_Mordant_ A, as commonly made by the dyers, is composed of 8 parts of
aquafortis, 1 part of common salt or sal ammoniac, and 1 of granulated
tin. This preparation is very uncertain.
_Mordant_ B.--Pour into a glass globe with a long neck, 3 parts of pure
nitric acid at 30° B.; and 1 part of muriatic acid at 17°; shake the
globe gently, avoiding the corrosive vapours, and put a loose stopper in
its mouth. Throw into this nitro-muriatic acid, one-eighth of its weight
of pure tin, in small bits at a time. When the solution is complete, and
settled, decant it into bottles, and close them with ground stoppers. It
should be diluted only when about to be used.
_Mordant_ C, by Dambourney.--In two drams Fr. (144 grs.) of pure
muriatic acid, dissolve 18 grains of Malacca tin. This is reckoned a
good mordant for brightening or fixing the colour of peachwood.
_Mordant_ D, by Hellot.--Take 8 ounces of nitric acid, diluted with as
much water; dissolve in it half an ounce of sal ammoniac, and 2 drams of
nitre. In this acid solution dissolve one ounce of granulated tin of
Cornwall, observing not to put in a fresh piece till the preceding be
dissolved.
_Mordant_ E, by Scheffer.--Dissolve one part of tin in four of a
nitro-muriatic acid, prepared with nitric acid diluted with its own
weight of water, and one thirty-secondth of sal ammoniac.
_Mordant_ F, by Poërner.--Mix one pound of nitric acid with one pound of
water, and dissolve in it an ounce and a half of sal ammoniac. Stir it
well, and add, by very slow degrees, two ounces of tin turned into thin
ribbons upon the lathe.
_Mordant_ G, by Berthollet.--Dissolve in nitric acid of 30° B.,
one-eighth of its weight of sal ammoniac, then add by degrees one-eighth
of its weight of tin, and dilute the solution with one-fourth of its
weight of water.
_Mordant_ K, by Dambourney.--In one dram (72 grs.) of muriatic acid at
17°, one of nitric acid at 30°, and 18 grains of water, dissolve, slowly
and with some heat, 18 grains of fine Malacca tin.
_Mordant_ L, is the birch bark prescribed by Dambourney.--This bark,
dried and ground, is said to be a very valuable substance for fixing the
otherwise fugitive colours produced by woods, roots, archil, &c.
TIN-PLATE. The only alloy of iron interesting to the arts, is that with
tin, in the formation of _tin-plate_, or _white-iron_.
The sheet iron intended for this manufacture is refined with charcoal
instead of coke, subsequently rolled to various degrees of thinness, and
cut into rectangles of different sizes, by means of a shearing-machine
driven by a water-wheel, which will turn out 100 boxes a day, or four
times the number cut by hand labour. The first step towards tinning, is
to free the metallic surface from every particle of oxide or impurity,
for any such would inevitably prevent the iron from alloying with the
tin. The plates are next bent separately by hand into a saddle or Λ
shape, and ranged in a reverberatory oven, so that the flame may play
freely among them, and heat them to redness. They are then plunged into
a bath, composed of four pounds of muriatic acid diluted with three
gallons of water, for a few minutes, taken out and drained on the floor,
and once more exposed to ignition in a furnace, whereby they are
_scaled_, that is to say, cast their scales. The above bath will suffice
for scaling 1800 plates. When taken out, they are beat level and smooth
on a cast-iron block, after which they appear mottled blue and white, if
the _scaling_ has been thoroughly done. They are next passed through
_chilled_ rolls or cast-iron cylinders, rendered very hard by being cast
in thick iron moulds, as has been long practised by the Scotch founders
in casting bushes for cart-wheels. After this process of _cold rolling_,
the plates are immersed, for ten or twelve hours, in an acidulous lye,
made by fermenting bran-water, taking care to set them separately on
edge, and to turn them at least once, so that each may receive a due
share of the operation. From this lye-steep they are transferred into a
leaden trough, divided by partitions, and charged with dilute sulphuric
acid. Each compartment is called a _hole_ by the workmen, and is
calculated to receive about 225 plates, the number afterwards packed up
together in a _box_. In this liquid they are agitated about an hour,
till they become perfectly bright, and free from such black spots as
might stain their surface at the time of immersion. This process, called
pickling, is both delicate and disagreeable, requiring a good workman,
at high wages. The temperature of the two last steeps should be at least
90° or 100° F., which is kept up by stoves in the apartments. The plates
are finally scoured with hemp and sand in a body of water, and then put
aside for use in a vessel of pure water, under which they remain bright
and free from rust for many months, a very remarkable circumstance.
The _tinning_ follows these preparatory steps. A range of rectangular
cast-iron pots is set over a fire-flue in an apartment called the
_stow_, the workmen stationing themselves opposite to the narrow ends.
The first rectangle in the range is the tin-pot; the second is the
wash-pot, with a partition in it; the third is the grease-pot; the
fourth is the pan, grated at bottom; the fifth is the list-pot, and is
greatly narrower than any of the rest: they are all of the same length.
The prepared plates, dried by rubbing bran upon them, are first immersed
one by one in a pot filled with melted tallow alone, and are left there
for nearly an hour. They are thence removed, with the adhering grease,
into pot No. 1., filled with a melted mixture of block and grain tin,
covered with about four inches of tallow, slightly carbonized. This pot
is heated by a fire, playing under its bottom and round its sides, till
the metal becomes so hot as nearly to inflame the grease. Here about 340
plates are exposed, upright, to the action of the tin for an hour and a
half, or more, according to their thickness. They are next lifted out,
and placed upon an iron grating, to let the superfluous metal drain off;
but this is more completely removed in the next process, called
_washing_.
Into the wash-pot, No. 2., filled with melted _grain_ tin, the workman
puts the above plates, where the heat detaches the ribs, and drops.
