water, into a retort; apply the flame of a candle or lamp to the
bottom of the retort, until the contents boil. The phosphuretted
hydrogen gas will then rise, and may be collected in receivers. But
it, instead of receiving the gas into a jar, you let it simply ascend
into water, the bubbles of gas will then explode in succession, as
they reach the surface of the water, and a beautiful white smoke will
be formed, which rises slowly and majestically to the ceiling. If bits
of phosphorus are kept some hours in hydrogen gas, phosphorized
hydrogen gas is produced: and if bubbles of this gas are thrown up
into the receiver of an air-pump, previously filled with oxygen gas, a
brilliant bluish flame will immediately fill the jar.
_Singular Impression on the visual Nerves by a Luminous Object._
If, while sitting in a room, you look earnestly at the middle of a
window, a little while, when the day is bright, and then shut your
eyes, the figure of the window will still remain in your eye, and so
distinct that you may count the panes. A remarkable circumstance
attending this experiment is, that the impression of forms is better
retained than that of colours; for, after the eyes are shut, when you
first discern the image of the window, the panes appear dark, and the
cross-bars of the sashes, with the window frames and walls, appear
white and bright; but if you still add to the darkness of the eyes, by
covering them with your hand, the reverse instantly takes place--the
panes appear luminous, and the cross-bars dark; and by removing the
hand, they are again reversed.
_Curious Effects of Oil upon Water, and Water upon Oil._
Fasten a piece of pack-thread round a tumbler, with strings of the
same from each side, meeting above it in a knot at about a foot
distance from the top of the tumbler. Then putting in as much water as
will fill about one-third part of the tumbler, lift it up by the knot,
and swing it to and fro in the air; the water will keep its place as
steadily in the glass as if it were ice. But pour gently in upon the
water about as much oil, and then again swing it in the air as before,
the tranquillity before possessed by the water will be transferred to
the surface of the oil, and the water under it will be violently
agitated.
_Another curious Experiment with Oil and Water._
Drop a small quantity of oil into water agitated by the wind; it will
immediately spread itself with surprising swiftness upon the surface,
and the oil, though scarcely more than a tea-spoonful, will produce an
instant calm over a space several yards square. It should be done on
the windward side of the pond or river, and you will observe it extend
to the size of nearly half an acre, making it appear as smooth as a
looking-glass. One remarkable circumstance in this experiment is the
sudden, wide, and forcible spreading of a drop of oil on the surface
of the water; for if a drop of oil be put upon a highly polished
marble table, or a looking-glass, laid horizontally, the drop remains
in its place, spreading very little, but when dropped on water it
spreads instantly many feet round, becoming so thin as to produce the
prismatic colours for a considerable space, and beyond them so much
thinner as to be invisible, except in its effect in smoothing the
waves at a much greater distance. It seems as if a repulsion of its
particles took place as soon as it touched the water, and so strong as
to act on other bodies swimming on the surface, as straw, leaves,
chips, &c., forcing them to recede every way from the drop, as from a
centre, leaving a large clear space.
_Remarkable Effects on the visual Nerves, by looking through
differently-coloured Glasses._
After looking through green spectacles, the white paper of a book
will, on first taking them off, appear to have a blush of red; and
after looking through red glasses, a greenish cast. This seems to
intimate a relation between green and red, not yet explained.
_Weather Table._
--------------------+---------------------+------------------------
NEW AND FULL MOON. | SUMMER. | WINTER.
--------------------+---------------------+------------------------
If the new or full | |
moon enters into | |
the first or last | |
quarter of the | |
hour of 12 at noon | Very rainy | Snow and rain.
| |
If between the | |
hours of | |
(P.M.) 2 and 4 | Changeable | Fair and mild.
4 and 6 | Fair | Fair.
6 and 8 | { Fair, if wind | { Fair and frosty, if
| { at N.W. | { wind at N. or N.E.
| { Rainy, if wind | { Rain or snow, if S.
| { at S. or S.W. | { or S.W.
8 and 10 | Ditto | Ditto.
10 | Fair | Fair and frosty.
(A.M.) 2 | Ditto | { Hard frost, unless
| | { wind S.S.W.
2 and 4 | Cold, with frequent |
| showers |
4 and 6 | Rain | Ditto, ditto.
