic or nitric acid.
The nitromuriatic, however, decomposes it. A solution of caustic
potassa dissolves it, forming a green solution, which is decomposed
by acids, letting fall a hydrosulphuret of tin. It deflagrates with
nitre.
When it is used in fire-works, it is pulverized, and sifted. It is
more generally employed as a pigment to impart a golden colour to
small statues of plaster-paris. When mixed with melted glass, it is
said to imitate lapis lazuli.
_Sec. XLVI. Of Iron and Steel._
Both iron and steel are used abundantly in fire-works. It would be
unnecessary to detail the preparations, in which they are employed,
which may be seen by a reference to the different kinds of fire, and
to their respective formulæ.
Cast iron is more employed in artificial fire than forged iron
or steel, at least in the preparation of some, as gerbes, white
fountains, and Chinese fire.
The filings of iron and steel may be sifted through sieves. A fine
hair sieve will answer for common purposes. Their fineness depends,
in the first instance, on the file, which is used. Steel or iron
filings are more commonly employed in the compositions for brilliant
fire.
The sparks produced by cast-iron are very brilliant; but the
reduction of the iron to powder, or to a degree of fineness
sufficient for use, is a difficult operation. It is of too hard a
nature to be cut by a file.
This operation is generally performed in the following manner:
Procure from an iron foundry, some thin pieces of cast iron, such as
generally run over the mould at the time of casting, and pound them
on a block, made of cast iron, with an iron hammer of four pounds
weight, putting, under the block, a cloth to catch the pieces of
iron, which fly off. They are beaten with the hammer in this manner,
until the whole is reduced to grains, which are more or less small.
It is then thrown into a sieve, which should be fine, and the dust
separated. This is used, in the place of steel dust, in small cases
of brilliant fire. The remainder is then put into a sieve, a little
coarser, and again sifted. This portion is preserved separately. The
same operation is repeated, but with sieves of different sizes, till
the iron passes through about the bigness of small bird shot.
The pulverization may be effected in an iron mortar, with a steel
pestle, having the mortar covered in the usual manner, to prevent the
escape of the finer particles of the iron.
According to a writer in the _Dictionnaire de l'Industrie_, vol.
iii, p. 34, the Chinese prepare their iron-sand for fire-works by
igniting iron, and plunging it in cold water. They then pulverize the
scales thus formed, and pass the powder obtained, through different
sized sieves, which is then called No. 1, 2, 3, 4, &c. as it is
very fine or coarse. This cannot be a good method, and we doubt
whether it is at present employed; because it is obvious, that the
scales, in this case, consist of the metal in the state of protoxide.
D'Incarville, a missionary at Pekin, obtained the process for making
Chinese fire; and observes, that the pulverized cast iron they employ
is called _iron-sand_, of which they have six numbers or varieties.
As the goodness of iron or steel dust, in fire-works, depends greatly
on its being dry, and not oxidized or rusted; its preservation must
be accordingly attended to. The usual preservative is to put it in
a box, lined with oiled paper, and covered with the same, or in tin
cannisters, with their mouths well closed.
When it is to be used, it is taken according to its size, and in
proportion to the cases, for which the charge is intended. Large
gerbes, of 6 or 8 lbs. require only the coarse sort.
As the brilliancy of the sparks, produced by the iron and steel dust,
is a desideratum in the formation of some fire-works, and as this
brilliancy depends upon the nature and quality of the metal, it may
not be improper to offer some remarks on these subjects.
That iron, when finely divided is capable of producing sparks of
fire, is a well known fact; and we see it daily in the operations
of the smith, when ignited iron is hammered on the anvil. The
scintillation produced by the steel, when struck with a flint, is of
the same character. In the latter case, the metal is actually fused,
and, when caught on a paper, and examined with a microscope, will
appear globular, and partly oxidized. Hence it is, that gunpowder is
inflamed by this spark, which is nothing more than highly ignited,
and inflamed iron, possessing a temperature more than sufficient to
inflame gunpowder.
The effect, therefore, that results from the inflammation of
fire-works, in which iron or steel forms a constituent part, is
nothing more than a vivid combustion of the metal; and during that
process it becomes oxidized, as it does not form an acid with oxygen,
like arsenic, antimony, and some other metals.
The combustion of iron or steel may be shown by a very brilliant
experiment, that of burning it in oxygen gas. A steel wire,
harpsichord wire for instance, formed into a spiral, with a small
piece of wood dipped in sulphur, stuck on its end and then set on
fire, upon being immediately introduced into a bottle, containing
pure oxygen gas, will burn with great brilliancy, emitting a number
of sparks or scintillations, which fall like rain. In making the
experiment, some sand should be put into the bottle to prevent the
sparks from breaking it. This experiment illustrates the rapid
combustion of iron, or steel. For the oxygen gas supports the
combustion; and while the oxygen is actually taken up by the metal,
which becomes oxidized, and therefore increased in weight, in the
same manner as it does when inflamed in fire-works, the caloric, the
other constituent of oxygen gas, is given out in a free state, and,
with the light at the same time evolved, produces the phenomena of
combustion.
Many other experiments might be mentioned, in which the same effects
take place, and from which the same conclusions may be drawn. But
with respect to the _effect_, whether it be dull, brilliant, or
very brilliant, depends more on the quality of the metal, than
perhaps, on its subsequent mixture with the other materials. Crude
iron, usually called cast iron, seems to possess this property in
an eminent degree; but in the experiment with oxygen gas, steel is
always preferable, as the combustion is more rapid, and the effect
more striking. The difference, which we will not attempt to explain,
may depend on the _state_, as well as the _proportion_ of carbon,
which enters into crude iron, as well as steel. In one case, the
combustion ensues in contact with nitre, and in atmospheric air; in
the other, in contact only with oxygen gas. Be this as it may, this
inference is conclusive, that, in all cases of the combustion of iron
in fire-works, the metal itself unites with oxygen, and the result of
the combustion is an oxide of iron; and with respect to the carbon,
in both instances, it is converted alike into carbonic acid. So that
whether the iron receives its oxygen from the nitre, or from the air,
or from both, is immaterial, as the products are the same.
When iron is exposed to the atmosphere, it tarnishes, and is
gradually changed into a brown or yellow powder, called rust. This
change is owing to its combination with oxygen; and its affinity
for oxygen is such, that, when the vapour of water is made to pass
through an ignited gun-barrel, it is decomposed, the metal becoming
oxidized, and the hydrogen, the other constituent of the water, being
liberated in the form of gas.
Gun barrels are browned by a process of oxidizement. There are
several processes recommended. One of which is, to rub the barrel
over with diluted nitric or muriatic acid, and then, to lay it by
for a week or two, until a complete coat of rust is formed. A brush,
made of iron wire, is then applied; afterwards, oil and wax, and
the barrel is finished by rubbing it with a cloth. The gunsmiths in
Philadelphia use a mixed solution of sulphate of copper, tincture
of the muriate of iron, and sweet spirit of nitre. This they apply
by means of a cloth. The object is to form a rust, and to render
it permanent on the barrel by hard friction along with wax. When
sulphate of copper is employed, metallic copper is precipitated
on the barrel. A coat of rust, put on in this manner, prevents
effectually the oxidizement of the iron; and in point of utility, and
the saving of labour in polishing and keeping muskets in order, the
browning of barrels is certainly advantageous in the land service.
At sea, in particular, where iron is more readily oxidized, this
plan ought always to be adopted. With regard to the use of dragon's
blood, it is entirely too temporary in its effect to be depended on.
I was informed by an intelligent gunsmith, who followed the practice
of browning barrels in Europe, that he has known the _browning_ to
remain very perfect for years, and that the best mode of insuring its
durability is to use the _steel brush_, which _carries in_, as he
expressed it, the rust.
The oxides, which are formed by the union of oxygen with iron, are
two; namely, the black and the red; the first being the protoxide,
and the last the peroxide. The black oxide, which is formed by
the combustion of iron, and by other processes, contains 56 iron
+ 16 oxygen. The common rust of iron is the peroxide of this
metal, combined with carbonic acid. It may be formed by exposing
the protosulphate of iron, or green vitriol, in solution, to the
atmosphere, and then adding an alkali. This oxide contains more
oxygen than the preceding; it consisting of 56 iron + 24 oxygen.
The tempering of cutting instruments, an operation which requires
great delicacy and exactness, after that of hardening, is intended
to obtain a fine and durable edge; and as this subject may be
interesting in a military point of view, we deem the following
remarks of use.
The hardening of steel instruments is performed by heating them to
a cherry-red, and then immersing them in cold water. The tempering
is another process, calculated, as we observed, to obtain a fine
and durable edge. This is performed by heating oil to a certain
temperature, and plunging the instrument into it, where it remains
until the colour appears, indicative of the particular kind of
temper which is intended to be given. The experiments of Stoddart,
(_Nicholson's Quarto Journal_, iv, 129,) are conclusive on this
subject; for his experiments prove, that, between 430° and 450° the
instrument assumes a pale yellowish tinge: at 460° the colour is a
straw-yellow, and the instrument has the usual temper of pen-knives,
razors, and other fine edge tools. The colour gradually deepens as
the temperature rises, and at 500° becomes a bright brownish metallic
yellow. As the heat increases, the surface is successively yellow,
brown, red, and purple, to 580°, when it becomes of a uniform deep
blue, like that of watch springs. Before the instrument becomes
red-hot, the blue changes to a water colour, which is the last
distinguishable colour. These different shades are owing to the
oxidizement of the surface of the metal; and the art of ornamenting
_sword-blades_, knives, &c. long practised in Sheffield, depends on
this principle. The general process is, that an oily composition
is used, with which flowers and various ornaments are painted. On
the application of the heat required for tempering it, that part
which was covered with the composition, is not altered, whereas, the
uncovered parts of the blade are changed. These ornaments, when the
paint is removed, have the natural colour of polished steel. When
steel is heated in hydrogen gas, no appearance of the kind takes
place, a fact which shows, that it is owing to the oxidizement of the
metal.
Iron is soluble in the acids. By the assistance of water, it is
acted upon by sulphuric acid; the metal being oxidized, and the
oxide dissolved, while hydrogen gas is evolved. The salt, formed in
this case, is the sulphate of iron, green vitriol, or copperas. With
muriatic, nitric, acetic and other acids, it forms various salts;
and with gallic acid, when the iron is peroxidized, it forms the
pergallate of iron, or common writing ink, and also the bases of
black dye.
Iron unites with carbon, sulphur and phosphorus. Of the sulphurets,
there are two kinds, the protosulphuret and persulphuret. The former
is the magnetic pyrites, and the latter, cubic pyrites, from both of
which, green vitriol is obtained by decomposition. Pyrites, we may
observe, was the original fire-stone, or the _feuer-stein_ of the
Germans, which was used in the place of flint. See _Beckman's History
of Invention_. Iron also unites with some of the metals, forming
alloys. The white iron of the French, (_Fer blanc_,) or tin plate of
the English, is found to be any alloy of tin with iron, as well as a
covering of tin on iron.
Sheet tin, or tinplate which is necessary in the construction of the
apparatus for some fire-works, for canister shot, &c. is made by
immersing sheets of iron, previously freed from rust, into melted
tin. The number of dippings it undergoes, determines, in some
measure, its quality and character.
The union of carbon and iron, forming very important modifications
of this metal, is not only interesting in the military art, as
concerns the metal for cannon, small arms, and fire-works, but also
in relation to the many and highly useful compounds which result.
All the varieties of iron, which are distinguished by artists, under
particular names, we may consider under the following heads: namely;
cast iron, wrought or soft iron, and steel.
Cast or pig iron is the name of this metal, when first obtained from
the ore. The ores of iron are various, and contain a greater or less
quantity of iron, which is either combined with oxygen, or found with
clay, giving rise to two important classes of iron ore, the calciform
and the argillaceous. The reduction of the ore merely requires the
presence of charcoal, and occasionally some addition, as limestone,
when the clay iron ores are to be reduced. On the application of
heat in furnaces, constructed for the purpose, the charcoal unites
with the oxygen of the oxide, reducing it to the metallic state, and
escapes in the form of carbonic acid; and the lime, if the ore be
argillaceous, unites with the clay, forming a kind of glass, which
floats on the melted metal. When the iron is suffered to run into
moulds, prepared for its reception, it usually takes the name of pig
iron.
Manufacturers distinguish cast iron by its colour and other
qualities. The _white cast iron_ is hard and brittle, and can neither
be filed, bored, nor bent. Gray mottled iron, so called from its
colour, is of a granulated texture, softer, and may be cut, bored and
turned on the lathe. Cannon are made of this iron. _Black cast iron_
is the most unequal in its texture, but the most fusible.
Cast iron melts at 130° of Wedgwood. Its specific gravity varies
from 7.2 to 7.6. It is converted into malleable, usually called soft
iron, by a process called refinement. Several modes have been adopted
for this purpose. It was formerly done by keeping it in fusion in a
bed of charcoal and ashes, and afterwards forging it. The hammering
makes the particles of iron approach each other, and expels some
impurities.
Among the various improvements for expeditiously and effectually
converting crude into malleable iron, the process of Mr. Cort seems
to possess advantages. The cast iron is melted in a reverberatory
furnace, and the flame of the combustible is made to act upon the
melted matter. It is stirred during this operation, by which means,
every part is exposed to the air. A lambent blue flame begins to
appear in about an hour, and the mass swells. The heat is continued
about an hour longer; and, by this time, the iron acquires more
consistency, and finally congeals. While still hot, it is next
hammered by powerful tilt-hammers. This is called the _puddling_
process.
Iron, obtained in this way, is not however pure; for it contains
either some of the other metals, or oxygen, carbon, silicon, or
phosphorus.
When small pieces of iron are stratified in a crucible with charcoal
powder, and exposed to a strong heat for eight or ten hours, they are
converted into steel. Steel is brittle, resists the file, cuts glass,
and affords sparks with flint. It loses its hardness by ignition and
cooling. It is malleable at a red heat. It melts at 130 degrees of
Wedgwood. By being repeatedly ignited in an open vessel, it becomes,
by hammering, wrought iron.
Natural steel is that which is formed, by converting the ore first
into cast-iron, and exposing it to the action of a strong heat, while
the melted scoriæ float on its surface. This steel is inferior to
the others. Steel of cementation is formed, on a large scale, by
stratifying bars of iron with charcoal, in large earthen troughs or
crucibles, the mouths of which are closed with clay. These troughs
are put in furnaces, and, in eight or ten days, the process is
finished. This is also called blistered steel, on account of the
appearance of its surface. The tilted steel is that which is beaten
out into small bars by the hammer. When broken, and the pieces again
united by welding in a furnace, and made into bars, it is then called
German or shear steel.
Cast steel is considered the most valuable of all the varieties; and
is used for the manufacture of razors, surgeons' instruments, &c. It
is, besides, more fusible than common steel, and for that reason,
cannot be welded with iron. It is made by melting the blistered
steel, in a close crucible, along with pounded glass, and charcoal
powder. It may also be formed by melting together 30 parts of iron,
1 part of charcoal, and 1 part of glass. Equal parts of chalk and
clay, put with iron in a crucible, will also produce it.
The Celtiberians in Spain had a singular mode of preparing steel.
Diodorus and Plutarch both say, that the iron was buried in the
earth, and left in that situation, till the greater part of it was
converted into rust. What remained, without being oxidized, was
afterwards forged and made into weapons, and particularly swords,
with which they could cut asunder bones, shields, and helmets.