There is a longitudinal partition in it, for keeping the drop of tin
that rises in washing from entering the vessel where the last dip is
given. Indeed, the metal in the wash-pot, after having acted on 60 or 70
boxes, becomes so foul, that the weight of a block (300 cwt.) of it, is
transferred into the tin-pot, No. 1., and replaced by a fresh block of
grain tin. The plates being lifted out of the wash-pot, with tongs held
in the left hand of the workman, are scrubbed on each side with a
peculiar hempen brush, held in his right hand, then dipped for a moment
in the hot tin, and forthwith immersed in the adjoining grease-pot, No.
3. This requires manual dexterity; and though only three-pence be paid
for brushing and tin-washing 225 plates, yet a good workman can earn six
shillings and three-pence in twelve hours, by putting 5625 plates
through his hands. The final tin-dip is useful to remove the marks of
the brush, and to make the surface uniformly bright. To regulate the
temperature of the tallow-pot, and time during which the plates are left
in it, requires great skill and circumspection on the part of the
workman. If kept in it too long, they would be deprived to a certain
extent of their silvery lustre; and if too short, streaks of tin would
disfigure their surface. As a thick plate retains more heat after being
lifted out of the washing-pot, it requires a proportionally cooler
grease-pot. This pot has pins fixed within it, to keep the plates
asunder; and whenever the workman has transferred five plates to it, a
boy lifts the first out into the cold adjoining pan, No. 4.; as soon as
the workman transfers a sixth plate, the boy removes the second; and so
on. The manufacture is completed by removing the wire of tin left on the
under edge of the plates, in consequence of their vertical position in
the preceding operations. This is the business of the _list-boy_, who
seizes the plates when they are cool enough to handle, and puts the
lower edge of each, one by one, into the list-pot, No. 5., which
contains a very little melted tin, not exceeding a quarter of an inch in
depth. When he observes the wire-edge to be melted, he takes out the
plate, and, striking it smartly with a thin stick, detaches the
superfluous metal, which leaves merely a faint stripe where it lay. This
mark may be perceived on every tin-plate in the market.
The plates are finally prepared for packing up in their boxes, by being
well cleansed from the tallow, by friction with bran.
Mr. Thomas Morgan obtained a patent, in September, 1829, for clearing
the sheet-iron plates with dilute sulphuric acid in a _hole_, instead of
_scaling_ them in the usual way, previous to their being cold rolled,
annealed, and tinned; whereby, he says, a better article is produced at
a cheaper rate.
_Crystallized tin-plate_, see MOIRÉE METALLIQUE. It would seem that the
acid merely lays bare the crystalline structure really present on every
sheet, but masked by a film of redundant tin. Though this showy article
has become of late years vulgarized by its cheapness, it is still
interesting in the eyes of the practical chemist. The English tin-plates
marked F, answer well for producing the _Moirée_, by the following
process. Place the tin-plate, slightly heated, over a tub of water, and
rub its surface with a sponge dipped in a liquor composed of four parts
of aquafortis, and two of distilled water, holding one part of common
salt or sal ammoniac in solution. Whenever the crystalline spangles seem
to be thoroughly brought out, the plate must be immersed in water,
washed either with a feather or a little cotton (taking care not to rub
off the film of tin that forms the feathering), forthwith dried with a
low heat, and coated with a lacquer varnish, otherwise it loses its
lustre in the air. If the whole surface is not plunged at once in cold
water, but if it be partially cooled by sprinkling water on it, the
crystallization will be finely variegated with large and small figures.
Similar results will be obtained by blowing cold air through a pipe on
the tinned surface, while it is just passing from the fused to the solid
state; or a variety of delineations may be traced, by playing over the
surface of the plate with the pointed flame of a blowpipe.
The following TABLE shows the several sizes of tin-plates, the marks by
which they are distinguished, and their current wholesale prices in
London:--
+------------------+---------+----+------+--------+----------------+
|Names. |Sizes. |No. |Weight|Marks |Prices per |
| | |in a|of |on the |box, in |
| | |box.|each |boxes. +--------+-------+
| | | |box. | | 1823. | 1838. |
+------------------+---------+----+------+--------+--------+-------+
| |_Inches._| |c q l| |_s._ |_s. d._|
|Common, No. 1. |13-3/4 by| | | | | |
| |10 | 225|1 0 0|CI. |47 | 35 |
| Ditto 2. |13-1/4 --| | | | | |
| | 9-1/4 | |0 3 21|CII. |45 | 33 6 |
| Ditto 3. |12-3/4 --| | | | | |
| | 9-1/2 | |0 3 16|CIII. |43 | 32 9 |
|Cross, No. 1. |13-3/4 --| | | | | |
| |10 | |1 1 0|XI. |53 | 40 2 |
|Two crosses, 1. | | |1 1 21|XXI. |58 | 43 2 |
|Three crosses, 1. | | |1 2 14|XXX. I. |63 | 47 |
|Four crosses, 1. | | |1 3 7|XXXX. I.| | |
|Common doubles |16-3/4 --| | | | | |
| |12-1/2 | 100|0 3 21|CD. |64-6} | 48 6 |
|Cross doubles | | |1 0 14|XD. |73-6}[A]| 56 |
|Two cross do. | | |1 1 7|XXD. |81 } | 60 6 |
|Three cross do. | | |1 2 0|XXXD. |88-6} | 65 |
|Four cross do. | | |1 2 21|XXXXD. | | |
|Com. small doubles| 5 -- 11| 200|1 2 0|CSD. |69 | 51 6 |
|Cross do. do. | | |1 2 21|XSD. |75 | 56 0 |
|Two cross do. | | |1 3 14|XXSD. |80 | 59 6 |
|Three do. do. | | |2 0 7|XXXSD. | | |
|Four do. do. | | |2 1 0|XXXXSD. | | |
|Waster’s com. | 3-3/4 --| | | | | |
|No. 1. |10 | 225|1 0 0|WCI. |44 | 32 9 |
|Ditto cross, 1.| ditto | |1 1 0|WXI. |50 | 47 3 |
+------------------+---------+----+------+--------+--------+-------+
c = _cwt._
q = _qrs._
l = _lbs._
[A] = 150 sheets in each.