6 and 8 | Wind and Rain | Stormy weather.
8 and 10 | Changeable | { Cold and rain, if
| | { wind N.; snow if E.
10 and 12 | Frequent showers | Cold, with high wind.
--------------------+---------------------+-----------------------
A COMPLETE
SYSTEM OF PYROTECHNY;
OR THE
ART OF MAKING FIRE-WORKS.
In the art of making fire-works, great attention must be paid to the
well-mixing of the materials--without which all labour is thrown away;
to the purity of the articles; and to the proper quantities of each.
Sulphur, to be good, must be of a high colour, and crack and bounce
when held in the hand. For small fire-works, such as may be bought in
the flour will be found quite good enough, but for the larger kinds,
the lump brimstone ground is preferable.
_Benzoin_ is used in fire-works, more for its pleasant scent than any
material use for the purposes of fire. It may be procured at the
chemists, ready for use. The oil is also used in wet composition, for
stars, &c.
_Of Sulphur, or Brimstone._
Sulphur is by nature the food of fire, and one of the principal
ingredients in gunpowder, and in almost all compositions of
fire-works; therefore, great care ought to be taken of its being good,
and brought to the highest perfection. Now, to know when the sulphur
is good, you are to observe that it be of a high yellow; and if, when
held in one's hand, it crackles and bounces, it is a sign that it is
fresh and good: but as the method of reducing brimstone to a powder is
very troublesome, it is better to buy the flour ready made, which is
done in large quantities, and in great perfection; but when a great
quantity of fire-works is to be made, it is best to use the lump
brimstone ground, in the same manner as gunpowder.
_Of Saltpetre._
Saltpetre being the principal ingredient in fire-works, and a volatile
body by reason of its aqueous and aerial parts, is easily rarefied by
fire; but not so soon when foul and gross, as when purified from its
gross and earthy parts, which greatly retard its velocity; therefore,
when any quantity of fire-works is intended to be made, it would be
necessary first to examine the saltpetre; for if it be not well
cleansed from all impurities, and of a good sort, your works will not
have their proper effect.
_To pulverize Saltpetre._
Take a copper kettle, the bottom being spherical, and put into it
fourteen pounds of refined saltpetre, with two quarts or five pints of
clean water; then put the kettle on a slow fire, and when the
saltpetre is dissolved, if any impurities arise, skim them off, and
keep constantly stirring it with two large spatulas, till all the
water exhales; and when done enough, it will appear like white sand,
and as fine as flour; but if it should boil too fast, take the kettle
off the fire, and set it on some wet sand, which will prevent the
nitre from sticking to the kettle. When you have pulverized a quantity
of saltpetre, be careful to keep it in a dry place.
_To prepare Charcoal for Fire-works._
Charcoal is a preservative, by which the saltpetre and brimstone are
made into gunpowder, by preventing the sulphur from suffocating the
strong and windy exhalation of the nitre. There are several sorts of
wood made use of for this purpose; some prefer hazel, others willow,
and others alder. The method of burning the wood is this: cut it in
pieces of two or three feet long, then slit each piece in four parts;
scale off the bark and hard knots, and dry them in the sun, or in an
oven; then make in the earth a square hole, and line it with bricks,
in which lay the wood crossing one another, and set it on fire; when
thoroughly lighted, and in a flame, cover the whole with boards, and
fling earth over them close, to prevent the air from getting in, yet
so as not to fall among the charcoal; and when it has lain thus for
twenty-four hours, take out the coals and lay them in a dry place for
use. It is to be observed, that charcoal for fire-works must always be
soft and well burnt, which may be bought ready done.
_Of Gunpowder, &c._
Gunpowder being a principal ingredient in fire-works, it will not be
improper to give a short definition of its strange explosive force,
and cause of action, which, according to Dr. Shaw's opinion of the
chemical cause of the explosive force of gunpowder, is as
follows:--"Each grain of gunpowder consisting of a certain proportion
of sulphur, nitre, and coal, the coal presently taking fire, upon
contact of the smallest spark; at which time both the sulphur and the
nitre immediately melt, and by means of the coal interposed between
them, burst into flame; which spreading from grain to grain,
propagates the same effect almost instantaneously, whence the whole
mass of powder comes to be fired; and as nitre contains a large
proportion both of air and water, which are now violently rarefied by
the heat, a kind of fiery explosive blast is thus produced, wherein
the nitre seems, by its aqueous and aerial parts, to act as bellows to
the other inflammable bodies (sulphur and coal) to blow them into a
flame, and carry off their whole substance in smoke and vapour."