This process is used in Japan, however improbable it may seem;
and Swedenbourg, among the different methods of making steel, has
introduced it. Bishop Watson, (_Chemical Essays_ 8vo. i, p. 220,)
speaks of the same process. The fact has been verified at Gottingen;
for an anvil, which had been buried in the ground for many years,
was found to be extremely soft; and a part of it, which appeared in
steel-like grains, possessed the properties of steel.
The sabres made in Japan, according to Thunberg, are incomparable.
Without hurting the edge, they can be made to cut through a nail at
one blow.
The art of hardening steel by immersion in cold water is very old.
Homer (_Odyssia_ ix, 301,) says, that, when Ulysses bored out the
eye of Polyphemus with a burning stake, it hissed in the same manner
as water, when the smith immerses in it a piece of red-hot iron, in
order to harden it. Sophocles, Salmasius, Pliny, Justin and others
mention the use of water in hardening iron; but the most delicate
articles of that metal were not quenched in water, but in oil. As to
the opinion of the peculiar virtue of any particular water, for the
purpose of hardening iron, which many have believed, it is altogether
fallacious, although Vasari asserts, that the archduke Cosmo, in
1555, discovered a water, that would harden instruments, to cut, like
the ancient tools, the hardest porphyry. The art of working porphyry,
however, was known in every age. Beckman assures us, when treating
of the processes of making steel, that the invention and art of
converting bar iron into steel, by dipping it into other fused iron,
and suffering it to remain there several hours, although ascribed to
Reaumur, (_Art de Convertir le Fer en Acier_, p. 145), are mentioned
by Agricola, Imperati, and others, as a thing well known and
practised in their time.
Pliny, Diamachus, and other ancient writers mention various countries
and places, which, in their time, produced excellent steel. The
_ferrum Indicum_ and _Sericum_ were the dearest kinds. The former is
the same as the _ferrum candidum_, a hundred talents of which were
given, as a present, to Alexander in India.
Beckman thinks, that the ancient _ferrum candidum_ is the same kind
of steel still common in India, and known under the name of _wootz_;
some pieces of which were sent from Bombay in 1795 to the Royal
Society. Its silver coloured appearance, when polished, he thinks,
may have given rise to the epithet of _candidum_.
Mr. Faraday of the Royal Institution has lately examined wootz, and
imitated it very accurately. The experiments may be seen in _Ure's
Chemical Dictionary_, article _Iron_. It appears that the presence of
silex and alumina distinguishes this kind of steel from the English.
Four hundred and sixty grains of wootz gave 0.3 of a grain of silex,
and 0.6 of a grain of alumina. It is highly probable, that the much
admired sabres of Damascus, are made from this steel.
A small portion of silver, melted with steel, improves the latter
very considerably. One part of silver and five hundred parts of
steel were melted together, and every part of the alloy formed, when
tested, indicated silver. The alloy forged remarkably well, although
very hard, and was pronounced to be superior to the very best steel.
This excellence is undoubtedly owing to its combination with the
silver, however small. The alloy has been repeatedly made, and with
the same success. Various cutting tools have been made from it of the
best quality. The silver is found to give a mechanical toughness to
the steel.
Platinum and steel, equal parts by weight, form a beautiful alloy,
which takes a fine polish, and does not tarnish. This alloy is said
to make the best speculum. Steel, for edge tools, is improved by this
metal. The proportions, which appear to be most proper, are from one
to three per cent. An alloy of 10 platinum with 80 of steel, after
exposure for many months, had not a speck on its surface. Would not
this alloy, as it is not oxidized, be very useful for making points
for lightning rods, in lieu of iron, gold, silver, or platinum alone?
The experiment is worth a trial; for nothing adds more to the safety
of a magazine, or building, against the effect of lightning, than a
conductor.
Iron and carbon, it appears, are capable of uniting in different
proportions; hence the variety of crude iron, and the different kinds
of steel. When the carbon exceeds the iron, as in plumbago, or black
lead, it forms a carburet. When the iron exceeds, such compounds are
properly speaking sub-carburets; under which name, we may rank all
the varieties of cast iron and steel.
The hardness of iron, according to the experiments of Mushet,
(_Phil. Mag._ xiii, p. 138), increases with the proportion of
charcoal, with which it combines, until the carbon amounts to
about 1/60th of the whole mass. This is the maximum, the metal
acquiring the colour of silver. More carbon diminishes the hardness,
according to its quantity. The difference in iron, whether it be the
_cold-short_, or _hot-short_ iron, a matter of some consequence to
the workers in this metal, was found to be owing to phosphoric acid
in the cold-short, which exists with the iron. But the substance,
called _siderum_ by Bergman, is a phosphuret, and not a phosphate of
iron.
We have gone into this subject more fully, on account of its
importance, and intimate connection with the casting of guns, and the
different qualities of iron. In fire-works, it will appear obvious,
that the various properties exhibited by iron are owing to the iron
and carbon, to the changes which they undergo, to the combustion
which necessarily ensues, and to the production of oxide of iron,
and carbonic acid gas; effects that invariably take place, whether
cast iron or steel be used, provided it is exposed to the action of
agents, under the same circumstances and conditions.
_Sec. XLVII. Of Glass._
Glass, in the form of powder or dust, is used in fire-works. The
pulverization of glass is easily performed. It may be done in an iron
mortar, and passed though fine wire or brass sieves. It is used in
the composition for wheels, in water balloons, cones, fire-pumps,
slow white fire, &c.
Glass is nothing more than fused silica, made by exposing a mixture
of silica and other substances to the action of a violent heat.
The quality of the glass depends on the proportion of silica, and the
fluxes which are used in promoting its fusion; for the various kinds
of glass, as white glass, green glass, bottle glass, &c. are all, in
one respect, the same, though they differ in these particulars.
The glass of Saint-Gobin in France is made by fusing white sand,
lime, soda, and broken inferior glass. The white goblet-glass is made
of sand, potash, lime, and old glass; the quantity of potash is about
fifty per cent. If green, or yellow, the colour is destroyed by the
addition of black oxide of manganese; and hence that oxide is named
_glass makers' soap_.
The common plate glass, for electrical machines, &c. is formed of
sand, crude soda, old glass, and oxide of manganese. The bottle
glass, made with the soda of marine plants, consists of sand, soda,
common ashes, and old glass. Another bottle glass is made by melting
common sand, black or yellow, with soda, wood-ashes, clay, and
broken glass. It appears from the use of the substances which enter
into, and compose, glass, that its quality is owing to the materials
employed. The crystal or flint glass is a finer kind. The substances,
with the proportions in which they are used, are the following:
_Parts._
White sand, 100
Red lead, 80 to 85
Calcined potash (pearl-ash,) 35 to 40
Refined nitre, 2 to 3
Black manganese, 0.06
To this composition, there are sometimes added:
_Parts._
White arsenic, 0.05 to 0.1
Crude antimony, 0.05 to 0.1
The specific gravity of this glass is 3.2. Goblets, lustres, &c. are
made of it.
Flint glass, according to the English formula, is made of
Purified Lynn sand 100 parts.
Litharge or red lead 60
Purified pearlash 30
To this is added black manganese, to correct the colour, and
sometimes nitre and arsenic.
Plate glass is formed of
Pure sand, 43.0 parts.
Dry carbonate of soda, 26.5
Pure quicklime, 4.0
Nitre, 1.5
Broken plate glass, 25.0
------
100.
Crown, or fine window glass, is composed of
Fine sand, 200 lbs.
Best kelp, ground, 330 lbs.
To this is added, if the vitrification is not complete, some muriate
of soda. Good glass, according to Pajot des Charmes, may be made
by fusing equal parts of carbonate of lime, sand, and sulphate of
soda. The glass is clear, solid, and of a pale yellow. Professor
Scheweigger found, that the following proportions were the best:
Sand, 100
Dry sulphate of soda, 50
Dry quicklime in powder, 17 to 20
Charcoal, 4
Broad glass is made of a mixture of soap-boilers' waste, kelp, and
sand. Two of waste, one of kelp, and one of sand are the proportions
generally employed. Common bottle glass is usually made of waste and
river sand, to which lime, and clay, and common salt are occasionally
added.
The coloured glasses are produced by various metallic oxides. The
colour and beauty of precious stones are thus imitated. These colours
are communicated by sundry metallic preparations, as the following:
The purple powder of Cassius, with oxide of manganese, will give a
red or purple according to the proportions used; zaffre, an oxide of
cobalt, a blue; a mixture of oxide of cobalt, muriate of silver, or
glass of antimony, a green; and oxide of manganese, a violet, &c.
The basis of all artificial precious stones, is composed of what is
called glass-paste, a compound of silica, potash, borax, red lead,
and sometimes arsenic. These substances are melted together. The
glass, which forms the body of the artificial gem, is pulverized, and
the colouring substances are blended with it by sifting; and then the
whole must be carefully fused, being left on the fire for from 24 to
30 hours, and cooled very slowly. The following proportions are used
for this purpose:
_Pastes._ 1. 2. 3. 4.
Rock crystal, 4056 gr. ---- 3456 360
Minium, 6300 ---- 5328 ----
Potash, 2154 1260 1944 1260
Borax, 276 360 216 360
Arsenic, 12 12 6 ----
Ceruse of clichy, -- 8508 ---- 8508
Sand, -- 3600 ---- ----
_Topaz._ No. 1, No. 2.
Very white paste, 1008 3456
Glass of antimony, 43 ----
Cassius purple, 1 ----
Peroxide of iron, (saffron of Mars,) -- 36.
_Ruby._ Paste 2880, oxide of manganese 72.
_Emerald._ Paste 4608, green oxide of copper 42, oxide of
chrome 2.
_Sapphire._ Paste 4608, oxide of cobalt 68, fused for 30
hours.
_Amethyst._ Paste 4608, oxide of manganese 36, oxide of
cobalt 24, purple of Cassius 1.
_Beryl._ Paste 3456, glass of antimony 24, oxide of cobalt
1-1/2.
_Styrian garnet_, or ancient carbuncle. Paste 512, glass of
antimony 256, Cassius purple 2, oxide of manganese 2.
The following recipes are given by M. Lancon:
_Paste._ Litharge 100, white sand 75, potash 10.
_Emerald._ Paste 9216, acetate of copper 72, peroxide of
iron 1.5.
_Amethyst._ Paste 9216, oxide of manganese from 15 to 24,
oxide of cobalt 1.
The ancient coloured glass has been much admired. The art was carried
to a very great extent. Even in Pliny's time, the highest price was
set upon glass entirely free from colour. He, as well as others,
mentions that hyacinths and sapphires were imitated very exactly.
The emperor Adrian received as a present from an Egyptian priest,
several glass cups richly ornamented with various coloured glass.
Seneca speaks of the knowledge of Democritus in this art. Porta,
Neri, and others, in modern times, have treated the subject in a
more enlarged manner. Coloured glass was used for ornament; but
Pollio relates, that Gallenius punished an impostor for selling to
his wife a piece of glass for a jewel. In the _Museum Victorium_ at
Rome, are several ancient artificial gems, such as the chrysolite and
emerald. What materials the ancients used for colouring glass is not
known. Gmelin, however, observes, that it is probable they made use
of iron, by which, he adds, not only all the shades of red, violet
and yellow, but even a blue colour might be communicated. Cassius
discovered the powder which bears his name. He was a physician, and
resided at Lubec.[22] This powder was employed by the German artists.
While noticing this subject, it may be proper to state, that Libavius
(_Alchemy_, 1606,) gives a process for making ruby glass. Neri, (_ars
vitraria_ by Kunkel,) was acquainted with the gold-purple and its
use. Glauber (_Furnus Philosophicus_, 1648) mentions the use, and
gives the preparation of the powder. Kunkel made artificial rubies in
great abundance, and a cup of ruby glass for the elector of Cologne.
In 1679, he was inspector of the glass houses at Potsdam; and, in
perfecting the art, he expended 1600 ducats, which the elector of
Brandenburgh gave him for the purpose.
M. Brongniart has lately made many experiments on the subject of
staining glass. The colours, however, are the same as we noticed. A
green glass may be made by putting on one side of the glass a blue,
and on the other a yellow. A black glass may be made by a mixture of
blue with the oxides of manganese and iron. Painting on glass is an
ancient art. When pieces of old painted glass are examined, they have
always on one side a transparent red _varnish_ burnt into them. The
moderns, however, excel in this art.
Glass is not acted upon by the acids, except the fluoric or
hydrofluoric. Hence the acid of Derbyshire spar, which is a fluate of
lime, is used for etching on glass, in the same manner as nitric acid
is, on copper. Fluoric acid, a compound of fluorine and hydrogen, is
decomposed during this action, and is changed, by the union of its
fluorine with silicon, into the silicated fluoric acid.
When a quantity of alkali is used just sufficient to fuse silica,
glass is the result; but when the quantity is greater, as three or
four to one, the fused mass is soluble in water, and then forms
the silicated alkali, or liquor of flints. From this the silica is
obtained in a pure state, by the addition of an acid.
Glass, when melted and dropped into water, assumes an oval form, with
a slender projection, called a tail. This is called Prince Rupert's
drop. If a small part of this tail be broken off, the whole bursts
into powder, with a kind of explosion. The Bologna, or philosophical
phial, is a small cylindrical vessel of glass, rounded at the bottom,
but open at the upper end. It is made thick at the bottom, so as
not to be easily broken; but if a pebble be dropped into it, it
immediately cracks, and the whole falls into pieces. In both these,
(the drop and the bottle,) the glass is unannealed. When the external
part of glass is suddenly cooled, the inner part is kept, as it were,
contracted. Now annealing, the process of tempering glass in an oven,
renders the glass uniformly alike, and capable of sustaining the
variations of temperature, without breaking. By a crack or fissure,
the internal parts which remained in a state of tension, endeavour to
recover the full state of expansion, and consequently the glass is
rent asunder.
_Sec. XLVIII. Glue and Isinglass._
Both glue and isinglass are animal products. They are used in
fire-works, but always in the state of solution, as vehicles to
mix up compositions in order to make them unite, and to preserve
them from falling to powder. The quantity, however, is never large,
or either would destroy the effect. The proportions are generally
prescribed. A solution of glue is employed in the old process for
refining saltpetre. See _Nitre_. In making priming paste, isinglass
dissolved in brandy is sometimes used.
Glue and isinglass owe their adhesive quality to the presence of
gelatin; the most remarkable property of which is, that it unites
with, and precipitates the tanning principle from its solution in
water. For this reason, the use of oak bark and other astringent
substances, in the tanning of leather, is obvious, the gelatin of the
hide or skin, uniting with the tannin and forming tanned leather.
Gelatin exists in bones, muscles, tendons, ligaments, membranes and
skins. Skins, especially those of old animals, furnish the best and
strongest glue.
For the preparation of glue, the parings and offals of hides, pelts,
and the hoofs and ears of horses, oxen, calves, sheep, &c. are first
digested in lime-water to clean them; then steeped in fresh water,
which is suffered to run off; and being previously inclosed in a
strong linen bag, are boiled in a copper cauldron with pure water.
The impurities are removed as they rise. To the solution, alum, or
finely powdered lime, is added. It is then strained through baskets
and allowed to settle; after which, the clear fluid is again boiled.