These are the cash prices of one wholesale warehouse in Thames-street;
an immediately adjoining warehouse charges fully 1_s._ more upon the
standard CI, and proportionally upon the others.
TITANIUM, is a rare metal, discovered by Klaproth, in menachanite, in
1794. It has been detected since in the form of small cubes of a
copper-red colour, in some of the blast furnaces in Yorkshire. According
to Hassenfratz, its presence in small quantity does not impair the
malleability of iron. It is very brittle, so hard as to scratch steel,
and very light, having a specific gravity of only 5·3. It will not melt
in the heat of any furnace, nor dissolve, when crystallized, even in
nitro-muriatic acid; but only when in fine powder. By calcination with
nitre, it becomes oxygenated, and forms titanate of potassa. Traces of
this metal may be detected in many irons, both wrought and cast. The
principal ores of titanium are _sphene_, common and foliated, _rutile_,
_iserine_, _menachanite_, and _octahedrite_ or _pyramidal titanium ore_.
None of them has been hitherto applied to any use.
TOBACCO. It is said that the name tobacco was given by the Spaniards to
the plant, because it was first observed by them at Tabasco, or Tabaco,
a province of Yucatan in Mexico. In 1560, Nicot, the French ambassador
to Portugal, having received some tobacco from a Flemish merchant,
showed it, on his arrival in Lisbon, to the grand prior, and, on his
return into France, to Catherine of Medicis, whence it has been called
Nicotiana by the botanists. Admiral Sir Francis Drake having, on his way
home from the Spanish Main, in 1586, touched at Virginia, and brought
away some forlorn colonists, is reported to have first imported tobacco
into England. But, according to Lobel, this plant was cultivated in
Britain before the year 1570; and was consumed by smoking in pipes by
Sir Walter Raleigh, and companions, so early as the year 1584.
The plants are hung up to dry during four or five weeks; taken down out
of the sheds in damp weather, for in dry they would be apt to crumble
into pieces; stratified in heaps, covered up, and left to sweat for a
week or two, according to their quality and the state of the season;
during which time they must be examined frequently, opened up, and
turned over, lest they become too hot, take fire, or run into
putrefactive fermentation. This process needs to be conducted by skilful
and attentive operatives. An experienced negro can form a sufficiently
accurate judgment of the temperature, by thrusting his hand down into
the heap.
The tobacco thus prepared, or often without fermentation, is sent into
the market; but, before being sold, it must undergo the inspection of
officers, appointed by the state with very liberal salaries, who
determine its quality, and brand an appropriate stamp upon its casks, if
it be sound; but if it be bad, it is burned.
Our respectable tobacconists are very careful to separate all the
damaged leaves, before they proceed to their preparation, which they do
by spreading them in a heap upon a stone pavement, watering each layer
in succession, with a solution of sea salt, of spec. grav. 1·107, called
_sauce_, till a ton or more be laid; and leaving their principles to
react on each other for three or four days, according to the
temperature, and the nature of the tobacco. It is highly probable that
ammonia is the volatilizing agent of many odours, and especially of
those of tobacco and musk. If a fresh green leaf of tobacco be crushed
between the fingers, it emits merely the herbaceous smell common to many
plants; but if it be triturated in a mortar, along with a little
quicklime or caustic potash, it will immediately exhale the peculiar
odour of snuff. Now analysis shows the presence of muriate of ammonia in
this plant, and fermentation serves further to generate free ammonia in
it; whence, by means of this process, and lime, the odoriferous vehicle
is abundantly developed. If, on the other hand, the excess of alkaline
matter in the tobacco of the shops be saturated by a mild dry acid, as
the tartaric, its peculiar aroma will entirely disappear.
Tobacco contains a great quantity of an azotized principle, which by
fermentation produces abundance of ammonia; the first portions of which
saturate the acid juices of the plant, and the rest serve to volatilize
its odorous principles. The salt water is useful chiefly in moderating
the fermentation, and preventing it from passing into the putrefactive
stage; just as salt is sometimes added to saccharine worts in tropical
countries, to temper the fermentative action. The sea salt, or
concentrated sea water, which contains some muriate of lime, tends to
keep the tobacco moist, and is therefore preferable to pure chloride of
sodium for this purpose. Some tobacconists mix molasses with the salt
_sauce_, and ascribe to this addition the violet colour of the _macouba_
snuff of Martinique; and others add a solution of extract of liquorice.
The following prescription is that used by a skilful manufacturer:--In a
solution of the liquorice juice, a few figs are to be boiled for a
couple of hours; to the decoction, while hot, a few bruised anise-seeds
are to be added, and when cold, common salt to saturation. A little
silent spirit of wine being poured in, the mixture is to be equably, but
sparingly, sprinkled with the rose of a watering-pot, over the leaves of
the tobacco, as they are successively stratified upon the preparation
floor.
The fermented leaves, being next stripped of their middle ribs by the
hands of children, are sorted anew, and the large ones are set apart for
making cigars. Most of the tobaccos on sale in our shops are mixtures of
different growths: one kind of smoking tobacco, for example, consists of
70 parts of Maryland, and 30 of meagre Virginia; and one kind of snuff
consists of 80 parts of Virginia, and 30 parts of either Humesfort or
Warwick. The Maryland is a very light tobacco, in thin yellow leaves;
that of Virginia is in large brown leaves, unctuous or somewhat gluey on
the surface, having a smell somewhat like the figs of Malaga; that of
Havannah is in brownish, light leaves, of an agreeable and rather spicy
smell; it forms the best cigars. The Carolina tobacco is less unctuous
than the Virginian; but in the United States it ranks next to the
Maryland.
The shag tobacco is dried to the proper point upon sheets of copper.