_How to meal Gunpowder, Brimstone, and Charcoal._
There have been many methods used to grind these ingredients to a
powder for fire-works, such as large mortars and pestles made of
ebony, and other hard woods; but none of these methods have proved so
effectual and speedy as the last invention, that of the mealing table.
This table is made of elm, with a rim round its edge four or five
inches high; and at the narrow end is a slider which runs in a groove
and forms part of the rim; so that when you have taken out of the
table as much powder as you conveniently can, with a copper shovel,
you may sweep all clean out at the slider. When you are going to meal
a quantity of powder, observe not to put too much on the table at
once; but when you have put in a good proportion, take a muller and
rub it therewith till all the grains are broken; sift it in a lawn
sieve, that has a receiver and top to it; and that which does not pass
through the sieve, return again to the table and grind it more, till
you have brought it all fine enough to go through the sieve. Brimstone
and charcoal are ground in the same manner as gunpowder, only the
muller must be made of ebony, for these ingredients being harder than
powder, would stick in the grain of the elm and be very difficult to
grind; and as the brimstone is apt to stick and clog to the table, it
would be best to keep one for that purpose only, by which means you
will always have your brimstone clean and well ground.
_Spur Fire._
This fire is the most beautiful of any composition yet known. As it
requires great trouble to bring it to perfection, particular care must
be paid to the following instructions. They are made generally in
cases about six inches long, but not driven very hard.
CHARGE. lb. oz. CHARGE. lb. oz.
Saltpetre 4 0 } { Saltpetre 1 0
Sulphur 2 0 } or { Sulphur 0 8
Lamp-black 1 8 } { Lamp-black 4 quarts.
This composition is very difficult to mix. The saltpetre and brimstone
must be first sifted together, and then put into a marble mortar, and
the lamp-black with them, which you work down by degrees with a wooden
pestle, till all the ingredients appear of one colour, which will be
something greyish, but very near black; then drive a little into a
case for trial, and fire it in a dark place; and if the sparks, which
are called stars or pinks, come out in clusters, and afterwards spread
well without any other sparks, it is a sign of its being good,
otherwise, not; for if any drossy sparks appear, and the stars not
full, it is then not mixed enough; but if the pinks are very small,
and soon break, it is a sign that you have rubbed it too much.
This mixture, when rubbed too much, will be too fierce, and hardly
show any stars; and, on the contrary, when not mixed enough, will be
too weak, and throw out an obscure smoke, and lumps of dross, without
any stars. The reason of this charge being called the spur fire is,
because the sparks it yields have a great resemblance to the rowel of
a spur, from whence it takes its name. As the beauty of this
composition cannot be seen at so great a distance as brilliant fire,
it has a better effect in a room than in the open air, and may be
fired in a chamber without any danger; it is of so innocent a nature,
that, although an improper phrase, it may be called a cold fire; and
so extraordinary is the fire produced from this composition, that, if
well made, the sparks will not burn a handkerchief when held in the
midst of them; you may hold them in your hand while burning, with as
much safety as a candle; and if you put your hand within a foot of the
case, you will feel the sparks fall like drops of rain.
_To make Touch Paper._
Dissolve in some spirits of wine or vinegar, a little saltpetre; then
take some purple or blue paper, wet it with the above liquor, and when
dry it will be fit for use. When you paste this paper on any of your
works, take care that the paste does not touch that part which is to
burn.
The method of using this paper is, by cutting it into slips, long
enough to go once round the mouth of the serpent, cracker, &c. When
you paste on these slips, leave a little, above the mouth of the case,
not pasted; then prime the case with meal-powder (see p. 165) and
twist the paper to a point.
_Of such Ingredients as show themselves in Sparks, when rammed into
choked Cases._
The set colours of fire produced by sparks are divided into four
sorts, viz., the black, white, grey, and red; the black charges are
composed of two ingredients, which are meal-powder and charcoal; the
white of three, viz., saltpetre, sulphur, and charcoal; the grey of
four, viz., meal-powder, saltpetre, brimstone, and charcoal; and the
red of three, viz., meal-powder, charcoal, and saw-dust.