When it becomes thick, or of a proper consistence, it is poured into
moulds or frames, when it concretes into jelly. It is cut into pieces
by a spade, and then into thin slices by means of wire, and finally
dried on coarse net-work.
The goodness of glue is known by its brittleness, and equal degree of
transparency, without black spots. It swells up in cold water, and
becomes gelatinous, but does not dissolve. It is a mark of want of
_strength_, when glue dissolves in cold water.
Size is also a gelatinous substance, and is colourless and
transparent. Eel skins, vellum, parchment, &c. are used in its
preparation. They are treated in the same manner as hides. Isinglass,
or fish glue, is a finer kind of gelatin, obtained from the air
bladder and sounds of different kinds of fish of the _accipenser_
genus; as the _sturio stellatus_, _huso ruthenses_, _&c._ The
bladder, when taken from the fish, is washed and stripped of its
exterior membrane, and then cut lengthwise and formed into rolls, or
cut into strips. Isinglass dissolves in water with more difficulty
than glue. A coarser kind of fish glue is made from sea wolves,
porpoises, sharks, cuttle fish, the sturgeon, &c. The head, tail,
fins, &c. are boiled in water, and the solution evaporated. Isinglass
is used for a variety of purposes, as the making of court plaster and
size, the clarification of liquors, &c.
Isinglass is almost wholly gelatin. One hundred grains give
ninety-eight of soluble matter.
Gelatin constitutes the greater part of the solid parts of animals,
such as bone, ligament, muscle, membrane, skin, &c. and is always
extracted by boiling them in water. We need hardly remark, that
it constitutes the chief part of soup, which owes its nutritive
qualities principally to its presence. The portable soup is nothing
more than concrete gelatin, with other substances, as spices, salt,
&c.; for it contains, in a small compass, the nutritive parts of
beef, veal, and other animal substances, from which it may have been
prepared.
Besides the use of water for extracting, or otherwise separating, the
gelatin from bone, we may separate the phosphate of lime entirely
from the latter, (as these two substances constitute the greater part
of bone), by the action of dilute muriatic acid, which will dissolve
the phosphate of lime, and leave the gelatin.
_Sect. XLIX. Of Wood._
Of the kinds of wood, used for the preparation of coal, for the
purpose of gunpowder, those should be preferred, which are light, and
will give a tender charcoal. This subject was fully considered under
that head.
But our intention, in noticing wood at this time, is, that it is
employed in the composition of some fire-works in the form of
saw-dusts, or raspings. Its use in fire-works may be considered,
1st, as producing a particular coloured flame: 2dly, as varying the
character of the flame, and likewise the degree of the combustion;
and 3dly, as communicating an agreeable odour along with other
substances; as in odoriferous fire-works. To this, we may add its use
in smoke-balls along with nitre and sulphur.
The raspings of wood are sometimes required to be extremely fine.
This can only be done by employing sieves of different degrees of
fineness. They should be preserved from the action of moisture.
In the composition of the new priming powder, of which chlorate of
potassa is the basis, very fine raspings of a particular kind of
wood are employed. So is also lycopodium for the same purpose.
By the distillation of wood, as in the process of carbonization
in iron cylinders, we obtain some volatile products, the chief of
which is the pyroligneous, now called the pyroacetic acid, while the
ligneous fibre is converted into coal; but, in the combustion of
wood, all the volatile products are expelled, some being consumed in
the flame, and others, with some carbon, condensed in the form of
soot, while the residue is an ash which furnishes common potash.
Ovid in his Metamorphoses, fable xvi, says--"Adomitis Athamanis aquis
accendere lignum narratur; minimos cum luna recessit in orbes."
This idea we know is groundless; for it is impossible, that wood,
sprinkled with water, whether the waters of Athamanis, or any other,
should be kindled when the moon is in the decrease, or at any time of
the moon's age.
To prevent the action of fire on wood, marine salt, vitriol, and
alum have all been used. Various ways of employing them have been
adopted; but they do not absolutely prevent wood taking fire in an
active heat. For the same purpose, (_Coll. Academ._ tome xi, p. 487,)
a mixture of green vitriol, and quicklime is recommended, by which
we form sulphate of lime and oxide of iron. The _Journal de Paris_
of 1781 contains various processes. At Vienna, saline substances are
employed.
The combustion of wood is the same, in all cases, in which oxygen
is concerned; but the products in some particulars may vary. Hence
saw-dust, when mixed with nitrate of potassa, and inflamed, will
burn, and produce little or no smoke, because the combustion is rapid
and perfect; but when employed with sulphur and nitre, it produces
much smoke. Here the oxygen is furnished by the nitre, and carbonic
acid gas is formed. The same thing takes place, when a mixture of
saw-dust and nitre is used in artificial fire; and, according as
the decomposition is more or less rapid, the combustion will be so
likewise. The particular applications of saw-dust will be noticed
hereafter.
With respect to _lycopodium_ or puff ball and various species of
agaric, or the medullary excrescences of trees, which are used in
some preparations of artificial fire, we may observe, that the first
is confined principally to theatrical fire-works, and the second
to the preparation of spunk, or tinder, called also pyrotechnical
sponge. See _Pyrotechnical Sponge_.
As to the substance usually called _lightning wood_, found in the
hollow of the stumps of trees, and sometimes on the surface, which,
from having lost its compactness and other characters of ligneous
fibre, is called _rotten_ wood, it is in fact the solid part of the
wood in a state of decomposition, in consequence of which, it becomes
a _solar phosphorus_. It appears to owe its phosphorescent property,
i. e. its power of shining in the dark, to the previous absorption
of light, and not, as some have suggested, to the presence of
phosphorus, or the emission of any gaseous compound, which contains
it. The process of animal putrefaction will produce such appearances,
but, in this case, the cause is different.
Turf or peat, a substance found, and employed as fuel, in some
countries, and found in boggy situations, is partially decomposed
vegetable matter, consisting of a congeries of fibres or roots. But
black mould is the result of a decomposition of vegetable substances,
in which the ligneous fibre is carbonized, and mixed with earth. The
formation of mould, however, is owing more to the decay of leaves &c.
(See _Coal_.)
Dr. Shaw (_Travels to the Holy Land_) observes, that when they were
either to boil or bake, camel's dung was their common fuel; which,
after being exposed a day or two in the sun, catches fire like
touch-wood; and burns as light as charcoal.
_Sec. L. Of Linseed Oil._
Linseed, or flaxseed, oil is obtained by expression from flaxseed.
It is a thick mucilaginous oil, when first extracted, called _raw_
oil, and in this state, is seldom used. The preparation, it undergoes
before it is used as drying oil for mixing with paints, is nothing
more than boiling it with litharge, or some oxide of lead, which
separates the mucilage, and unites with the oil. By this treatment,
it acquires the property of drying with facility, when exposed to the
atmosphere.
Linseed oil unites with great ease with oils, tallow, fat, wax, &c.
Some of these compositions are used in fire-works. A preparation
of pitch, mutton suet, and linseed oil is used, for instance,
in preventing the access of moisture to fuses; and in military
fire-works, it is employed in combination with pitch, rosin, mutton
suet and turpentine for incendiary works. Wax, and tallow, we may
here add, are also used in the preparations of similar works.
_Sec. LI. Of Gum arabic, and Gum Tragacanth._
Gum arabic, which exudes from a tree that grows in Egypt and Arabia
(_Mimosa nilotica_) when pure is transparent, and nearly colourless.
There are several varieties of this gum; the _gum senegal_, for
instance, which is of a reddish colour, and occurs in larger pieces.
Other mucilaginous substances, the peach tree gum, the cherry tree
gum, &c. which exist only in small quantities, are analogous to the
gum of the Mimosa.
Gum arabic is brittle, and for that reason may be easily reduced
to powder. It is readily dissolved in water, with which it forms
mucilage. In this state, it is employed in fire-works, chiefly as a
vehicle for the mixing of pastes, matches, &c.
Gum is a vegetable oxide, composed of carbon, hydrogen, and oxygen.
It does not crystallize. It is precipitated by some metallic salts,
as acetate of lead. It is insoluble in alcohol, which distinguishes
it from resins. Nitric acid decomposes it, and changes it into the
saclactic or mucous acid. With sugar, the same acid produces oxalic
acid.
Gum tragacanth, or gum dragon, is the produce of a thorny shrub,
which grows in Candia, and other islands of the Levant, called
_astragalus tragacantha_. The gum obtained from this shrub has many
properties in common with gum arabic, and is, therefore, used as a
paste. It dissolves readily in boiling water; but is insoluble in
alcohol, or ether.
It consists, almost entirely, of a peculiar vegetable principle,
which is called _cerasin_ by Dr. John. Cerasin has the adhesive
qualities of gum arabic, but in a greater degree. It is said to
constitute a part of the gummy matter, that exudes from the _prunus
cerasus_, _prunus avies_, _prunus domestica_, &c.
_Sec. LII. Of Cotton._
The soft down, which envelopes the seeds of different species of
_gossypium_, or cotton plant, is the cotton of commerce. These plants
are natives of warm climates. Cotton when bleached is perfectly
white. It is extremely combustible, and burns with a clear lively
flame. The ashes left behind contain potash.
Cotton is the substance, usually employed in making match rope, for
the communication of fire. It has also other uses in pyrotechny.
Cotton match is much used in fire-works for exhibition, not only for
single cases, but also for a series of cases of artificial fire,
either for fixed or moveable pieces; and serves to communicate fire,
either singly, or from one case to another, or to the whole piece
at one time. Matches, so used, are called leaders, and are generally
confined in paper tubes.
Cotton is one of the best applications to recent burns. Applied to
the part, it will, in a surprising manner, abate the violence of the
pain, and remove the inflammation.
Cotton is soluble in alkaline ley. For some of the earths, it has a
strong affinity, particularly alumina; as also for several metallic
oxides, and tannin. The action of mordants, in dying of cotton-goods,
depends on these affinities. Nitric acid converts it into oxalic acid.
Cotton wick for lamps, candles, &c. is rendered very inflammable by
spirit of turpentine. By dipping the end of the wick in turpentine,
the candle will inflame at once, the moment flame is applied. For
candle-making, the wick is sometimes dipped in a solution of camphor
in spirits, or in a melted mixture of camphor and wax. See _Candle_.
_Sec. LIII. Of Bone and Ivory._
Bone, which is considered to be a combination of phosphate of
lime, gelatinous matter, animal oil, &c. is used occasionally in
fire-works. By destructive distillation, bones, or osseous matter,
afford ammonia, Dippel's animal oil, &c.; and, when consumed by
fire, leave a white ash, which is composed principally of phosphate
of lime. Bone-ash is the result of the combustion of bone; for,
while all the gelatinous substance, oil, &c. are burnt off, that,
which composes the basis of bone, and which distinguishes it from
_gristle_, remains in the form of ash. Bone-ash furnishes phosphorus
by a certain process. See _Phosphorus_. Diluted muriatic acid will
take up the phosphate of lime of bone and leave the gelatin. This
mode is recommended for the separation of gelatin from bone.
Bones, when carbonized in the same manner as wood, furnish what is
called _bone-black_, but commonly known by the name of _ivory-black_.
It is nothing more than animal charcoal.
In Pyrotechny, bone, in the form of raspings, is employed to
communicate a _lustre_ to the flame of gunpowder; but, for this
purpose, the most compact, and that, which contains the least
gelatin, is usually employed. Hence _ivory_ is preferred. Ivory, in
the form of raspings, communicates to flame a bright silver colour;
and, on that account, is preferred to all other kinds of bone. The
compositions, into which it enters, will be mentioned in a subsequent
part of the work.
Ivory is the tusk, or tooth of defence, of the male elephant, and is
an intermediate substance between bone and horn, not capable of being
softened by fire. The finest and whitest ivory comes from the island
of Ceylon. The tooth of the sea-horse is said to approach to ivory,
properly so called. It is, however, harder, and, for that reason,
preferred by dentists for making artificial teeth. The coal of ivory
is remarkably black; but the so called ivory-black, sold in the
shops, is nothing else than bone-black.
Bone and ivory may be stained of various colours. One hundred parts
of ivory contain,
Gelatin, 24
Phosphate of lime, 64
Carbonate of lime, 0.1
One hundred parts of ox-bone gave
Gelatin, 51
Phosphate of lime, 37.7
Carbonate of lime, 10
Phosphate of magnesia, 1.3
Berzelius, however, detected in bone-fluate of lime, muriate of soda,
and uncombined soda. Albumen is most generally present. One hundred
parts of bone are reduced by calcination to sixty-three. One hundred
parts of human bone afforded Berzelius 81.9 phosphate of lime, 3
fluate of lime, 10 lime, 1.1 phosphate of magnesia, 2 soda, and 2
carbonic acid.
_Sec. LIV. Of Galbanum._
Galbanum is a gum-resin, obtained from the _bubon galbanum_, a plant
peculiar to Africa. It is at first a juicy fluid, which exudes when
the plant is cut above the root, and hardens by exposure to the air.
Alcohol dissolves about three-fifths of it. It contains some volatile
oil.
The only instance we know of, in which galbanum has been used in
fire-works, is in the composition of rain-fire, employed as an
incendiary, before the present _fire-stones_ were invented. The
rain-fire, which may be found in the fourth part of this work, it
is said, gave rise to the composition of fire-stone. There is no
advantage, however, in using galbanum for this purpose; since pitch,
tar, turpentine, and many other substances are more inflammable,
and, therefore, better adapted for such compositions. We mention it
merely because it was one of the ingredients in that once celebrated
incendiary preparation, the fire-rain of Siemienowicz.
_Sec. LV. Of Tow and Hemp._
In military fire-works, tow and hemp are much used, and principally
for the preparation of incendiary works. Both tow and hemp are
employed in forming match. Although old rope, &c. are used for
immersion in the tourteaux, carcass, or fire-stone composition, which
is readily imbibed, if the rope is untwisted and beaten; yet tow or
hemp is a better material, and receives more of the composition. The
manner of using it may be seen by referring to the composition for
fire-stone. For very nice purposes, the tow or hemp should be well
dressed. Flax is, therefore, to be preferred in such cases.
_Sec. LVI. Of Blue Vitriol._
Different preparations of copper are used in fire-works, to
communicate colour to the flame; and besides copper filings, brass
filings, verdigris, and the oxides of copper, the sulphate of copper,
or blue vitriol, has been employed. We may observe here, that there
are three sub-species of this salt; the bisulphate, sulphate, and
sub-sulphate, the first properly speaking being the blue vitriol of
commerce.
The sulphate, although recommended in some of the old formulæ for
coloured fire, is not, however, preferable to some other preparations
of copper. The use and application of copper, and its preparations,
will be seen in the article on coloured fire.
When sulphate of copper is heated, it is converted into a
bluish-white powder. If the heat be increased, the acid is expelled,
and the black oxide of copper remains. Before it is used, it is
exposed to heat to expel the water of crystallization. It ought to
be in the state of impalpable powder. It is composed of 33 acid, 32
oxide, and 35 water. It is decomposed by the alkalies and earths, the
alkaline carbonates, borates, and phosphates, and several metallic
salts.
The oxide may be obtained very readily from this salt, for the
purpose of fire-works, by dissolving it in water, and adding a
solution of caustic potassa; collecting the precipitate, and drying
it in a moderate heat. This will expel the water that may be
contained in it; as metallic precipitates, made in this way, are more
or less in the state of hydrates.