Tobacco is cut into what is called shag tobacco by knife-edged chopping
stamps, a machine somewhat similar to that represented under METALLURGY,
_fig._ 670. For grinding the tobacco leaves into snuff, conical mortars
are employed, somewhat like that used by the Hindoos for grinding
sugar-canes, _fig._ 1080.; but the sides of the snuff-mill have sharp
ridges from the top to near the bottom.
Mr. L. W. Wright obtained a patent in August, 1827, for a
tobacco-cutting machine, which bears a close resemblance to the
well-known machines with revolving knives, for cutting straw into chaff.
The tobacco, after being squeezed into cakes, is placed upon a smooth
bed within a horizontal trough, and pressed by a follower and screws to
keep it compact. These cakes are progressively advanced upon the bed, or
fed in, to meet the revolving blades. The speed of the feeding-screw
determines the degree of fineness of the sections or particles into
which the tobacco is cut.
I was employed some years ago by the Excise, to analyze a quantity of
snuff, seized on suspicion of having been adulterated by the
manufacturer. I found it to be largely drugged with pearl-ashes, and to
be thereby rendered very pungent, and absorbent of moisture; an
economical method of rendering an effete article at the same time active
and aqueous.
According to the recent analysis of Possett and Reimann, 10,000 parts of
tobacco-leaves contain--6 of the peculiar chemical principle _nicotine_;
1 of _nicotianine_; 287 of slightly bitter extractive; 174 of gum, mixed
with a little malic acid; 26·7 of a green resin; 26 of vegetable
albumen; 104·8 of a substance analogous to gluten; 51 of malic acid; 12
of malate of ammonia; 4·8 of sulphate of potassa; 6·3 of chloride of
potassium; 9·5 of potassa, which had been combined with malic and nitric
acids; 16·6 of phosphate of lime; 24·2 of lime, which had been combined
with malic acid; 8·8 of silica; 496·9 of fibrous or ligneous matter;
traces of starch; and 88·28 of water.
_Nicotine_ is a transparent colourless liquid, of an alkaline nature. It
may be distilled in a retort plunged into a bath heated to 290°
Fahrenheit. It has a pricking, burning taste, which is very durable; and
a pungent disagreeable smell. It burns by means of a wick, with the
diffusion of a vivid light, and much smoke. It may be mixed with water
in all proportions. It is soluble also in acetic acid, oil of almonds,
alcohol, and ether, but not in oil of turpentine. It acts upon the
animal economy with extreme violence; and in the dose of one drop it
kills a dog. It forms salts with the acids. About one part of it may be
obtained by very skilful treatment from one thousand of good tobacco.
Tobacco imported into the United Kingdom, viz.--unmanufactured, in 1836,
52,232,907 lbs.; in 1837, 27,070,448 lbs.;--manufactured, and snuff, in
1836, 182,248 lbs.; in 1837, 642,287 lbs. Retained for home consumption,
unmanufactured, in 1836, 22,309,021 lbs.; in 1837, 22,504,343
lbs.:--manufactured, and snuff, in 1836, 159,226 lbs.; in 1837, 145,045
lbs. Duty received,--on unmanufactured tobacco, in 1836, _£_3,344,703;
in 1837, _£_3,375,125; on manufactured tobacco, and snuff, in 1836,
£71,560; in 1837, _£_65,220.
TOBACCO-PIPES. The practice of smoking tobacco has become so general in
many nations as to render the manufacture of tobacco-pipes a
considerable branch of industry. Some seek in the inhalation of
tobacco-smoke a pleasurable narcotism; others imagine it to be
beneficial to their health; but, in general, smoking is merely a dreamy
resource against ennui, which ere long becomes an indispensable
stimulus. The filthiness of this habit, the offensive odour which
persons under its influence emit from their mouths and clothes, the
stupor it too often occasions, as well as the sallow complexion, black
or carious teeth, and impaired digestion, all prove the great
consumption of tobacco to be akin in evil influence upon mankind to the
use of ardent spirits.
Tobacco-pipes are made of a fine-grained plastic white clay, to which
they have given the name. It is worked with water into a thin paste,
which is allowed to settle in pits, or it may be passed through a sieve,
to separate the siliceous or other stony impurities; the water is
afterwards evaporated till the clay becomes of a doughy consistence,
when it must be well kneaded to make it uniform. Pipe-clay is found
chiefly in the isle of Purbeck and Dorsetshire. It is distinguished by
its perfectly white colour, and its great adhesion to the tongue after
it is baked; owing to the large proportion of alumina which it contains.
A child fashions a ball of clay from the heap, rolls it out into a
slender cylinder upon a plank, with the palms of his hands, in order to
form the stem of the pipe. He sticks a small lump to the end of the
cylinder for forming the bowl; which having done, he lays the pieces
aside for a day or two, to get more consistence. In proportion as he
makes these rough figures, he arranges them by dozens on a board, and
hands them to the pipemaker.
The pipe is finished by means of a folding brass or iron mould,
channelled inside of the shape of the stem and the bowl, and capable of
being opened at the two ends. It is formed of two pieces, each hollowed
out like a half-pipe, cut as it were lengthwise; and these two jaws,
when brought together, constitute the exact space for making one pipe.
There are small pins in one side of the mould, corresponding to holes in
the other, which serve as guides for applying the two together with
precision.
The workman takes a long iron wire, with its end oiled, and pushes it
through the soft clay in the direction of the stem, to form the bore,
and he directs the wire by feeling with his left hand the progress of
its point. He lays the pipe in the groove of one of the jaws of the
mould, with the wire sticking in it; applies the other jaw, brings them
smartly together, and unites them by a clamp or vice, which produces the
external form. A lever is now brought down, which presses an oiled
stopper into the bowl of the pipe, while it is in the mould, forcing it
sufficiently down to form the cavity; the wire being meanwhile thrust
backwards and forwards so as to pierce the tube completely through. The
wire must become visible at the bottom of the bowl, otherwise the pipe
will be imperfect. The wire is now withdrawn, the jaws of the mould
opened, the pipe taken out, and the redundant clay removed with a knife.