There are, besides these four regular or set charges, two others
which are distinguished by the names of compound and brilliant
charges; the compound charge being made of many ingredients, such as
meal-powder, saltpetre, brimstone, charcoal, saw-dust, sea-coal,
antimony, glass-dust, brass-dust, steel-filings, cast-iron, tanners'
dust, &c., or any thing that will yield sparks; all which must be
managed with discretion. The brilliant fires are composed of
meal-powder, saltpetre, brimstone, and steel-dust; or with
meal-powder, and steel-filings only.
_Of the Method of mixing Compositions._
The performance of the principal part of fire-works depends much on
the compositions being well mixed; therefore, great care ought to be
taken in this part of the work, particularly in the composition for
sky-rockets. When you have four or five pounds of ingredients to mix,
which is a sufficient quantity at a time, (for a larger proportion
will not do so well,) first put the different ingredients together,
then work them about with your hands, till you think they are pretty
well incorporated: after which, put them into a lawn sieve with a
receiver and top to it; and if, after it is sifted, any should remain
that will not pass through the sieve, grind it again till fine enough;
and if it be twice sifted it will not be amiss; but the compositions
for wheels and common works are not so material, nor need be so fine.
But in all fixed works, from which the fire is to play regular, the
ingredients must be very fine, and great care taken in mixing them
well together: and observe, that, in all compositions wherein are
steel or iron filings, the hands must not touch; nor will any works
which have iron or steel in their charge, keep long in damp weather,
without being properly prepared, according to the following
directions:--
It may sometimes happen, that fire-works may be required to be kept a
long time, or sent abroad; neither of which could be done with
brilliant fires, if made with filings unprepared; for this reason,
that the saltpetre being of a damp nature, it causes the iron to rust,
the natural consequence of which is, that when the works are fired,
there will appear but very few brilliant sparks, but instead of them a
number of red and drossy sparks; and besides, the charge will be so
much weakened, that if this should happen to wheels, the fire will not
be strong enough to force them round; to prevent such accidents,
prepare your filings after the following manner:--Melt in a glazed
earthen pan some brimstone over a slow fire, and when melted, throw in
some filings, which keep stirring about till they are covered with
brimstone; this you must do while it is on the fire; then take it off,
and stir it very quick till cold, when you must roll it on a board
with a wooden roller, till you have broken it as fine as corn powder;
after which, sift from it as much of the brimstone as you can. There
is another method of preparing filings, so as to keep two or three
months in winter; this may be done by rubbing them between the
strongest sort of brown paper, which has been previously moistened
with linseed oil.
N.B. If the brimstone should take fire, you may put it out, by
covering the pan close at top. It is not of much consequence what
quantity of brimstone you use, provided there is enough to give each
grain of iron a coat; but as much as will cover the bottom of a pan of
about one foot diameter, will do for five or six pounds of filings.
Cast-iron for gerbes will be preserved by the above method.
_To make Crackers._
Cut some stout cartridge-paper into pieces three inches and a half
broad, and one foot long; one edge of each of these pieces fold down
lengthwise about three-quarters of an inch broad; then fold the double
edge down a quarter of an inch, and turn the single edge back half
over the double fold; open it, and lay all along the channel, which is
formed by the foldings of the paper, some meal-powder; then fold it
over and over till all the paper is doubled up, rubbing it down every
turn; this being done, bend it backwards and forwards, two inches and
a half or thereabouts, at a time, as often as the paper will allow;
hold all these folds flat and close, and with a small pinching cord,
give one turn round the middle of the cracker, and pinch it close;
bind it with packthread, as tight as you can; then in the place where
it was pinched, prime one end, and cap it with touch-paper. When these
crackers are fired, they will give a report at every turn of the
paper; if you would have a great number of bounces, you must cut the
paper longer, or join them after they are made; but if they are made
very long before they are pinched, you must have a piece of wood with
a groove in it, deep enough to let in half the cracker; this will hold
it straight while it is pinching.