When metallic copper is required, it may be obtained in fine powder,
and very expeditiously, by immersing a plate of iron in a solution
of any of the salts of copper, as the sulphate. It will precipitate
on the iron, and gradually fall to the bottom of the vessel. This
metallic copper will be found to be much more impalpable than the
filings, however fine, and, for that reason, may be mixed more
accurately with different substances.
Copper burns with a beautiful green flame, and deposites a loose
greenish-gray oxide. The ammonia-oxalate of copper, of which there
are three sub-species, burns with flame.
_Sec. LVII. Of Nitrate of Copper._
This preparation of copper is used in some fire-works. It
communicates a green colour to flame. When combined with carbonaceous
substances, the combustion is vivid. This is owing to the
decomposition of the nitric acid, (in the same manner as the acid of
nitrate of potassa and other nitrates is decomposed), during which
carbonic acid and deutoxide of azote are produced. Nitrate of copper
has been more particularly recommended for the preparation of match
stick, similar to that of M. Cadet, and of match rope. It is used in
the same manner as the nitrate of lead. M. Proust used it in lieu of
nitrate of lead when repeating some experiments of M. Born. It is
more expensive than the acetate, or even the nitrate of lead. Its
effect, however, is the same.
Nitrate of copper attracts the moisture of the atmosphere, and
deliquesces. Acetate of lead, on the contrary, by exposure to the air
gradually effloresces, and in time is decomposed. The preparations of
lead, for that reason, are preferable to the nitrate of copper.
Nitrate of copper is formed by dissolving copper in nitric acid; and,
when the acid is saturated, the requisite quantity of water may be
added. The salt may be obtained in a dry state by evaporation; and,
after being dissolved in water, the wood or rope may be soaked in it.
Dry nitrate of copper, wrapped up in tin-foil, will produce no
action; but, if water be added, sufficient to moisten it, and then
the foil closed tightly, combustion will take place. The water
promotes chemical action by dissolving the nitrate of copper, which
is then decomposed by the tin, and the quantity of caloric, put in a
distributable state, is sufficient to inflame the tin. The details of
the rationale will be given hereafter.
The ammonia-nitrate of copper is fulminating copper. The chlorate of
copper is a deflagrating salt. Ammonia added to nitrate of copper,
first separates an oxide, and then dissolves it. It is more than
probable, that nitrate of ammonia causes the ammonia-nitrate to
explode.
_Sec. LVIII. Of Strontia._
The earth called strontia or strontian, is found abundantly in
different parts of the world, in combination with carbonic and
sulphuric acids. The carbonate of strontia or strontianite,
effervesces with acids, and burns with a purple flame. It contains
about 60 or 70 per cent. of earth. The sulphate of strontia, or
celestine, contains about 57 of strontia.
When carbonate of strontia is mixed with charcoal powder, and exposed
to a heat of 140° of Wedgwood's pyrometer, the carbonic acid will
be expelled, and pure strontia remain. The earth may be obtained
in a pure state, by dissolving the carbonate in nitric acid, and
evaporating the solution until it crystallizes, and exposing the
crystals, in a crucible, to a red heat, until the nitric acid is
driven off. If the carbonate cannot be had, the sulphate may be
employed. For this purpose, it is to be pulverized and mixed with
an equal weight of carbonate of potassa, and boiled in water. The
carbonate of strontia, thus obtained, which exists in the form of a
powder, is to be treated with nitric acid as already described.
Strontia, like the other earths, is a compound body, having a
metallic basis, called _strontium_, which, united with oxygen, forms
the earth.
The specific gravity of strontia approaches that of barytes. Like
pure barytes, it is soluble in water, forming strontia water. It
requires rather more than 160 parts of water at 60° to dissolve it;
but much less of boiling water.
The solution of strontia in water, when evaporated, will crystallize
in thin, transparent, quadrangular plates, generally parallelograms,
seldom exceeding a quarter of an inch in length. These crystals
contain about 68 per cent. of water; and are soluble in little
more than twice their weight of boiling water, and in 54.4 times
their weight of water at 60°. When dissolved in alcohol, they give
a blood-red colour to its flame. The solution of strontia changes
vegetable blues to green. Strontia differs from barytes in being
infusible, much less soluble, of a different form, weaker in its
affinities, and not poisonous.
The metallic base of strontia, which was discovered by Sir H. Davy,
in 1808, when exposed to the air, or when thrown into water, rapidly
absorbs oxygen, and is converted into strontia.
As strontia communicates a red colour to flame, it has been used in
certain compositions of artificial fire. The brilliant red fire,
sometimes used in theatres, owes its colour to this earth. See
_Theatrical fire-works_. Muriate and nitrate of strontia will give a
red or purple colour to the flame of alcohol. See _coloured flame of
alcohol_.
If a piece of cloth be dipped in a solution of muriate, nitrate,
or acetate of strontia, or in strontia water, and then immersed in
alcohol, it will burn with a red flame.
M. Fourcroy, (_Système des Connaissances Chimiques, &c._ tome iii,)
mentions the use of nitrate and muriate of strontia, in artificial
fire-works, for the purpose of communicating a red colour to the
flame of combustible bodies. Since that time, the nitrate, in
particular, has been recommended and used.
One of the characters of the salts of strontia, is, that they give a
red flame to burning bodies; whereas the salts of barytes or of lime,
used in the same manner, communicate a yellow flame.
The saline combinations of strontia were examined with particular
attention by Dr. Hope. See _Edinburg Philosoph. Transactions_ for
1790.
Nitrate of strontia may be formed by dissolving carbonate of
strontia, or the sulphuret obtained by decomposing the sulphate by
charcoal, in nitric acid, filtering the solution, evaporating it, and
suffering it to crystallize.
Nitrate of strontia deflagrates on ignited coals. Dr. Hope pointed
out, that if nitrate of strontia be exposed to a red heat, and a
combustible substance be, at this time, brought in contact with
it, a deflagration, with a very vivid red flame, will be produced.
When a crystal of this salt is put into the wick of a candle, it
communicates a beautiful purple flame. It does not deliquesce in the
air, and, therefore, the compositions, into which it enters, cannot
spoil on that account. Nicholson (_Chemical Dictionary_,) observes,
that nitrate of strontia may be used in the art of pyrotechny.
For this purpose, however, it is mixed with sulphur, chlorate of
potassa, and sulphuret of antimony; and sometimes with the addition
of sulphuret of arsenic and charcoal, as in the _red fire_ for
theatrical uses.
The muriate of strontia has similar properties. Davy first observed,
that when strontia was heated in chlorine gas, it gave out oxygen
gas, and a chloride of strontium was formed.
Muriate of strontia is formed very readily, by dissolving the
carbonate or sulphuret of strontia in muriatic acid, and evaporating
the solution in order to obtain crystals. These crystals are very
soluble in water. They are soluble, also, in twenty-four times their
weight of pure alcohol, at the temperature of 60°. This alcoholic
solution, we remarked, burns with a fine purple colour. These
crystals suffer no change when exposed to the air, except they be
very moist; in which case, they deliquesce. When heated, they first
undergo the watery fusion, and are then reduced to a white powder.
Fourcroy recommends the muriate of strontia for fire-works.
Carbonate of strontia, when thrown in powder on burning coals,
produces red sparks.
Acetate of strontia, another salt used in fire-works, is formed
by dissolving strontia, or its carbonate, in acetic acid. It will
crystallize. The crystals are not affected by exposure to the air.
When heated, its acid is decomposed, as happens to all the other
acetates.
_Sec. LIX. Of Boracic Acid._
Borate of soda, or borax, is a salt, which has long been known, and
is used chiefly in the arts as a flux for the fusion of bodies, and
for soldering. Boracic acid is a compound body, consisting of a newly
discovered substance, called boron, and oxygen. Homberg obtained
the acid from borax in 1702, by distilling a mixture of borax, and
sulphate of iron. He supposed that it was a product of the latter;
and hence it was called the _volatile narcotic salt of vitriol_, or
_sedative salt_.
Boracic acid forms two salts with soda; the borate, properly so
called, and borax. It is supposed to be our borax, that Pliny
mentions under the name _crysocolla_, so called by the ancients.
Others, however, assert, that their crysocolla was nothing more than
the rust of copper, triturated with urine. The impure borax in the
East Indies, is called _tincal_. When borax is melted, and exposed
for some time to heat, it loses its water, and is changed into what
is known by the name of _calcined borax_.
The easiest process for obtaining boracic acid is to make a
concentrated solution of borax in hot water, and add by degrees,
sulphuric acid, which will unite with the soda; and, as the fluid
cools, the boracic acid will separate in shining laminated crystals.
No more acid should be added than is sufficient to make the solution
slightly sour. The crystals are to be washed with cold water, and
drained upon brown paper.
One of the principal characters of boracic acid is, that it is very
soluble in alcohol, to the flame of which it communicates a green
colour. Paper dipped in this solution, burns in the same manner.
In consequence of this property of imparting a green colour to
flame, I made some experiments with it, for the purpose of preparing
_green fire_; and found, that, by employing it in the proportion of
one-eighth, the flame was always green, provided that the flame of
the combustible used, was not tinged of any other colour. Nitre,
charcoal, and boracic acid will give a green; also nitre, lamp oil,
and boracic acid; nitre, alcohol, and boracic acid, along with
charcoal; and chlorate of potassa, charcoal, and boracic acid, with
or without the addition of alcohol. But, although boracic acid
communicates a lively green, its expense will prevent its use in that
way, especially as many other preparations, as those of copper, will
have the same effect, and are more economical on account of their
price. See the _Coloured Flame of Alcohol, and Coloured Fire_.
Oils, when assisted by heat, will dissolve boracic acid. In naphtha,
it is very soluble. With oils, it yields fluid and solid products,
which give a green colour to the flame of alcohol. It is not a
combustible acid, but only imparts colour to the flame of combustible
bodies.
Boron will unite with fluorine, the radical of fluoric acid. When
one part of vitrified boracic acid, two of fluate of lime or fluor
spar, and twelve of sulphuric acid are distilled, an acid gas will be
obtained, called fluo-boric gas. For the properties of boron, consult
Thenard's _Traité de Chimie_.
PART II.
INSTRUMENTS, TOOLS, AND UTENSILS.
CHAPTER I.
OF THE LABORATORY.
The laboratory for pyrotechny may consist of a building, furnished
with furnaces, boilers, &c. for the preparation or refining of
saltpetre, and other substances for use; but according to its
present acceptation, it is a place where all kinds of fire-works
are prepared, both for actual service and for exhibition; such as,
besides the ordinary works for show, quick matches, fuses, port-fire,
grape-shot, case-shot, carcasses, hand granades, cartridges, &c. It
should have tables, benches, and closets, where the tools, paper,
thread, &c. may be commodiously placed, and an adjoining room to
contain a supply of materials for two days' work.
The chief artificer takes the weight of the materials made use of,
attends to the weighing of the different substances, and sees that
the mixtures are made properly, &c. He also keeps an account of the
number and kinds of fire-works. The prepared fire-works ought to be
removed daily to the magazine. If they are made up in the field,
under a tent, (denominated the _Laboratory tent_,) they should be
packed in barrels or in caissons.
_Sec. I. Of Laboratory Tools and Utensils._
The following constitute the furniture and equipments of a laboratory:
Copper rods, to load port fires, and the fuses of shells,
howitzers, &c.
Wooden formers, on which to roll the paper cases of the port
fires.
Wooden formers, to roll the cases of rockets.
Balances, large and small, with weights, &c.
Buckets to carry water.
Boxes for loading priming tubes.
Barrels with leather tops, that draw, in order to keep grained
and meal gunpowder.
Rods, or rammers for charging rockets.
Brushes to wipe the tables and sweep the compositions together.
Frames to dry priming tubes.
Copper calibers to regulate the size of priming tubes.
Penknives.
Needles for piercing priming tubes in the direction of their
length.
Fuse drivers.
Coopers' adzes.
A copper kettle.
Scissors for cloth and paper.
Paper cutters.
Priming wires.
Skimmers for skimming the froth of boiling saltpetre.
Funnels for charging port-fires, howitzers, shells, &c.
Square ruler.
Fuses for shells, &c. (or a lathe to make them.)
Large and small wooden bowls.
Small axes.
Ladles for charging the fuses of shells, port-fires, &c.
Mallets to hammer the fuses.
Glue pots and brushes.
Heavy mallets to beat the powder.
Tin measures, of different sizes.
Hand mortar.
Foot rules.
Rat-tail files to cleanse the interior of the reeds of priming
tubes.
Wooden rasps.
Iron rulers, 1/2 foot long.
Leather bags, in which gunpowder and charcoal are reduced
to powder.
Pocket saws.
Pallet knives for saltpetre.
Tables, small ones to mix the composition; large ones with
a ledge to meal the powder on.
Sieves, fine and common; of silk, and of hair.
Fuse drawers.
Tools for rolling cartridges.
Gimblets of different sizes.
The materials required more particularly for military fire-works, are:
Gunpowder.
Saltpetre.
Sulphur.
Charcoal.
Camphor.
Beeswax.
Glue, rosin.
Cotton yarn for quick match.
Brandy or other spirits.
Gum arabic.
Linseed oil.
Spirits of turpentine.
Pitch.
Reeds or quills for priming fuses.
Mutton tallow.
Vinegar.
Thread for tying quick match.
Cartridge paper.
Thread, tow and spun yarn, to make match rope.
Cordage, to make tourteaux.
Flour to make paste.
The characters used to express certain substances employed in
fire-works, are the following: (_James's Mil. Dict._ p. 101.)
M. means meal powder,
⊝. Saltpetre.
C. Z. Crude sulphur.
C. S. Sea coal.
S. x Steel or iron filings.
G. x Glass dust.
C. I. Cast iron.
X. Camphor.
B. L. Lampblack.
L. S. Lapis Calaminaris.
W. Spirits of wine.
P. O. Oil of spike.
∋. Corn powder.
Z. Brimstone.
C. + Charcoal.
B. R. Beech raspings.
B. x Brass dust.
T. x Tanners' dust.
C. A. Crude antimony.
A. Y. Yellow amber.
G. I. Isinglass.
⩀. Gum.
S. T. Spirits of turpentine.
_Sec. II. Of Mandrils and Cylinders for forming Cartridges and Cases._
The rollers or rods, on which cartridges are formed, ought to be
solid, and perfectly straight and round. Very dry, sound wood
should be selected, and when turned, the rod should be perfectly
cylindrical; one extremity being concave, and the other convex.
Mandrils may be made of copper, which is preferable to wood, as this
is apt to warp and crack; and in both cases, should be longer than
the cartridge, so as to be drawn out easily. They are of different
lengths and diameters, according to their respective uses.
_Sec. III. Of Rammers, Chargers, and Mallets._
The rammers which are used for compression, are cylindrical like
the preceding. They have a head much larger in dimensions than the
part that enters the tube. (See A, B, C, D, and E of Fig. 1. in the
Plate). Besides being made of wood, which should be of the hardest
kind, as _lignum vitæ_, they may be formed of copper or brass. In
this case, they are first cast of the requisite size and shape, and
finished in a lathe. Wooden heads are sometimes put to them, but with
little advantage; as they frequently split and require to be renewed.
The wooden rammer may be struck with metal; but when the rammer is of
copper or brass, wooden mallets must be always employed.