After drying for a day or two, the pipes are scraped, polished with a
piece of hard wood, and the stems being bent into the desired form, they
are carried to the baking kiln, which is capable of firing fifty gross
in from 8 to 12 hours. A workman and a child can easily make five gross
of pipes in a day.
No tobacco-pipes are so highly prized as those made in Natolia, in
Turkey, out of meerschaum, a somewhat plastic magnesian stone, of a soft
greasy feel, which is formed into pipes after having been softened with
water. It becomes white and hard in the kiln.
[Illustration: 1155 1156]
A tobacco-pipe kiln should diffuse an equal heat to every part of its
interior, while it excludes the smoke of the fire. The crucible, or
large sagger, A, A, _figs._ 1155. and 1156., is a cylinder, covered in
with a dome. It is placed over the fireplace B, and enclosed within a
furnace of ordinary brickwork D, D, lined with fire-bricks E, E. Between
this lining and the cylinder, a space of about 4 inches all round is
left for the circulation of the flame. There are 12 supports or ribs
between the cylinder and the furnace lining, which form so many flues,
indicated by the dotted lines _x_, in _fig._ 1156. (the dotted circle
representing the cylinder). These ribs are perforated with occasional
apertures, as shown in _fig._ 1155., for the purpose of connecting the
adjoining flues; but the main bearing of the hollow cylinder is given by
five piers, _b_, _b_, _c_, formed of bricks projecting over and beyond
each other. One of these piers _c_, is placed at the back of the
fireplace, and the other four at the sides _b_, _b_. These project
nearly into the centre, in order to support and strengthen the bottom;
while the flues pass up between them, unite at the top of the cylinder
in the dome L, and discharge the smoke by the chimney N.
The lining F, E, E, of the chimney is open on one side to form the door,
by which the cylinder is charged and discharged. The opening is
permanently closed as high as _k_, _fig._ 1155., by an iron plate
plastered over with fire-clay; above this it is left open, and shut
merely with temporary brickwork while the furnace is going. When this is
removed, the furnace can be filled or emptied through the opening, the
cylindric crucible having a correspondent aperture in its side, which is
closed in the following ingenious way, while the furnace is in action.
The workman first spreads a layer of clay round the edge of the opening,
he then sticks the stems of broken pipes across from one side to the
other, and plasters up the interstices with clay, exactly like the
lath-and-plaster work of a ceiling. The whole of the cylinder, indeed,
is constructed in this manner, the bottom being composed of a great many
fragments of pipe stems, radiating to the centre; these are coated at
the circumference with a layer of clay. A number of bowls of broken
pipes are inserted in the clay; in these other fragments are placed
upright to form the sides of the cylinder. The ribs round the outside,
which form the flues, are made in the same way, as well as the dome L;
by which means the cylindric case may be made very strong, and yet so
thin as to require little clay in the building, a moderate fire to heat
it, while it is not apt to split asunder. The pipes are arranged within,
as shown in the figure, with their bowls resting against the
circumference and their ends supported on circular pieces of clay _r_,
which are set up in the centre for that purpose. Six small ribs are made
to project inwards all round the crucible, at the proper heights, to
support the different ranges of pipes, without having so many resting on
each other as to endanger their being crushed by the weight. By this
mode of distribution, the furnace may contain 50 gross, or 7200 pipes,
all baked within 8 or 9 hours; the fire being gradually raised, or
damped if occasion be, by a plate partially slid over the chimney top.
TODDY, _Sura_, _Mee-ra_, sweet juice.--The proprietors of coco-nut
plantations in the peninsula of India, and in the Island of Ceylon,
instead of collecting a crop of nuts, frequently reap the produce of the
trees by extracting sweet juice from the flower-stalk. When the
flowering branch is half shot, the toddy-drawers bind the stock round
with a young coco-nut leaf in several places, and beat the spadix with a
short baton of ebony. This beating is repeated daily for ten or twelve
days, and about the end of that period a portion of the flower-stalk is
cut off. The stump then begins to bleed, and an earthen vessel (chatty)
or a calabash is suspended under it, to receive the juice, which is by
the Europeans called _toddy_.
A thin slice is taken from the stump daily, and the toddy is removed
twice a day. A coco-nut frequently pushes out a new _spadix_ once a
month; and after each spadix begins to bleed, it continues to produce
freely for a month, by which time another is ready to supply its place.
The old spadix continues to give a little juice for another month, after
which it withers; so that there are sometimes two pots attached to a
tree at one time, but never more. Each of these spadices, if allowed to
grow, would produce a bunch of nuts from two to twenty. Trees in a good
soil produce twelve bunches in the year; but when less favourably
situated, they often do not give more than six bunches. The quantity of
six English pints of toddy is sometimes yielded by a tree daily.
Toddy is much in demand as a beverage in the neighbourhood of villages,
especially where European troops are stationed. When it is drunk before
sunrise, it is a cool, delicious, and particularly wholesome beverage;
but by eight or nine o’clock fermentation has made some progress, and it
is then highly intoxicating.[68]
[68] Contributions to the History of the Coco-nut Tree. By Henry
Marshall, Esq., Deputy Inspector of Hospitals.
TOLU, is a brownish-red balsam, extracted from the stem of the
_Myroxilon toluiferum_, a tree which grows in South America. It is
composed of resin, oil, and benzoic acid. Having an agreeable odour, it
is sometimes used in perfumery. It has a place in the Materia Medica,
but for what good reason I know not.
TOMBAC, is a white alloy of copper.
TONKA BEAN, the fruit of the _Dipterix odorata_, affords a concrete
crystalline volatile oil (_stearoptène_), called _coumarine_ by the
French. It is extracted by digestion with alcohol, which dissolves the
stearoptène, and leaves a fat oil. It has an agreeable smell, and a warm
taste. It is fusible at 122° Fahrenheit, and volatile at higher heats.