_To make Squibs and Serpents._
First make the cases, of about six inches in length, by rolling slips
of stout cartridge-paper three times round a roller, and pasting the
last fold; tying it near the bottom as tight as possible, and making
it air-tight at the end, by sealing-wax. Then take of gunpowder half a
pound, charcoal one ounce, brimstone one ounce, and steel-filings half
an ounce, (or in like proportion,) grind them with a muller, or pound
them in a mortar. Your cases being dry and ready, first put a
thimble-full of your powder, and ram it hard down with a ruler; then
fill the case to the top with the aforesaid mixture, ramming it hard
down in the course of filling, two or three times; when this is done
point with touch-paper, which should be pasted on that part which
touches the case, otherwise it is liable to drop off.
_Sky-Rockets._
Rockets being of the fire-works most in use, we shall give them the
preference in description. As the performance of rockets depends much
upon their moulds, they should be made according to the following
proportions:--Taking the diameter of the orifice, its height should be
equal to six diameters and two-thirds: the choke, one diameter and
one-third of this model, will serve for every rocket from 4 oz. to 6
lb.--For instance:--suppose the diameter of a rocket of 1 lb. be 1-1/2
inch, then its length being 6 diameters and two-thirds, the length of
the case must be 10-1/3 inches, and the choke 2-1/4 inches. Your
rammer must have a collar of brass, to prevent the wood from
splitting.
_Method of rolling Rocket Cases._--The cases must be made of the
strongest cartridge-paper, and rolled dry. The case of a
middling-sized rocket will take up paper of four or five sheets thick;
having cut your papers to a proper size, and the last sheet with a
slope at one end, fold down one end, and lay your former on the double
edge, and when you have rolled on the paper within two or three turns,
lay the next sheet on that part which is loose, and roll it all on.
Then, in order to roll the case as hard as possible, place it on a
table, and with a smooth board roll it for some time forwards on the
table, till it becomes quite hard and firm. This must be done with
every sheet. You have next to choke the case; for which purpose draw
your former a little distance from the bottom, then, with a cord, once
round the case, pull it rather easy at first, and harder, till you
have closed the end. To make it easy, you may dip the ends of the
inner sheets in water before rolling, then bind it with small twine.
Having thus pinched and tied the case so as not to give way, put it
into the mould without its foot, and with a mallet drive the former
hard on the end-piece, which will force the neck close and smooth.
This 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 a long rammer, and the vent will be of a proper
size.
Having formed your cases, we will now proceed to the description of
the ingredients necessary for the rocket.
_Of mixing the Composition._--The performance of the principal part of
fire-works depends much on the compositions being well mixed;
therefore, great care must be taken in this part of the work,
particularly for the composition for sky-rockets. When you have four
or five pounds of ingredients to mix, which is a sufficient quantity
at a time, (for a large proportion will not do so well,) first put the
different ingredients together, then work them about with your hands,
till you think they are pretty well incorporated; after which, put
them into a lawn sieve with a receiver and top to it; and if, after it
is sifted, any remains that will not pass through the sieve, grind it
again till it is fine enough; and if it be twice sifted it will not be
amiss; but the compositions for wheels and common works are not so
material, nor need be so fine. But in all fixed works, from which the
fire is to play regular, the ingredients must be very fine, and great
care taken in mixing them well together; and observe, that in all
compositions wherein are iron filings, the hand must not touch them;
nor will any works which have iron or steel in their charge keep long
in damp weather.
_To drive or ram Rockets._--Rockets are filled hollow, otherwise they
would not ascend, and there is not a part that requires greater
attention than this stage of the process. One blow more or less with
the mallet will spoil the ascent.
The charge of rockets must always be driven above the piercer, and on
it must be rammed a thin head of clay; through the middle of which
bore a small hole to the composition, that when the charge is burnt to
the top, it may communicate its fire through the hole to the stars in
the head. To a rocket of four ounces, give to each ladle-full of
charge 16 strokes; to a rocket of 1 lb., 28; to a 2-pounder, 36; to a
4-pounder, 42; and to a 6-pounder, 56; but rockets of a larger sort
cannot be driven well by hand, but must be rammed with a machine made
in the same manner as those for driving piles.
The method of ramming wheel cases, or any other sort in which the
charge is driven solid, is the same as sky-rockets.