We may here remark, that in charging rockets, it has been customary
to employ several rammers. The first _drift_ must be six diameters
from the handle, and this, as well as all other rammers, ought to
be a little thinner than the former, to prevent the tearing of the
paper, when the charge is driven in. In the end of this rammer is a
hole to fit over the piercer. (See B. Fig. 1.) The line marked on
this rammer, as will be explained hereafter, when it appears at the
top of the case, indicates that a second rammer must be used. This
second rammer, from the handle, is four diameters, having a hole for
the piercer, 1-1/2 diameters long. (C. Fig. 1.) When the case is
filled as high as the top of the piercer, a short and solid drift is
used. (E. Fig. 1.).
Rammers must have a ferrule, or collar of brass at the bottom, to
keep the wood from spreading, or splitting. With regard to the
handles of the rammers, if their diameter be equal to the bore of
the mould, and two diameters long, the proportion is a good one. The
shorter they can be used, the better. The longer the drift, the less
of course, will be the pressure on the composition, by the blow given
by the mallet.
We may observe here, that rockets may either be driven over a
piercer, or driven solid, and afterwards bored.
As much of the effect of rockets depends upon the manner they are
driven, whether lightly or compactly, or uniformly throughout,
circumstances which affect their quality; it is necessary, in using
the rammer, to employ an equal force for driving the composition.
The mallet, therefore, should be of a given weight; and a certain
number of strokes with the same force, on each new charge, must be
accurately followed, until the driving is completed; taking care, at
the same time, that the rocket stands firm on a solid body.
Dry beech is the best wood for mallets. A writer very judiciously
observes, in the _Encyclopedia Britannica_, (vol. xv, 695), that,
if a person uses a mallet of a moderate size, in proportion to the
rocket, according to his judgment, and if the rocket succeeds, he
may depend on the rest, by _using the same mallet_; yet it will be
necessary, that cases of different sorts, be driven with mallets of
different sizes. In all cases, under one ounce, the charge may be
rammed with an ounce mallet.
There is an advantage, also, by having the handle of the mallet
turned out of the same piece as the head, and made in a cylindrical
form. If their dimensions are regulated by the diameters of the
rockets; then, for example, if the thickness of the head be three
diameters, and its length four, the length of the handle will be five
diameters, whose thickness must be in proportion to the hand.
Bigot (_Artifice de Guerre_, p. 118) speaking of the flying fuses,
or sky-rockets, observes, that the mallet used for driving the
composition, is proportionably large, according to the rockets, and
that it is five inches in length, and four in breadth, when the
diameter of the rocket is from 12 to 18 lines. The mallets for larger
rockets are stronger and heavier, and, in some instances, where a
great force is required, as in driving war-rockets, a machine similar
to the pile-engine, is used. See _Congreve Rockets_.
_Sec. IV. Of Utensils necessary for constructing of Signal Rockets._
A detailed account of the tools used in making signal rockets, may be
seen in Ruggeri, _Pyrotechny_, p. 143; but M. Bigot has enumerated
them as follows:
One mandril for forming the cartridge, or case.
One pair of curved compasses to determine the exterior
diameter.
Three conical mandrils. (See fig. 3, plate.)
One solid, or massive cylinder.
One mould for garnishing.
Two moulds for the capitals, or heads, one of which is for
the rockets with, and the other for the rockets without,
the _garnish_, or furniture.
One piercer and block (See plate, fig. 1, I & H.)
One scoop.
One punch.
One mallet.
One press.
One large knife.
One pair of scissors.
All the wooden utensils ought to be made of hard and sound wood,
without knots. The rammers should be furnished with rings or
ferrules, and the first bored with a hole of sufficient length
to receive the piercer. The second should be bored deep enough
to receive two-thirds of the piercer, and the third, to receive
one-third, while the fourth should be solid. These rammers are all
furnished with heads. (See section iii.)
_Sec. V. Of the Rolling, or Plane Board._
This board is furnished with a handle, and is used for rolling
rocket cases, &c. and is of different dimensions, according to its
application. It is made of hard wood, such as oak or walnut.
When the paper is wrapped round the mandril or _former_, the rolling
board is used to compress the paper, and make it round and smooth.
_Sec. VI. Of the Driver for charging large Rockets._
This contrivance is similar to a pile driver in construction; and, by
means of a weight falling upon the rammer, the charge is sent home
with great force. Its use is confined to the largest kind of rockets.
_Sec. VII. Of Mortars and Pestles._
Mortars are employed for the pulverization of substances, and,
according to their use, may be either of wood, marble, brass, or
cast-iron, which last costs less than the others. Large mortars have
covers, in order to confine the finer particles. The pestles should
be of very hard wood; because, in that case, no danger would be
apprehended of an explosion of the materials, an occurrence which
might take place, if iron were used. This, however, depends on the
substances submitted to the pestle.
_Sec. VIII. Of the Choaker or Strangler._
The choaker is nothing more than a contrivance, usually made of
rope, by which the closing of the end of the rocket is effected, so
as to form a kind of cup or mouth.
_Sec. IX. Of the Table and Sack for mealing Gunpowder._
This table may be either square or an octagon, and made of hard wood.
There is a rim, a few inches high, raised round it, and a gutter
at one end to allow the powder to pass out, when the operation is
finished. See plate, fig. 7 and 8.
This mode of mealing powder is by no means to be preferred. (See
_Gunpowder_.)
A sack is also used for crushing powder. It should be made of strong
elastic leather, and sewed together in such a manner as to prevent
the impalpable powder from passing through its seams. They are of
an oblong shape, and contain from 20 to 25 pounds. Fifteen pounds
are generally put in at a time. This method of crushing powder is
preferred, as it is less liable to accidents. It is hardly necessary
to add, that the bag is beaten with a cylindrical stick.
_Sec. X. Of Sieves._
There are several kinds of sieve. The common sieve has neither a
cover nor a receiver, and may be either formed of horse hair, or of
brass or copper wire. It is necessary to have some sieves of a finer
kind. For this purpose, silk and gauze are generally used. The cover
is merely leather, fixed in a frame, which fits on the top. The
receiver is formed nearly in the same manner, having a skin stretched
over a frame, which fits on the under part of the sieve.
_Sec. XI. Of the Paper Press._
A press, for the purpose of pressing paper, is formed of two pieces
of wood, which are brought together by means of one, or several
screws. This press is sometimes, though seldom, used. If pasteboard
is made, when it cannot be had ready prepared, then the press is
actually necessary. The intention is to unite the several sheets,
which have been pasted, by using the pressure of the screw, and
to remove any extraneous paste, so that the paper may have no
inequalities on its surface. In lieu of the screw-press, heavy
weights laid on the paper for several hours, will answer the same
purpose.
CHAPTER II.
_Preliminary operations in the preparation of fire-works, and
observations on the preservation of gunpowder, and sundry
manipulations._
_Sec. I. Of the Workshop._
We have already noticed the principal furniture of a laboratory, and,
therefore, can add nothing new on this head. There are, however, some
utensils employed for particular works, which we may here describe.
In the disposition of the workshop, the tables, utensils, &c. are
arranged, according as the judgment may dictate for convenience
and use. Care must be taken to prevent the access of fire, and to
prevent, as far as possible, the presence of moisture. Lanterns, if
light is required, are always to be preferred; but the best manner of
communicating light is through a window, placing the lights outside
of the building, or apartment, as is done in powder mills. Other
precautions may be necessary, which will readily suggest themselves.
In conducting the work, the workmen are to be so arranged, as that,
while some are employed in the preliminary operations, others are
making and finishing the preparations. The compositions may be ready
prepared, and well preserved in jars or other vessels. This is named
by the French, _Cabinet de composition_. It is a place, also, where
the substances are weighed, and mixed.
_Sec. II. Of the Magazine._
The magazine is a place of deposite for gunpowder, to preserve it
from fire, and moisture. We have already mentioned the preservation
of gunpowder in the article on that subject; but it may not be
improper to offer some remarks, respecting the construction of
magazines.
Authors differ in opinion, both in regard to their situation and
construction; but they all agree, that they ought to be arched,
and bomb-proof. The first powder magazines were made with gothic
arches: Vauban constructed them in a semicircular form, to make
them stronger. Their dimensions were, sixty feet long, within, and
twenty-five broad. The foundations were eight or nine feet thick, and
eight feet high, to the spring of the arch. The floors were two feet
from the ground, for the purpose of keeping the magazine free from
dampness.
It is observed, that the centres of semicircular arches will settle
at the crown, and their sinking must break the cement. A remedy was
applied for this inconvenience, by the _arch of equilibration_, as
described in Hutton's work on bridges. As, in powder magazines,
the ill effect of the breaking of the cement is particularly felt,
Mr. Hutton proposed to find an arch of equilibration for them in
particular, and to construct it, when the span is twenty feet,
the pitch or height, ten, (which are the same dimensions as the
semicircle), the inclined exterior walls at top, forming an angle of
113 degrees, and the height of their angular point, above the top of
the arch, equal to seven feet.
A wall built round a magazine, gives it an additional security. The
roof should be slated, or covered with lead or copper, and it ought
to be furnished with a lightning rod, placed ten or fifteen yards
from the building. The points of the rods may be either gilt, or
of solid gold. Silver, however, is generally used; but, above all,
platinum is to be preferred. The advantage of these points is, that
they do not rust like iron, or become oxidized, an occurrence which
would diminish their powers as conductors of the electric fluid.
To prevent the access of moisture, or rather to absorb it, some have
recommended the inner walls to be covered with a composition of
powdered coal, &c. Lining of magazines with sheet lead, appears to
have some advantages.
St. Pierre observes, that a Prussian officer informed him, that,
having remarked that vapour was attracted by lead, he had employed
it for drying the atmosphere of a powder magazine, constructed
under ground, in the throat of a bastion, rendered useless from its
humidity. He ordered the concave ceiling of the arch to be lined with
lead, where the gunpowder was deposited in barrels: the vapour of the
wall collected in drops on the leaden roof, ran off, and left the
gunpowder barrels perfectly dry.
_Sec. III. Of the Driving or Ramming of Sky-rockets._
We purpose in the present article to give some general directions for
the driving of rockets.
Rockets may be driven solid, or over a piercer. In the latter case,
they must not have so much composition put in them at a time. The
piercer, accompanying a greater part of the bore of the case, would
cause the rammer to rise too high; so that the pressure of it would
not be so great on the composition, nor would it be driven equally.
For rockets rammed over a piercer, let the ladle, or copper scoop,
hold as much composition, as, when driven, will raise the drift
one-half the interior diameter of the case; and, for those driven
solid, let it contain as much as will raise the drift one-half the
exterior diameter of the case. Ladles are generally made to go easily
into the case, and the length of the scoop is about one and a half of
its own diameter.
The charge of rockets must always be driven one diameter above the
piercer, and, on it, must be rammed, one-third of a diameter of
clay; through the middle of which a small hole must be bored to the
composition, so that, when the charge is burnt to the top, it may
communicate its fire, through the hole, to the stars in the head.
(See plate, fig. 14.) Great care must be taken to strike, with the
mallet, with an equal force, giving the same number of strokes to
each ladleful of composition; otherwise the rocket will not rise with
a uniform motion, or burn equally and regularly, for which reason,
they cannot carry a proper tail. It will break, in this case, before
the rocket has ascended to its extreme height, where the rocket
should break and disperse the stars, rain, or whatever is contained
in the head. When in the act of ramming, the drift or driver must
be kept constantly turning or moving; and when the hollow rammers
are used, the composition is to be knocked out every now and then,
or the piercer will split them. To a rocket of four ounces, give to
each ladleful of charge, 16 strokes; to a rocket of 1 lb. 28; to a
2 pounder, 36; to a 4 pounder, 42; to a 6 pounder, 56. But rockets
of a larger sort cannot be driven by hand, and must be rammed with a
machine similar to a pile-driver.
The method of ramming wheel cases, or any other sort, in which
the charge is driven solid, is much the same as that used for
sky-rockets; for the same proportion may be observed in the ladle,
and the same number of strokes given, according to their diameters,
all cases being distinguished by their diameters. In this manner,
a case, whose bore is equal to that of a rocket of four ounces, is
called a four ounce case; and one which is equal, in bore, to an
eight ounce rocket, an eight ounce case, &c. The method of ramming
cases, without moulds, will answer for strong pasted cases, and save
the expense of making so many moulds. In filling any case, it must be
placed on a perpendicular block of wood, in order to keep it firm and
solid; otherwise the composition would be rammed unequally.
When cases are to be filled without moulds, procure some nipples,
made of brass or iron, in proportion to the cases, to screw or fix
in the top of the driving block. When the nipple is fixed in, make,
at about one and half inches from it, a square hole in the block,
six inches deep, and one inch in diameter. Then have a piece of
wood, six inches longer than the case intended to be filled, and two
inches square. On one side of it, cut a groove, almost the length
of the case, whose breadth and depth must be sufficient to cover
near one-half the case. Then cut the other end, to fit the hole in
the block; but take care to cut it, so that the groove may be at a
proper distance from the nipple. This half mould being made, and
fixed tight in the block, cut, in another piece of wood, nearly of
the same length as the case, a groove of the same dimensions as that
in the fixed piece. Then put the case on the nipple, and, with the
cord, tie it, and the two half moulds together; and the case will be
prepared for filling. The dimensions of the above half moulds are
proportionable for cases of eight ounces; but they differ in size in
proportion to the cases.
_Sec. IV. Of the Boring of Rockets._
The machine, for boring rockets, is similar, in some respects, to a
lathe. The rocket is confined in a box, and, by means of a wheel,
which is made to turn a second one, an auger rammer is put in motion.
The rammer must be of a size, proportionate to the rocket, and of
the same diameter, as the top of the bore intended, and continue of
that thickness, a little longer than the depth of the bore required.
The thick end of each _rammer_ must be made square, and all of the
same size. The rammer is made to move backward, and forward, so that,
after the rammer is marked three and a half diameters of the rocket,
from the point, set the guide, allowing for the thickness of the
front of the rocket box, and the neck and mouth of the rocket. When
the rocket is fixed in the box, it must be pushed forward against the
rammer, and, when the scoop of the rammer is full, draw the box back,
and knock out the composition. A little oil is sometimes used, to
prevent the friction from setting fire to the rocket. Having bored a
number of rockets, taps must be used. These taps are similar to the
common spicket. When employed, it is necessary to mark them three and
a half diameters from the point, allowing for the thickness of the
rocket's neck.
There are several contrivances for the boring of rockets. The
operation is sometimes done, by confining the rocket in a box, and
boring it with a borer, fixed in a brace, using, at the same time,
a proper director. This brace is like the common _brace_, used by
carpenters, or formed on that principle, and made of iron. The
motion, given by the hand, performs the operation.
_Sec. V. Of the Preservation of Steel or Iron Filings._
When treating of iron, we mentioned, that it has the property of
oxidizing rapidly, when exposed to the air and moisture; and that its
effects in fire-works, in that case, would be either destroyed, or
considerably diminished. And even fire-works, in which iron enters as
a component part, will, if kept long, lose some of their effect, in
consequence of the change, which the iron suffers; for, instead of
producing brilliant sparks, which is their intention, it would impart
a dull red appearance.