TOPAZ. See LAPIDARY.
TORTOISE-SHELL, or rather scales, a horny substance, that covers the
hard strong covering of a bony contexture, which encloses the _Testudo
imbricata_, Linn. The lamellæ or plates of this tortoise are 13 in
number, and may be readily separated from the bony part by placing fire
beneath the shell, whereby they start asunder. They vary in thickness
from one-eighth to one-quarter of an inch, according to the age and size
of the animal, and weigh from 5 to 25 pounds. The larger the animal, the
better is the shell. This substance may be softened by the heat of
boiling water; and if compressed in this state by screws in iron or
brass moulds, it may be bent into any shape. The moulds being then
plunged in cold water, the shell becomes fixed in the form imparted by
the mould. If the turnings or filings of tortoise-shell be subjected
skilfully to gradually increased compression between moulds immersed in
boiling water, compact objects of any desired ornamental figure or
device may be produced. The soldering of two pieces of scale is easily
effected, by placing their edges together, after they are nicely filed
to one bevel, and then squeezing them strongly between the long flat
jaws of hot iron pincers, made somewhat like a hairdresser’s
curling-tongs. The pincers should be strong, thick, and just hot enough
to brown paper slightly, without burning it. They may be soldered also
by the heat of boiling water, applied along with skilful pressure. But
in whatever way this process is attempted, the surfaces to be united
should be made very smooth, level, and clean; the least foulness, even
the touch of a finger, or breathing upon them, would prevent their
coalescence. See HORN.
TOUCH-NEEDLES, and TOUCH-STONE, are means of ascertaining the quality of
gold trinkets. See ASSAY.
TOW. See FLAX.
TRAGACANTH, GUM. (_Gomme adracante_, Fr.; _Traganth_, Germ.) See GUM.
TRAVERTINO. See TUFA.
TREACLE, is the viscid brown uncrystallizable syrup which drains from
the sugar-refining moulds. Its specific gravity is generally 1·4, and it
contains upon an average 75 per cent. of solid matter, by my
experiments.
TRIPOLI (_Terre pourrie_, Fr.; _Tripel_, Germ.); rotten-stone; is a
mineral of an earthy fracture, a yellowish-gray or white colour,
composition impalpably fine, meagre to the touch, does not adhere to the
tongue, and burns white. Its analogue, the _Polierschiefer_, occurs in
thin flat foliated pieces, of the above colours, occasionally striped;
soft, absorbent of water; spec. grav. 1·9. to 2·2.
M. Ehrenberg has shown that both of these friable homogeneous rocks,
which consist almost entirely of silica, are actually composed of the
exuviæ or rather the skeletons of infusoria (_animalcula_) of the family
of _Barcillariæ_, and the genera _Cocconema_, _Gonphonema_, &c. They are
recognised with such distinctness in the microscope, that their
analogies with living species may be readily traced; and in many cases
there are no appreciable differences between the living and the
petrified. The species are distinguished by the number of partitions or
transverse lines upon their bodies. The length is about 1/288 of a line.
M. Ehrenberg made his observations upon the tripolis of Billen in
Bohemia of Santafiora in Tuscany, of the Isle of France, and of
Francisbad, near Eger.
The meadow iron ore (_Fer limoneux des marais_) is composed almost
wholly of the _Gaellonella ferruginea_. Most of these infusoria are
lacustrine; but others are marine, particularly the _tripolis_ of the
Isle of France.
According to the chemical analysis of Bucholz, tripoli consists
of--silica, 81; alumina, 1·5; oxide of iron, 8; sulphuric acid, 3·45;
water, 4·55. This specimen was probably found in a coal-field. The
tripoli of Corfu is reckoned the best for scouring or brightening brass
and other metals. Mr. Phillips found in the Derbyshire rotten-stone
(near Bakewell), 86 of alumina, 4 of silica, and 10 of carbon--being a
remarkable difference in composition from the Bohemian.
TUFA, or TUF, is a gray deposit of calcareous carbonate, from springs
and streams.
TULA METAL, is an alloy of silver, copper, and lead.
TUNGSTEN (Eng. and Fr.; _Wolfram_, Germ.); is a peculiar metal, which
occurs in the state of an acid (the _tungstic_), combined with various
bases, as with lime, the oxides of iron, manganese, and lead. The metal
is obtained by reduction of the ore, or the deoxidizement of the acid,
in the form of a dark steel-gray powder, which assumes under the
burnisher a feeble metallic lustre. Its specific gravity is 17·22.
TURBITH MINERAL, is the yellow subsulphate of mercury.
TURF (_Peat_, Scotch; _Tourbe_, Fr.; _Torf_, Germ.); consists of
vegetable matter, chiefly of the moss family, in a state of partial
decomposition by the action of water. Cut, during summer, into
brick-shaped pieces, and dried, it is extensively used as fuel by the
peasantry in every region where it abounds. The dense black turf, which
forms the lower stratum of a peat-moss, is much contaminated with iron,
sulphur, sand, &c., while the lighter turf of the upper strata, though
nearly pure vegetable matter, is too bulky for transportation, and too
porous for factory fuel. These defects have been happily removed by Mr.
Williams, managing director of the Dublin Steam Navigation Company, who
has recently obtained a patent for a method of converting the lightest
and purest beds of peat-moss, or bog, into the four following products:
1. A brown combustible solid, denser than oak; 2. A charcoal, twice as
compact as that of hard wood; 3. A factitious coal; and 4. A factitious
coke; each of which possesses very valuable properties.
Mr. D’Ernst, artificer of fire-works to Vauxhall, has proved, by the
severe test of coloured fires, that the turf charcoal of Mr. Williams is
20 per cent. more combustible than that of oak. Mr. Oldham, engineer of
the Bank of England, has applied it in softening his steel plates and
dies, with remarkable success. But one of the most important results of
Mr. Williams’s invention is, that with 10 cwts. of pitcoal, and 2-1/2
cwts. of his factitious coal, the same steam power is now obtained, in
navigating the Company’s ships, as with 17-1/2 cwts. of pitcoal alone;
thereby saving 30 per cent. in the stowage of fuel. What a prospect is
thus opened up of turning to admirable account the unprofitable bogs of
Ireland; and of producing, from their inexhaustible stores, a superior
fuel for every purpose of arts and engineering.