Two methods are recommended for the preservation of iron. The one
is to melt a portion of sulphur, and throw the filings into it, and
afterwards to separate the extraneous sulphur. The other consists
in wrapping them up in oiled paper. As to the first method, we may
apprehend the effect of the sulphur, combining with some of the iron,
instead of coating it, forming thereby a sulphuret, which, besides,
is readily decomposed by the contact of air and moisture, producing
sulphate of iron. The second method, of wrapping them in oil, or, in
fact, covering them with oil, is certainly a greater preventive from
rust, for where the oil is in contact, no oxidizement can take place.
There are several methods recommended to preserve iron-work from
rusting. The use of paint and varnish for this purpose is familiar.
In Sweden, they cover iron-work with a mixture of pitch, tar, and
wood soot, which acquires a gloss, similar to that of varnish, and
is said to prevent the oxidizement of the metal very effectually.
Fat-oil varnish, mixed with four-fifths of rectified spirit of
turpentine, has been recommended. It is applied with a brush, or
sponge. Articles, varnished with this preparation, are said to retain
their metallic brilliancy, and never contract any spots of rust.
Another composition, for the same purpose, is highly recommended. It
consists in applying a mixture of one pound of hogs' lard, free from
salt, one ounce of camphor, two drachms of black lead in powder, and
two drachms of dragon's blood. At Sheffield and Birmingham, sundry
articles, made of steel and iron, are preserved from rust, when sent
to foreign markets, by wrapping them in coarse brown paper, prepared
first with oil.
Among the different preparations, recommended at various times to
prevent iron from contracting rust, we may mention one, which has
been used with success, and which gives a lead colour. It is nothing
more than taking some litharge, and heating it in an iron pot, and
scattering over it some sulphur. The litharge will change its colour,
forming a kind of sulphuret of lead, which is then ground with drying
oil, and applied like paint. We are told, that this preparation gets
remarkably hard, and resists the weather more effectually than any
other lead colour.
_Sec. VI. Of the making of Wheels and other Works incombustible._
It is usual to give a coat of paint to the wood-work of wheels, &c.
which are designed to carry a number of cases. To prevent their
taking fire, paint, in some measure, has the effect. The following
composition is recommended: Take brick dust, coal-ashes, and iron
filings, of each an equal quantity, and mix them with a double size,
made hot. Apply this to the wood, and when dry, give it another coat.
Several methods have been adopted for the same purpose; but wood
may be made to resist, in a great degree, the action of fire, and
rendered almost incombustible, by soaking it in a solution of the
supersulphate of potassa and alumina, (alum), in sulphate of iron,
(green vitriol), and in other salts, which are incombustible.
With respect to the use of alum as a preservative against fire, it
is certain, that, although its use in this way is very ancient, it
was not often recommended; for writers on the art of war, such, for
example, as Anas, mentions the use of vinegar, in the following
quotation from his _Poliorcet._ cap. 24: "Majus juverit, si prius
ligna aceto linantur; nam a materia aceto illita, ignis abstinet."
The use of alum, to prevent substances from taking fire, is not a new
invention; notwithstanding we find it recommended in modern works,
not only for wood, but also for paper, and linen and cotton dresses,
&c. Aulus Gellius relates, that Archelaus, one of the generals of
Mithridates, washed over a wooden tower with a solution of alum, and
thereby rendered it so much proof against fire, that all Sylla's
attempts to set it in flames proved abortive.
A writer in the _Anthologia Hibernica_, vol. iii, for 1794,
observes, that the use of alum to prevent the action of fire, on
wood, or other combustible bodies, is not new, and those, who lay
claim, are not entitled to originality on that head.
Another mode to prevent wood from taking fire may also be adopted. It
consists in mixing together, one ounce of sulphur, one ounce of red
ochre, and six ounces of green vitriol. The wood work is covered with
joiners' glue, and the mixture is then put over it. This process is
to be repeated three or four times, allowing the glue to dry before a
new coat is applied.
There are several other preparations for the same purpose, not only
for the covering of wood, but also paper. But M. Ruggeri is of
opinion, that they cannot be depended upon, when used on paper; for
the paper will, in part, be consumed. The formula for one of these
compositions, is thus given by that gentleman: To a pound of flour,
mix a handful of powdered alum, and add to it strong glue-water, and
bring it to a proper consistence with clay. Flour and glue-water,
mixed together, with the addition of a small quantity of muriate
of soda, (common salt), is also recommended for the same purpose.
Wood, steeped in a solution of common salt, so as to be thoroughly
impregnated with it, is very difficult of combustion. In Persia, salt
is used to prevent timber from the attack of worms. The practice of
_salting_ ship timber is highly recommended.
Wood, in fact, may be rendered incombustible by several processes,
some of which we have given. Earl Stanhope, among others, made some
interesting experiments on this subject.[23]
Having thus given some of the modes, usually adopted to render wood
incombustible, or to prevent its taking fire so instantaneously, we
purpose to add some remarks respecting the processes for colouring
it. An excellent preservation against moisture, which communicates
a colour at the same time, is formed of 12 lbs of rosin, 3 lbs
of sulphur, and 12 pints of whale oil, melted and mixed with a
sufficient quantity of red or yellow ochre, and applied by means of
a brush. Pulverized black lead may be substituted for the ochre.
Several coats of this mixture may be put on, allowing each coat to
dry before another is applied. This composition is particularly well
adapted for wheel work, &c. and for aquatic fire-works. Chaptal
advises, for the same purpose, a mixture of equal parts of white
turpentine, bees' wax, and maltha, or, in the place of maltha, coal
tar. Wood, covered with three coats of this composition, and immersed
for two years in water, was found to be quite dry. It would be well,
however, to cover it with some of the preparation, to render wood
incombustible.
With respect to the staining of wood of various colours, several
preparations may be used. To communicate a green colour, a hot
solution of acetate of copper may be used; or verdigris, alum, and
vinegar, boiled together. A decoction of brazil wood, with alum and
cream of tartar, will impart a red; indigo, dissolved in sulphuric
acid, (liquid blue dye), a blue; a decoction of logwood, nut-galls,
and copperas, a black; a solution of dragon's blood, or of alkanet
wood, in turpentine, a mahogany colour, &c. The imitation of bronze
on wood may be effected, by covering it first with isinglass size,
then suffering it to dry, and putting on a coat of oil gold size, and
covering it with bronze powder, a preparation sold for that purpose.
A solution of aloes in spirits, which communicates a greenish-black,
is a great preservative of wood against worms.
M. Ollivier (_Archives des Découvertes_, v, p. 386) has given a
variety of recipes for imitating bronze, stone, &c. He recommends the
following for the imitation of ancient bronze, which may be applied
to wood-work. Melt together 150 lbs of fine sand, 170 lbs of lead
ore, (Galena), and 30 lbs of manganese, and add one-sixth part of
brass. This compound is then pulverized. It is applied on the usual
ground.
_Black earth_, as it is called, made of green earth, oxide of
manganese, oxide of iron, and oxide of copper, is also recommended
for covering wood-work. The composition for _imitation marble_, is 1
part of green earth, 1/2 a part of sand, and 1/8th of a part of bol.
armen. By adding 1/14th part of _yellow burnt copper_, the colour
will approach to green. The same composition, with 1/16th part of
copper, and 1/32d iron, will give a black.
_Sec. VII. Of the formation of Rocket, and other Cases._
The cases for rockets, as a general rule, are to be made 6-1/2 times
their exterior diameter in length; and all other cases, that are to
be filled in moulds, must be as long as the moulds, within a half of
the interior diameter. Rocket cases, from the smallest, to 4 or 6
pounds, are generally made of the strongest sort of cartridge paper,
and rolled dry; but the large sort are made of pasted pasteboard.
(See observations on that subject.) As it is very difficult to roll
the ends of the cases quite even, the best way is to keep a pattern
of the paper for the different kinds of cases. These patterns should
be longer than the case they are designed for, and the number of
sheets required should be marked, which will prevent any paper being
cut to waste. Cut the paper of a proper size, and the last sheet
for each case, with a slope at one end; so that when the cases are
rolled, it may form a spiral line round the outside; and that this
slope may always be the same, let the pattern be so formed for a
constant guide. Before you begin to roll, fold down one end of the
first sheet so far, as that the fold will go two or three times round
the former; then, in the double edge, lay the former with its handle
off the table, and after rolling two or three turns, lay the next
sheet on that which is loose, and roll it all on.
The smoothing board, which is about twenty inches long, is now to
be applied; and after rolling the paper three or four times, lay
on, in the same manner, another sheet of paper, and smooth it in
the same manner. This operation is to be repeated till the case is
sufficiently thick. When the last sheet is rolled, we must observe,
that the point of the slope is placed at the small end of the roller.
The case being made, the small end of the former is put in, to about
one diameter of the end of the case, and the end piece is inserted
within a little distance of the former. Then give the pinching cord
one turn round the case, between the former and the end piece. At
first, pull easy, and keep moving the case, which will make the neck
smooth, and without large wrinkles. This operation is called by the
French _strangling_, or _choaking_. When the cases are hard to choak,
let each sheet of paper (except the first and last in that part where
the neck is formed) be a little moistened with water. Immediately
after you have struck the concave stroke, bind the neck of the case
round with small twine, which must not be tied in a knot, but
fastened with two or three hitches.
Having thus pinched and tied the case, so as not to give way, put
it into the mould without its foot, and, with a small mallet, drive
the former hard on the end piece, which will force the neck close
and smooth. When this is done, cut the case to its proper length,
allowing, from the neck to the edge of the mouth, half a diameter,
which is equal to the height of the nipple. Then take out the former,
and drive the case over the piercer with the long rammer, and the
vent will be of a proper size.
Wheel cases are sometimes driven on a nipple, with a point to close
the neck, and make the vent of the size required; which, in most
cases, is generally 1/4th of their interior diameter. As it is very
often difficult, when the cases are rolled, to draw the roller out, a
hole must be made in its handle, and a pin, as a purchase, put in.
The machine for pinching cases consists of a treadle, which, when
pressed hard with the foot, will act upon a cord, and draw it tight.
The cord runs over a small pulley, and is fixed to an upright piece.
It is wound once round the case, between the former and end piece;
and when the cord is drawn, the case is brought together.
Cases are commonly rolled wet for wheels and fixed pieces; and when
they are required to contain a great length of charge, the method of
making these cases is thus: The paper must be cut as usual, except
the last, which ought not to have a slope. Having it ready, paste
each sheet on one side, and then fold down the first sheet as before
directed; but be careful that the paste does not touch the upper
side of the fold. If the roller be wetted, it will tear the paper
in drawing it out. In pasting the last sheet, observe not to wet
the last turn or two in that part where it is to be pinched; for if
that part be damp, the pinching cord will stick to it, and tear the
paper. Therefore, in choaking those cases, roll a bit of dry paper
once round the case, before the pinching cord is used. This paper
is to be taken off after the operation. The rolling board, and all
other methods, according to the former directions for the rolling and
pinching of cases, must be used for these, as well as other cases.
See _Encyclopedia Britannica_, vol. xv, p. 692.
Morel, in a practical work, (_Traité Practique des Feux d'Artifice_)
speaking of rocket cases, observes, that the rule is, to give to
their thickness, half the interior diameter, or half the diameter of
the roller. If the roller, for instance, were half an inch, the case
should be 1/4th of an inch in thickness. A rocket is divided into
three equal parts; two for the interior diameter, and one for the
thickness of the case.
As to the length of sky-rockets, it is regulated by the length of the
piercer, if they are pierced in the charging. One-third more than
this length is allowed for the _choak_, and the rest, of course, for
the composition. With respect to other cases, Morel remarks, that the
cases for turning pieces are usually six inches in length, and, for
fixed pieces, seven and eight inches. The cases of _Roman candles_,
are of the same thickness as those of rockets. In length they are, as
well as the _Mosaic candle_, fifteen inches. They are choaked and cut.
Those of _serpents_ are made with one or two cards, which are rolled
upon a former of wood, or metal, 1/4th of an inch in diameter, and
four inches in length. When made, the case measures three inches. Dry
rolling is considered sufficient for these cases.
The _fixed stars_ are made of common pasteboard, 3-1/2 inches long,
on a mandril, 1/2 an inch in diameter. They are pasted with ordinary
paste, but mixed with clay, and choaked, and bound as usual.
_Sec. VIII. Of Tourbillon Cases._
This kind of case is generally made 8 diameters long; but, if very
large, seven will be sufficient. From four ounces to two pounds, will
succeed perfectly, but, when larger, there is no certainty. They are
best rolled wet with paste, and the last sheet must have a straight
edge, so that the case may be all of a thickness. After rolling them
in the same manner as wheel cases, pinch them close at one end;
then, with a rammer, drive the ends down flat, and, afterwards, ram
in about one-third of a diameter of dried clay. The diameter of
the former for these cases, must be the same as for sky-rockets.
Tourbillons are to be rammed in moulds, without a nipple, or in a
mould without its foot. (_Ency. Brit._)
_Sec. IX. Of Balloon Cases, or Paper Shells._
First, prepare an oval former, turned out of smooth wood; then paste
a quantity of brown, or cartridge paper, and let it lie until the
paste is quite soaked through. This being done, rub the former with
soap or grease, to prevent the paper from sticking to it. Next,
lay the paper on in small slips, until you have made it one-third
the thickness of the shell intended. Having this done, set it to
dry; and when dry, cut it round the middle, and the two halves will
easily come off: but, observe, when you cut, to leave about one inch
not cut, which will make the halves join much better than if quite
separated. When you have some ready to join, place the halves even
together, and paste a slip of paper round the opening, to hold them
together, and let them dry. Then lay on paper, all over as before,
every where equally, excepting that end which goes downward in the
mortar, which may be a little thicker than the rest; for that part,
which receives the blow from the pounder in the chamber of the
mortar, consequently requires the greatest strength.
When the shell is perfectly dry, burn a vent at the top, with an
iron, large enough for the fuse. This method will answer for balloons
from 4 inches 2/5ths, to 8 inches in diameter; but, if they are
larger, or required to be thrown to a great height, let the first
shell be turned of elm, instead of being made of paper.
For balloons 4 inches 2/5ths, let the former be 3 inches 1/8th, in
diameter, and 5-1/2 inches long. For a balloon of 5-1/2 inches, the
diameter of the former must be 4 inches, and 8 inches long. For a
balloon of 8 inches, let the diameter of the form be 5 inches and
15/16ths, and 11 inches 7/8ths long. For a 10 inch balloon, let the
form be 7 inches 3/16ths, in diameter, and 14-1/2 inches long. The
thickness of a shell for a balloon of 4 inches 2/5ths, must be 1/2 an
inch. For a balloon of 5-1/2 inches, let the thickness of the paper
be 5/8ths, of an inch; for an 8 inch balloon, 7/8ths, of an inch; and
for a ten inch balloon, 1 inch and 1/8th of an inch.
Shells, that are designed for stars only, may be made quite round,
and the thinner they are at the opening, the better; for if they are
too strong, the stars are apt to break at the busting of the shell.
When making the shell, employ a pair of callipers, or a round gage;
so that you may not lay the paper thicker in one place than other,
and also that you may be able to know, when the shell is of a proper
thickness. Balloons must always be made to go easy into the mortars.
(See _Encycl. Brit. Art. Balloon cases_.)
_Sect. X. Of Cases for Illumination Port-fires._
These must be made very thin, of paper, and rolled on formers; from
2 to 3/8ths of an inch in diameter, and from 2 to 6 inches long:
they are pinched close at one end, and left open at the other. When
they are to be filled, put in but a little composition at a time, and
ram it lightly, so as not to break the case. Three or four rounds of
paper, with the last round pasted, will be sufficiently strong for
these cases. (_Ibid._)
_Sect. XI. Of Cases and Moulds for Common Port-fires._
Common port-fires, are intended purposely to fire the works, their
fire being very slow, and the heat of the flame so intense, that, if
applied to rockets, leaders, &c. it will fire them immediately. When
used, they are held in copper sockets, fixed in the end of a long
stick. These sockets are made like port-crayons, only with a screw
instead of a ring.
Port-fires, or _lances of service of the French_, may be made of any
length, but are seldom more than 21 inches long.
The interior diameter of port-fire moulds should be 10/16ths, of an
inch, and the diameter of the former half an inch. The cases must be
rolled wet with paste, and one end pinched or folded down. The moulds
should be made of brass, and to take in 2 pieces lengthwise: when the
case is in the two sides, they are held together by brass rings or
hoops, which are made to fit over the outside. The bore of the mould
must not be quite through, so that there will be no occasion for a
foot. The French make the cases of five thicknesses of paper, and
form the moulds upon rollers of 3/8ths of an inch in diameter.
Port fire, according to the full acceptation of the term _Porte-feu_
of the French, means a _porter_, or carrier of fire, and implies all
sorts of fusées or matches, by which fire is communicated.
In a treatise on _Military Fire-works_, as taught at Strasburg in
1764, an extract of which was translated and published by order
of the War Department in 1800, there are some observations on
port-fires, which, as the mode of making them according to these
directions appears to have been adopted, may be useful to notice in
this place.
"_Port-fires_ may be made in two ways. The first is made and beaten
in a mould; the other simply rolled on a ramrod, and filled lying on
the table.
"To make port-fires of the first kind, the mould must be made of dry
wood, such as pear-tree, nut or box wood. The height of the mould is
13.85 inches; its diameter at the bottom, 3.2 inches; its diameter
above, 2.13 inches; diameter of the hole or caliber, .62 inches;
height of the base, 2.13 inches; its diameter, 3.2 inches.
"The base of the mould has in the middle a nob, which the turner
leaves there, the diameter of which is equal to the whole of the
mould, and one inch high, including the circle, which should be
rounded like a hemisphere. There must be three rods, one of which,
of hard wood to roll the cartridge upon; the two others of iron to
ram down with. The one to roll upon, or the form, is to be of the
length of the mould, exclusive of the handle, which is 3.2 inches
longer. The diameter of this rod is .45 parts of an inch. The first,
or greater one to charge with, is the same length with that to roll
upon; the second is but half the length, and both are .44 parts of an
inch in diameter.
"To make good cartridges, you must have good paper, well sized, cut
according to the length of the rolling rod or form, which must be
rolled very tightly round the form, so that the vacancy left may be
exactly equal to the size of the mould, and that the paper should
exactly fill the space between the form and the mould. Then the form
is drawn out, after having tied it at the end with packthread. To
fill it, it must be replaced in the mould. A cupful of composition is
then put in, and five or six strokes given with the large ramrod. The
ramrod is then withdrawn, and a new charge is put in, which is beaten
like the first, until the cartridge is filled to the height of the
mould. It is then drawn out, and primed with priming powder.
"The port-fire is filled with ease, in using a tunnel placed at the
end of the cartouch, through which you pass the rod.
"_Composition of Port-fires of the first kind._
Saltpetre 4 lbs. 2 oz.
Sulphur 1 12
Priming powder 0 12
"After having mixed these materials well together with the hand, and
then with a rolling pin, you pass them through a hair sieve, and fill
your wooden bowls.
"_The second kind of Port-fires_, are made in rolling strips of paper
3 inches wide, and 1.278 inches long, on a form of hard wood, about
14 inches long, and .35 parts of an inch in diameter. When about
two-thirds of the paper is rolled, the remainder of it is to be
pasted over with paste made of flour and glue. You then finish it,
by passing your hand along the extremity of the pasted paper. Having
finished the number required, you place them in the sun, or near a
stove, and turn them from time to time, to prevent them from sticking
together, or bending.
"Cartridges being well dried, you must fill them with the following
composition. Fold the paper at one of the ends, and at the other,
pour in the composition, placing your cartridge against the
composition; and having placed it perpendicularly on the table, you
give it several strokes, to drive down the composition. Then you
take your iron rod, which is .53 parts of an inch longer than the
one which you use to roll with, and a little less in thickness at
the top. There should be a ring, that it may hang to the finger,
and move the more easily. Having laid your cartridges on the table,
you introduce the rod, and with it compress the composition. Having
withdrawn it, more is put in, it is pressed again, and so on until
entirely full. You will take care to press the last layer of the
composition more than the other, to prevent its falling out by moving.
"The port-fire cartridges being finished, they are laid by for use,
putting ten in a packet as before.
"_Composition of Port-fires of the second kind._
Saltpetre 6 ounces.
Sulphur 2 do.
Priming powder 3 do.
"These three articles being mixed, you will put them in a wooden
bowl, and moisten them with linseed oil, until you find the
composition (being pressed well) is sufficiently hard."
It may be sufficient to observe, that the present improved process of
making port-fires is preferable. (See _Port-fires_.)
_Sec. XII. Of Pasteboard, and its Uses._
The pasteboard, used in pyrotechny, is made of fine white paper, by
joining together five, and sometimes six, seven, and eight sheets of
paper. That which is generally employed, is made of five sheets, and
the other descriptions are employed for large cases. Sized paper is
preferable, having more firmness than the other.
Pasteboard is made in the following way: A paste of flour is first
prepared with hot water, and passed through a hair sieve, to separate
the lumps. A sheet of paper is stretched upon a table, and covered,
by means of a brush, with paste, and a sheet is then laid over it.
This is compressed, and another coat of paste applied; then another
sheet, then paste, and the number is added according to the thickness
required. After five or more sheets are thus pasted together, a dry
sheet is laid over, and the operation is repeated, till five more
are joined. Then a dry sheet is put on, and the pasting is renewed.
By this means, every five sheets are joined together, and the sheet,
thus formed, is kept apart from the rest, by the dry sheet. A pile of
pasteboard, consisting of some hundred sheets, may be made in this
manner at one time. They are then put into a press for the space of
five or six hours, by which they become firmly united, and all the
extraneous paste is pressed out. When a press cannot be had, they may
be put between boards, and heavy weights laid on. The pasteboard is
then hung up in the air to dry, and again submitted to the press, to
remove any inequalities, and to make it smooth.
When glazed paper is used for making pasteboard, we may employ,
alternately, a sheet of brown paper. It is better, however, to use
more of the glazed paper, than of the brown paper. Pasteboard of
three thicknesses will be sufficient for most purposes. It is this
kind, which is used for the heads of rockets.
Several kinds of paper, however, are used in fire-works. For small
preparations, common white paper is sufficient. For port-fire cases,
the common brown paper; for the joints, guarding places from fire,
and covering tubes of communication, any kind of gray paper; and for
covering marrons, the most indifferent kind may be used. Cartridge
paper, as known by that name, may be used for a variety of purposes.
Paper may be rendered incombustible, or nearly so, by soaking it
repeatedly in a strong solution of alum. In the _Literary Journal_
of 1785, of Petersburg, there is a discovery mentioned of a kind
of pasteboard, which neither fire can consume, nor water soften.
It appears that alumina, and its salt (alum) were used in this
preparation.
In the _Journal des Arts et Manufactures_, tom. ii, p. 205, is an
account of the manufacture of pasteboard at Malmedy; and in the
Transactions of the Society of Stockholm for 1785, is a description
of the process for making the Swedish stone paper, which resists
equally fire and water. Stone paper is manufactured in France,
(_Dictionnaire de l'Industrie_, article _Carton_), by taking two
parts of martial earth, (ochre, for instance), and mixing them with
one part of animal oil, and two parts of vegetable matter, previously
made into a pulp. The _British Repository of Arts_ contains several
specifications of patents for the preparation of the same paper.
Although paper may be rendered very difficult of combustion by the
process already mentioned, that of soaking it in a strong solution of
alum, yet to make a paper completely indestructible by fire, it must
be made of amianthus. The process for manufacturing paper with this
mineral, was announced in the _Gazette de France_ in 1778. Professor
Carbury received a medal for the invention.
Incombustible paper, for cartridges, ought to have the property,
not of inflaming, but of simply carbonizing, when exposed to heat.
M. Brugnatelli (_Bulletin des Neustin_) recommends the paper to be
prepared with silicated alkali, commonly called the liquor of flints.
Muriate of potassa, and supersulphate of alumina-and-potassa are both
used for a similar purpose.
Paper made according to Brugnatelli's process, is merely carbonized
by fire, and reduced to powder.
M. Hermbstaedt (_Bulletin des Découvertes_,) observes, that paper,
made with silicated liquor, attracts humidity, and proposes simply a
solution of green vitriol, which has not that property.
Paper may be stained, or coloured, in a variety of ways, as is the
case with the portable Chinese fire-works, that are brought to this
country. Thus, a red paper may be formed by dipping it in a decoction
of brazil wood and alum; yellow, by using fustic; a green, by a mixed
bath of blue and yellow dye, or a solution of copper, &c. Coloured
paper may be glazed with weak size, rubbing it afterwards with a
polished stone.
The Chinese are in possession of several processes, as well for
making, as for ornamenting paper. Their silver paper, which is
sometimes put on their fire-works, is variously figured. The art
is very simple. Two scruples of glue, and one scruple of alum, are
dissolved in a pint of water. This is evaporated, and put on the
paper, where they want it, and finally pulverized _silvery talc_ (a
magnesian stone) is sifted over it. It is then exposed to the sun,
and the extraneous talc is brushed off. The glue, it is obvious,
causes the talc to adhere.
The Abbé Raynal (_Histoire Philosophique des deux Indes_ t. iii,
p. 225) has some interesting facts respecting Chinese paper. Some
useful remarks on paper hangings, paper for decorations, tapestry
paper, &c. may be found in the _Journal de Paris_, 1785, the _Lycée
des Arts_ 1795, and the _Encyclopedie Method. Arts et Metiers_,
t. iv, p. 393. On the formation of paper vases, in imitation of
Japan vases, consult the _Dictionnaire de l'Industrie_, article
_vases_. The different patents, respecting paper, may be seen in
the British _Repertory of Arts_, and the manufacture of paper
generally, in Rees's _Cyclopedia_, and the _Artist's Manual_. The
American improvements are noticed in the latter. Beckman (_History
of Inventions_) has a variety of remarks on the same subject; and,
in his article on paper hangings, &c. vol. ii, p. 161, says, that
artists employed the silver-coloured glimmer (isinglass) for the
covering of paper, and that the nuns of Reichtinstein ornamented with
it, the images, which they made; as the nuns in France, and other
catholic countries, ornamented their _agni Dei_, by strewing over
them a shining kind of talc.
The quality of the paste, which is employed in making pasteboard,
ought to be attended to. The flour should be of rye, and well boiled,
after mixing it uniformly with cold water. Strong bookbinder's paste
has the addition of a fourth, fifth, or sixth of the weight of the
flour, of powdered alum. The _patent paste_ is prepared by extracting
starch from potatoes, in the usual manner, by means of cold water,
and mixing it with mashed potatoes, after they have been boiled, and
boiling the whole in water.
The Japanese cement, or rice-glue, may be advantageously used in many
cases. It is formed by mixing rice flour intimately with cold water,
and then boiling it very gently. It is beautifully white, and dries
almost transparent. We are told, that it is preferable, in every
respect, to the paste made with flour; and its strength is such, that
paper, pasted together with it, will sooner separate in their own
substance than at the joining.
The Chinese, to prevent accidents, and in order that they may fire
their works without injury, and particularly their cases which are
charged with brilliant fire, have a process, for preparing a paste of
a different kind. With the exception of the clay, the same substances
have been employed elsewhere for the like purpose. It consists of
one pound of rye flour, boiled in water; to which is added, a small
handful of common salt, the whole being _thickened_ with finely
pulverized white clay. The pasteboard, we are informed, which is made
with this paste, is not only very solid, but not so susceptible of
inflammation, as that prepared in the usual way.
A Chinese paste is announced in the _Bulletin de la Société
d'Encouragement_, 1815, which is very economical, and used with
success. It is made by mixing ten pounds of bullock's blood, with one
pound of quicklime, and occasionally flour.
_Sec. XIII. Of the Pulverization of Substances._
Various substances are employed either in grain, laminæ, filings, or
impalpable powder. When treating of nitre, sulphur, and charcoal, and
other bodies, we mentioned the processes for reducing them to powder.
It will be sufficient here to remark, that cannon powder, when it
is converted into fine powder, takes the name of meal-powder; the
conversion being effected, by beating it in a leather sack, already
described, by rolling it upon the mealing-table, or by the action
of a wooden pestle in a mortar. It is then passed through a fine
sieve. The sack is said to be a preferable mode, as nearly the whole
of it becomes pulverized. Saltpetre, sulphur, charcoal, antimony,
&c. may be reduced to powder in a mortar of cast-iron, marble, or
wood. The best method of pulverizing saltpetre is given under that
article, which consists in boiling it in a copper, and stirring it
continually at the end of the process. The best mode of pulverizing,
or bringing cast-iron to a state of fineness, is mentioned in the
article on _Iron_. Some of the metals, as iron, zinc, the alloy of
copper and zinc, (brass,) &c. are brought to a sufficient fineness
by the file. The filings, if so required, may be afterwards sifted.
Zinc, when in small pieces, may be pulverized, by means of a steel
mortar and pestle. It may be granulated, by suffering it to run, when
melted, through an iron cullender into water. For the pulverization
of camphor, see that article.
_Sec. XIV. Of Mixtures._
All compositions for fire-works, are generally made at first in
mortars, and the mixture is then finished by passing it through
a sieve; it being returned to the sieve, and again sifted. This
operation is sometimes repeated several times. Of all compositions,
that for sky-rockets requires to be most intimately blended.
To receive the sifted matter, leather or parchment is used; but, in
lieu of either, pasteboard, or several sheets of paper, cemented
or glued together will answer. It is obvious, that, in preparing
mixtures, of two, three, or four articles, they should not only be
very fine, but uniformly and intimately mixed.
Several receivers, made by stitching leather over a rim, in the
manner of a sieve, would be found very convenient; but wooden bowls,
and copper basins, are generally used.
Some ingredients must be passed through a lawn sieve, after having
been previously incorporated. A receiver, with a top, is the kind
of sieve to be preferred. The composition for wheels, and common
works, need not be so fine as for rockets. But in all fixed works,
from which the fire is to play regularly, the ingredients must be
very fine, and great care taken in mixing them together; and in those
works, into the composition of which, iron and steel enter, the hands
must neither touch them, nor moisture be suffered to come in contact.
In either case, they would be apt to rust.
PART III.
FIRE-WORKS IN GENERAL.
CHAPTER I.
OBSERVATIONS ON FIRE-WORKS.
In Europe, the invention of fire-works is of a recent date, and
ascribed to the Italians. In China, however, fire-works have been
known for centuries. Some recent exhibitions at Pekin prove, that
the Chinese have attained to a degree of perfection, not surpassed
by the artists of France, Italy, or England. The observations of Mr.
Barrow, (_Travels in China_), on this subject are worthy of notice.