The turf is treated as follows:--Immediately after being dug, it is
triturated under revolving edge-wheels, faced with iron plates
perforated all over their surface, and is forced by the pressure through
these apertures, till it becomes a species of pap, which is freed from
the greater part of its moisture by squeezing in a hydraulic press
between layers of caya cloth, then dried, and coked in suitable
ovens.--(See CHARCOAL, and PITCOAL, COKING OF.) Mr. Williams makes his
factitious coal by incorporating with pitch or rosin, melted in a
cauldron, as much of the above charcoal, ground to powder, as will form
a doughy mass, which is moulded into bricks in its hot and plastic
state. From the experiments of M. Le Sage, detailed in the 5th volume of
“The Repertory of Arts,” charred ordinary turf seems to be capable of
producing a far more intense heat than common charcoal. It has been
found preferable to all other fuel for case-hardening iron, tempering
steel, forging horseshoes, and welding gun-barrels. Since turf is
partially carbonized in its native state, when it is condensed by the
hydraulic press, and fully charred, it must evidently afford a charcoal
very superior in calorific power to the porous substance generated from
wood by fire.
TURKEY RED, is a brilliant dye produced on cotton goods by MADDER.
TURMERIC, _Curcuma_, _Terra merita_, (_Souchet_, or _Safran des Indes_,
Fr.; _Gelbwurzel_, Germ.); is the root of the _Curcuma longa_ and
_rotunda_, a plant which grows in the East Indies, where it is much
employed in dyeing yellow, as also as a condiment in curry sauce or
powder. The root is knotty, tubercular, oblong, and wrinkled;
pale-yellow without, and brown-yellow within; of a peculiar smell, a
taste bitterish and somewhat spicy. It contains a peculiar yellow
principle, called _curcumine_, a brown, colouring-matter, a volatile
oil, starch, &c. The yellow tint of turmeric is changed to brown-red by
alkalis, alkaline earths, subacetate of lead, and several metallic
oxides; for which reason, paper stained with it is employed as a
chemical test.
Turmeric is employed by the wool-dyers for compound colours which
require an admixture of yellow, as for cheap browns and olives. As a
yellow dye, it is employed only upon silk. It is a very fugitive colour.
A yellow lake may be made by boiling turmeric powder with a solution of
alum, and pouring the filtered decoction upon pounded chalk.
TURNSOLE. See ARCHIL and LITMUS.
TURQUOIS. See LAPIDARY.
TURPENTINE (_Térébinthine_, Fr.; _Terpenthin_, Germ.); is a substance
which flows out of incisions made in the stems of several species of
pines. It has the consistence and gray-yellow colour of honey. It has a
smell which is not disagreeable to many persons, a warm, sharp,
bitterish taste; dries into a solid in the air, with the evaporation of
its volatile oil. It becomes quite fluid at a moderate elevation of
temperature, and burns at a higher heat, with a bright but very
fuliginous flame. There are several varieties of turpentine.
1. _Common turpentine_, is extracted from incisions in the _Pinus abies_
and _Pinus silvestris_. It has little smell; but a bitter burning taste.
It consists of the volatile oil of turpentine to the amount of from 5 to
25 per cent.; and of rosin or colophony.
2. _Venice turpentine_, is extracted from the _Pinus larix_ (larch), and
the French turpentine from the _Pinus maritima_. The first comes from
Styria, Hungary, the Tyrol, and Switzerland, and contains from 18 to 25
per cent. of oil; the second, from the south of France, and contains no
more than 12 per cent. of oil. The oil of all the turpentines is
extracted by distilling them along with water. They dissolve in all
proportions in alcohol, without leaving any residuum. They also combine
with alkaline lyes, and in general with the salifiable bases. Venice
turpentine contains also succinic acid.
3. Turpentine of Strasbourg is extracted from the _Pinus picea_ and
_Abies excelsa_. It affords 33·5 per cent. of volatile oil, and some
volatile or crystallizable resin, with extractive matter and succinic
acid.
4. Turpentine of the Carpathian mountains, and of Hungary; the first of
which comes from the _Pinus cembra_, and the second from the _Pinus
mugos_. They resemble that of Strasbourg.
5. Turpentine of Canada, called Canada balsam, is extracted from the
_Pinus canadensis_ and _balsamea_. Its smell is much more agreeable than
that of the preceding species.
6. Turpentine of Cyprus or Chio, is extracted from the _Pistacea
terebinthus_. It has a yellow, greenish, or blue-green colour. Its smell
is more agreeable, and taste less acrid, than those of the preceding
sorts.
Common Turpentine imported into the United Kingdom, in 1836, 370,981
cwts. 1 qr. 26 lbs.; in 1837, 415,023 cwts. 1 qr. 10 lbs. Retained for
home consumption, in 1836, 341,693 cwts. 18 lbs.; in 1837, 405,772 cwts.
2 qrs. 14 lbs. Duty received, in 1836, _£_74,052; in 1837, _£_87,918.
TURPENTINE, OIL OF, sometimes called essence of turpentine. As found in
commerce, it contains more or less rosin, from which it may be freed by
re-distillation along with water. It is colourless, limpid, very fluid,
and possessed of a very peculiar smell. Its specific gravity, when pure,
is 0·870; that of the oil commonly sold in London, is 0·875. It always
reddens litmus paper, from containing a little succinic acid. According
to Oppermann, the oil which has been repeatedly rectified over chloride
of calcium, consists of 84·60 carbon, 11·735 hydrogen, and 3·67 oxygen.