"The fire-works, in some particulars," says he, "exceeded any thing
of the kind I had ever seen. In grandeur, magnificence, and variety,
they were, I own, inferior to the Chinese fire-works, we had seen at
Batavia, but infinitely superior in point of novelty, neatness, and
ingenuity of contrivance. One piece of machinery I greatly admired;
a chest five feet square, was hoisted up by a pulley, to the height
of fifty or sixty feet from the ground: the bottom was so constructed
as then, suddenly, to fall out, and make way for twenty or thirty
strings of lanterns, enclosed in a box, to descend from it, unfolding
themselves from one another by degrees, so as, at last, to form a
collection of full 500, each having a light of a beautifully coloured
flame, burning brightly within it. This devolution and development of
lanterns was several times repeated, and, at every time, exhibited a
difference of colour and figure. On each side, was a correspondence
of smaller boxes, which opened in like manner as the others, and let
down an immense net-work of fire, with divisions and compartments of
various forms and dimensions, round and square, hexagons, octagons,
&c. which shone like the brightest burnished copper, and flashed like
prismatic colours, with every impulse of the wind. The diversity
of colours, with which the Chinese have the secret of clothing
fire, seems one of the chief merits of their pyrotechny. The whole
concluded with a volcano, or general explosion and discharge of suns,
stars, squibs, crackers, rockets, and granadoes, which involved the
gardens for above an hour in a cloud of intolerable smoke."
Thevenot (_Travels in the Levant_) says, that during the bairam,
or carnival, which takes place with a great deal of ceremony, the
sultan causes fire-works to be played off all night; the sultan
and sultanas diverting themselves with these and other amusements.
Dr. Pococke (_Travels through Egypt_), says, that at Cairo, when
the Nile is high, besides aquatic excursions, concerts of music,
and other diversions, fire-works form a part of those pleasures
and recreations. In a _Description of the East Indies_, fire-works
are stated to be often exhibited at the marriage of the Banians or
Gentoos.
With respect to the arrangement and display of sundry pieces of
fire-works, either alone or combined, the effect depends, as well
upon the ingredients, which compose the several sorts of fire, as
on the taste displayed in their exhibition. It would be altogether
unnecessary to notice, at this time, the order of exhibition usually
adopted, reserving this subject until we have gone into the various
preparations, which constitute, as it is called, a _system of
fire-works_. In order, however, to become familiar with the manner of
arranging them, as well as with their composition and preparation,
whether designed for a general or a partial display, for the open air
or for rooms, we purpose to appropriate distinct chapters for their
consideration.
The variety of preparations, which become necessary where a full
exhibition is intended, the accuracy of the different mixtures, and
the adjustment of cases to wheels, whether vertical or horizontal,
and the arrangement of the leaders, or communicators of fire, from
one part to another of the work, with many other circumstances, in
relation to stars, rain, &c. all require, from the artist, particular
care and attention.
For the mere exhibition of one or two pieces, as a plain rocket,
rocket with serpents, or the like, and likewise for some exhibitions,
on water, called aquatic fire-works, in rooms or apartments, with
scented fire, or on the stage; the preparations are by no means
extensive.
It is, therefore, our design to present a view of the whole
subject in detail, and to speak of the different combinations
of arrangement, which are made according to fancy and taste, and
calculated, as we have remarked, either for small or extensive
exhibitions.
We have, in a preceding part of this work, made some observations
on certain preliminary operations; on the various sizes and charges
for cases; on the paper, necessary to be used, for different kinds
of cases; and, generally, on sundry manipulations, connected with
the making, filling, and preparation of sundry descriptions of
fire-works. It remains, therefore, in the course of this subject,
to give the several formulæ, with such observations as immediately
concern the subject; and for this purpose we will pursue the
following order:
Frazier is of opinion, that the arrangement of fire-works, which
have been exhibited with effect, may, on particular occasions, be
established as a guide. For this reason, Morel introduces an account
of the celebrated fire-works at Versailles and Paris, in 1739, which
we shall here notice.
_Exhibition of fire-works at the city house of Paris, on occasion of
the peace in 1739._
The theatre was a building, forty feet square, with a pyramid of
eighty feet in height, on which was placed a globe, containing
artificial fire, and accompanied with sixteen large vases of
different forms.
All the edifice was ornamented with a variety of decorations,
combined with figures and emblems of peace, and painted on marble.
After several guns were fired, as a signal, the exhibition commenced,
with the discharge of a large number of _honorary rockets_, fired
three and three at a time. Nearly five hundred _lances_, and
_saucissons_ garnished, lighted the four sides of the body of the
works. Thirty cases of artificial fire, furnished with _fusées_,
and double _marquises_, were placed upon the large terrace, with
1200 _pots à feu_ (fire-pots); and upon the ballustrade of the same
terrace, forty _jets_, twenty of which were _aigrettes_, and eight,
revolving suns, four in the middle, and four on the angles. Four
large fixed suns were placed above the four which revolved, and four
_pattes d'oies_, (_geese feet_,) were situated before the grand
pedestal of the pyramid, with _jets_, and _pots_ with _aigrette_.
At the foot of the pyramid, on the steps, were placed 1200
_fire-pots_, and upon the pedestal of the pyramid, twelve large pots
of _aigrette_, on the extremity of which, were arranged _aigrettes_
in groups, and three large luminous stars, formed of two hundred
fire lances. The four faces of the pyramid were lined with about
fifty other _jets_; after which there were cascades, or fountains
of fire. The first horizontal wheel was composed of, or furnished
with, six cases, and contained also two hundred and forty double
_marquises_. The second wheel contained two hundred and forty
_fire-pots_, and six cases, with upwards of three hundred _fusées_,
all in stars, twelve air balloons in the middle, but placed at the
bottom of the fire-work. To this was added, twelve artificial bombs,
fixed in mortars, and placed near the cannon, which pointed to the
works.
This outline of the brilliant exhibition of fire-works in 1739, will
give the reader some idea of the taste and magnificence of the work
at that period. We may here add, however, that the improvements,
which have since taken place, both in the composition of artificial
fire, and its arrangement, are such as to place the modern
exhibitions of this kind far above that we have just spoken of. But
the following account of the execution of fire-works, performed on
the _Pont Neuf_, in August of the same year, is more extensive, as
the exhibition appears to have been more grand.
The theatre, which represented the temple of Hymen, was an edifice
of the doric order. It was square. A gallery of five hundred feet in
length was supported by thirty-two columns, four feet in diameter,
and thirty-three feet in height. In the interior, were two solid
bodies, and also one or more stair cases. At the two sides of this
temple, along the parapets of the _Pont Neuf_, were thirty-six
pyramids, eighteen of which were forty feet high, and the others,
twenty-six feet. They were joined by what is called, in architecture,
a _corbil_, and carried vases on their summits.
The signal for the exhibition was given by the firing of cannon.
Immediately, were seen, rising into the air from each side of the
temple, three hundred rockets, fired twelve at a time. They were
discharged from the eight towers of the _Pont Neuf_, which face the
Tuileries, and were succeeded (upon the same towers,) by one hundred
and eighty _pots of aigrette_. The _Chinese trees_ were disposed in
such a manner, as to form a pyramid. A succession of _Chinese trees_
now appeared, immediately on the tablet of the cornice of the bridge;
then followed a great _fixed sun_, sixty feet in diameter, which
appeared in all its splendour, in the midst of surrounding objects.
Under this, was placed a large _illuminated cypher_, thirty feet
in height, which consisted of different colours, in imitation of
jewels. At the sides, between the pillars of the temple, were also
two other artificial _cyphers_, six feet high, and composed of _blue
fire_, which had a surprising effect. There were placed upon the two
walks of the bridge, on the right and left of the temple, beyond the
illuminated pyramids, two hundred cases of _fusées de partement_,
of five or six dozen each. These cases were fired, five at a time,
and succeeded the rockets. They began, on each side, from the first
near the temple, and in succession, as far as the extremities to
the right and left. There appeared then cascades of _red fire_,
issuing from the five arches of the bridge, which seemed to pierce
the illumination, and so vivid was the light, that the eye could
scarcely sustain it. The combat of the _dragons_ next ensued; and
the _water-fire_, or aquatic fire-works, covered almost the whole
surface of the river. Eight _boats_, containing works for the display
on water, were arranged in symmetrical order, with the _boats of
illumination_. There were also thirty-six _cascades_ or fountains
of fire, about thirty feet high, which appeared to rise out of the
water. This exhibition of the cascades, was preceded by a revolving
_water-sun_, and a discharge of _stars_ from one hundred and sixty
pots of _aigrettes_, which were placed at the lower part of the
terrace.
Four large boats, containing aquatic fire-works, were moored near the
arches of the bridge, and four others were disposed on the side next
to the Tuileries. The fire-works, which they contained, consisted
of a great number of large and small casks, charged with _gerbes_
and _pots_, which, when discharged, filled the air with _serpents_,
_stars_, &c. There was, also, a large number of _hand gerbes_, and
revolving _water-suns_.
When the exhibition of the cascades was finished, the grand
chandelier, composed of six thousand _fusées_, and resting on the top
of the temple, was lighted. Both extremities were set on fire at the
same time. This was followed by two smaller chandeliers, previously
placed on each side of the foot-way of the bridge, and containing
five hundred _fusées_ each.
The fire-works, exhibited at Versailles, in the same year, and on the
same occasion, were also magnificent. The account we have of them
is the following: There was a large building erected, representing
the temple of Hymen, nine hundred feet in length, and one hundred
and twenty in height, in the gardens of Versailles, in front of the
grand gallery. It was in the form of a portico, with re-enterings and
salients at the two extremities, which faced the two great basins;
and, in the centre, were illuminated works.
The forges of Vulcan, in the grottos, commenced with the sound of the
hammers of the Cyclops. The sparks, then produced, covered, in a few
instants, the two basins, provided for the purpose, with an apparent
sheet or volume of fire.
From the summit of a rock, came out a _jet_ of brilliant fire, more
than thirty feet in height, accompanied with four others of less
elevation, representing torrents of fire as from volcanoes. To this
succeeded a great _jet_ of water, forty-five feet in height, leading
with it, as it were, seventeen other _jets_, which surrounded the
rocks, and rushing forth with avidity, produced, in appearance, a
mixture of flame and water, which, in the end, consumed entirely the
two grottos.
After this, the fire-works, behind the decoration, were exhibited.
Two hundred and fifty _boxes_, and as many caissons, arranged on
both sides of the turf, which descended to the grass, were first
exhibited. This, however, was less brilliant than the fire from
the Cyclops. To this succeeded a brilliant fire, placed before the
illumination. This composition, elevating itself to a mean height,
pleased equally by its form, as by its brilliant whiteness. This
fire composed three distinct decorations, which succeeded as the one
replaced the other, following the same order. The spouting waters,
which decorated the gardens, together with the artificial fire,
appeared in the form of cascades and fountains. The first decoration,
at the head of the two great basins, exhibited two handsome cascades,
in the form of a white sheet, and surmounted with an _aigrette_
twenty-five feet in height. This was accompanied with two _pattes
d'oies_ (_geese feet_) of seven _jets_ each, and accompanied also
with fifty _jets_ playing from each of the sides, twenty feet in
height, and occupying the fore ground.
The second appeared under the form of the _pattes d'oies_, of eleven
jets each, of which four, at the head of the basins, were large,
and all projected a body of fire, fifty feet in height. They were
intermixed, however, with the pots of _aigrettes_, twenty feet in
height, which threw a crown, composed of stars, &c. to the height of
fifty feet, which produced in the atmosphere a lively and brilliant
light.
The third represented thirteen fountains of fire, twenty-five feet in
height, and thirty feet in diameter, with an _aigrette_ in each. In
these, there were six circular, and six spiral fountains. The largest
was placed between the two basins, with four others on the right and
left.
The fountains, which represented the combat of animals, had in each
of them two. The animals threw, at the same time, jets of water and
fire, and, between each of the fountains, large brilliant jets or
spouts. This part of the exhibition was finished, by throwing into
the air the _garnishing_ or furniture of the pots, which produced
crowns, &c. of great splendour.
To these three decorations, succeeded the exhibition of twelve
_Italian pots_, placed six in a row, and in the middle of two great
basins, which produced repeated discharges.
The whole was then closed by setting fire to two great chandeliers,
which were placed behind the grand decoration, and contained more
than three thousand _fusées_.
It appears from history, that when Henry II, entered Rheims, there
was a representation of several figures in fire; and in 1606, the
duke of Sully made an exhibition of fire-works at Fontainbleau;
and in 1612, Morel, commissary of artillery, prepared a splendid
exhibition of the same kind. It appears, also, that the art of
communicating fire from one piece of fire-work to another, as in the
combined piece of nine mutations, and the pyric-piece (which will be
noticed hereafter) was discovered by Ruggeri, artificer to the king,
at Boulogne, in France, in 1743.
It may not be improper, in concluding this article, to notice, in a
general manner, the exhibition of the works of fire by the ancients.
The fire-works of the ancients consisted, for the principal part, of
illuminations, and the use of some particular descriptions of fire.
They were, however, very imperfect. Since the invention of gunpowder,
its effects as well as its modifications, in this particular, became
known; and, so far as respects the various preparations of artificial
fire, gunpowder itself has produced a new era in pyrotechny, and the
various modifications, to which it is subject, have occasioned a
great variety of fire-works.
According to the authority we have on the subject, it appears, that
the ancients, in exhibiting their preparations of fire, set them off
by the hand, and directed them among the people, which produced great
eclat.
Another description of fire-work was designed expressly for the
theatre, part of which was exhibited in the form of man or beast.
Of their theatrical works, our accounts are imperfect. Their works,
generally, were formed of _lardons_, _stars_, and _fire-balls_, in
imitation of _grenades_, and _flying fusées_ or _rockets_. That they
neither had a system in arranging, nor regularity in exhibiting their
works, is evident from a variety of circumstances; for, although the
number of their pieces, such as they were, was great; yet, they
so crowded them upon each other, as that, when they were fired,
they frequently destroyed the persons in their vicinity. An author
of antiquity observes, that "he has seen a great many artificial
machines, but, to speak the truth, few which have succeeded; and it
is commonly after acclamations of joy, that the spectacle is finished
by the destruction of some, and the wounding of a great number."
This fact is not at all surprising; because their works were prepared
in wooden tubes, at least among the more modern, as paper cases
were not then known. These tubes, moreover, were not secured by any
covering, and were the more likely to burst, and hence accidents
were common. The moderns, however, have rejected altogether the use
of wood, in the formation of cases, and have availed themselves of
the use of paper, which can be made of any size or thickness. (See
_Pasteboard_.)
Notwithstanding wood is not employed by experienced fire-workers,
partly in consequence of the reasons just given, and partly because
paper furnishes a material in every way adapted to the purpose;
yet, within a few years past, reed has been used in Spain, which,
however, is secured by cloth and pack thread. Such substitutes,
nevertheless, besides being more or less dangerous, have nothing to
recommend them. It is a fact, that the Chinese, who undoubtedly excel
in the manufacture of fire-works, if we believe the authority of the
English embassy, use altogether paper cases; but in the _war-rocket_,
employed by the natives against the British at _Seringapatam_, which
did, according to the English account, great execution, their cases
were formed entirely of sheet-iron. In their smaller works, which are
prepared expressly for sale, paper cases are altogether made use of.