When oil of turpentine contains a little alcohol, it burns with a clear
flame; but otherwise it affords a very smoky flame. Chlorine inflames
this oil; and muriatic acid converts it into a crystalline substance,
like camphor. It is employed extensively in varnishes, paints, &c., as
also in medicine.
TUTENAG, is an alloy of copper and zinc.
TYPE, (_Caractère_, Fr.; _Druckbuchstabe_, Germ.) The first care of the
letter-cutter is to prepare well-tempered steel punches, upon which he
draws or marks the exact shape of the letter, with pen and ink if it be
large, but with a smooth blunted point of a needle if it be small; and
then, with a proper sized and shaped graver and sculpter, he digs or
scoops out the metal between the strokes upon the face of the punch,
leaving the marks untouched and prominent. He next works the outside
with files till it be fit for the matrix. Punches are also made by
hammering down the hollows, filing up the edges, and then hardening the
soft steel. Before he proceeds to sink and justify the matrix, he
provides a mould to justify them by, of which a good figure is shown in
plate XV., _Miscellany_, _figs._ 2. 3. of _Rees’s Cyclopædia_.
[Illustration: 1157]
A matrix is a piece of brass or copper, about an inch and a half long,
and thick in proportion to the size of the letter which it is to
contain. In this metal the face of the letter intended to be cast is
sunk, by striking it with the punch to a depth of about one eighth of an
inch. The mould, _fig._ 1157., in which the types are cast, is composed
of two parts. The outer part is made of wood, the inner of steel. At the
top it has a hopper-mouth _a_, into which the fused type-metal is
poured. The interior cavity is as uniform as if it had been hollowed out
of a single piece of steel; because each half, which forms two of the
four sides of the letter, is exactly fitted to the other. The matrix is
placed at the bottom of the mould, directly under the centre of the
orifice, and is held in its position by a spring _b_. Every letter that
is cast can be loosened from the matrix only by removing the pressure on
the spring.
A good type-foundry is always provided with several furnaces, each
surmounted with an iron pot containing the melted alloy, of 3 parts of
lead and 1 of antimony. Into this pot the founder dips the very small
iron ladle, to lift merely as much metal as will cast a single letter at
a time. Having poured in the metal with his right hand, and returned the
ladle to the melting-pot, the founder throws up his left hand, which
holds the mould, above his head, with a sudden jerk, supporting it with
his right hand. It is this movement which forces the metal into all the
interstices of the matrix; for without it, the metal, especially in the
smaller moulds, would not be able to expel the air and reach the bottom.
The pouring in the metal, the throwing up the mould, the unclosing it,
removing the pressure of the spring, picking out the cast letter,
closing the mould again, and re-applying the spring to be ready for a
new operation, are all performed with such astonishing rapidity and
precision, that a skilful workman will turn out 500 good letters in an
hour, being at the rate of one every eighth part of a minute. A
considerable piece of metal remains attached to the end of the type as
it quits the mould. There are nicks upon the lower edge of the types, to
enable the compositor to place them upright, without looking at them.
From the table of the _caster_, the heap of types turned out of his
mould, is transferred from time to time to another table, by a boy,
whose business it is to break off the superfluous metal, and that he
does so rapidly as to clear from 2000 to 5000 types in an hour; a very
remarkable dispatch, since he must seize them by their edges, and not by
their feeble flat sides. From the breaking-off boy, the types are taken
to the _rubber_, a man who sits in the centre of the workshop with a
grit-stone slab on a table before him, and having on the fore and middle
finger of his right hand a piece of tarred leather, passes each broad
side of the type smartly over the stone, turning it in the movement, and
that so dexterously, as to be able to rub 2000 types in an hour.
From the rubber, the types are conveyed to a boy, who, with equal
rapidity sets them up in lines, in a long shallow frame, with their
faces uppermost and nicks outwards. This frame, containing a full line,
is put into the dresser’s hands, who polishes them on each side, and
turning them with their faces downwards, cuts a groove or channel in
their bottom, to make them stand steadily on end. It is essential that
each letter be perfectly symmetrical and square; the least inequality of
their length would prevent them from making a fair impression; and were
there the least obliquity in their sides, it would be quite impossible,
when 200,000 single letters are combined, as in one side of the _Times_
newspaper, that they could hold together as they require to do, when
wedged up in the chases, as securely as if that side of type form a
solid plate of metal. Each letter is finally tied up in lines of
convenient length, the proportionate numbers of each variety, small
letters, points, large capitals, small capitals, and figures, being
selected, when the fount of type is ready for delivery to the printer.
The sizes of types cast in this country vary, from the smallest, called
diamond, of which 205 lines are contained in a foot length, to those
letters employed in placards, of which a single letter may be 3 or 4
inches high. The names of the different letters and their dimensions, or
the number of lines which each occupies in a foot, are stated in the
following table:--
Double Pica 41-1/2
Paragon 44-1/2
Great Primer 51-1/4
English 64
Pica 71-1/2
Small Pica 83
Long Primer 89
Bourgeois 102-1/4
Brevier 112-1/2
Minion 128
Nonpareil 143
Pearl 178
Diamond 205
T. Aspinwall, Esq., the American consul, obtained, in May, 1828, a
patent for an improved method of casting printing types by means of a
mechanical process, being a communication from a foreigner residing
abroad. The machine is described, with six explanatory figures, in the
second series of Newton’s Journal, vol. v. page 212. The patentee does
not claim, as his invention, any of the parts separately, but the
general process and arrangement of machinery; more particularly the
manner of suspending a swing table (upon which the working parts are
mounted) out of the horizontal and perpendicular position; the mode of
moving the table with the parts of the mould towards the melting-pot;
the manner of bringing the parts of the mould together, and keeping them
closed during the operation of casting the types. Several other
mechanical schemes have been proposed for founding types, but I have
been informed by very competent judges, Messrs. Clowes, that none of
them can compete in practical utility with that dexterity and precision
of handiwork, which I have often seen practised in their great printing
establishment in Stamford-street.