Luke Hebert.

The engineer's and mechanic's encyclopædia, comprehending practical illustrations of the machinery and processes employed in every description of manufacuture of the British Empire .. (Volume 2) online

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white, and very abundant fume. It was formerly called the fuming liquor of
Libavius, and is the combination of the muriatic acid and tin.

Tin has a strong affinity for sulphur ; the sulphuret of tin may be formed by
fusing the two substances together : it is brittle, heavier than tin, and not fusible.
It has a blueish colour, a lamellated texture, and is capable of crystallizing.

The white oxide of tin combines with sulphur, and forms a compound called
aurum musivum, or mosaic gold, which is much used for giving to plaster-of-
Paris the resemblance of bronze, and improving the appearance of bronze itself.
It is also occasionally used to increase the effects of electrical machines. See
AURUM MUSIVUM.

Tin possesses the property in a remarkable degree of promoting the fusibility
of other metals, with which it is mixed. Two parts of lead, and one of* tin,
which forms the best plumber's solder, melt at a temperature of little more than
300* Fahr. ; although the melting point of tin alone is 440, and that of lead
612. One part of tin, and two of lead, which forms the inferior plumber's
solder, melt at a lower temperature than the first-mentioned proportions, not-
withstanding the increased quantity of the less fusible metal. Eight parts of
bismuth, (which melts per se at 480,) five of lead, and three of tin, fuse at a
heat below that of boiling water. It is this alloy of which tea-spoons are some-
times made, to surprise those who are ignorant of their nature, by their meltiug
in a cup of hot tea.

The uses of tin are so very numerous, and so well known, as not to need
detailing. We shall advert to only a few ; viz. the fabrication of boilers and
kettles for dyers' use ; the worms of stills ; the drawing of pipes, (erroneously
called pewter) for gas conduits, for beer, wine, vinegar, and other acetous liquids,
which have no action upon pure tin : if the tin were alloyed, it could not be
drawn into sound pipes. Tin forms the principal ingredient in pewter of all
qualities, and enters largely into the greater part of the white alloys in such
extensive use. Immense quantities of tin are used in the fabrication of tinned
iron plates, improperly called tin-plates. We may also here notice a new and most
important application of this pure metal, (under a patent granted to Mr. John
Warner, jun. founder, &c., of Cripplegate, London,) which is that of giving a
perfect and beautiful coat of tin to lead pipes, which thus possess the valuable
qualities of both metals ; viz. the cheapness and flexibility of lead, and the
purity and indestructibility of tin.



793 TOBACCO.

TINNING. The art of covering any metal with a thin coating of tin.
Copper and iron are the metals most commonly tinned. The use of tinning
these metals is to prevent them from being corroded by rust, as tin is not so
easily acted upon by the air or water, as iron and copper are. What are com-
monly called tin-plates, or sheets, so much used for utensils of various kinds,
are, in fact, iron plates coated with tin. The principal circumstance in the art
of tinning is, to have the surfaces of the metal to be tinned perfectly clean and
free from rust, and also that the melted tin may be perfectly metallic, and not
covered with any ashes or calx of tin. When iron plates are to be tinned, they
are first scoured, and then put into what is called a pickle, which is sulphuric
acid diluted with water ; this dissolves the rust or oxide that was left after
scouring, and renders the surface perfectly clean. They are then again washed
and scoured. They are now dipped in a vessel full of melted tin, the surface of
which is covered with fat or oil, to defend it from the action of the air. By this
means, the iron coming into contact with the melted tin in a perfectly metallic
state, it comes out completely coated. When a small quantity of iron only is to
be tinned, it is heated, and the tin rubbed on with a piece of cloth, or some
tow, having first sprinkled the iron with some powdered resin, the use of which
is to reduce the tin that may be oxidated. Any inflammable substance, as oil
for instance, will have in some degree the same effect, which is owing to their
attraction for oxygen. Sheets of copper may be tinned in the same manner as
iron. Copper boilers, saucepans, and other kitchen utensils, are tinned after
they are made. They are first scoured, then made hot, and the tin rubbed on
as before with resin. Nothing ought to be used for this purpose but pure grain
tin ; but lead is frequently mixed with the tin, both to adulterate its quality,
and make it lie on more easily ; but it is a very pernicious practice, and ought
to be severely reprobated.

TITANIUM. A new metal discovered by the Rev. Mr. Gregor, in the
beginning of the present century, in Cornwall. Klaproth subsequently found it
in the red-shorl of Hungary, and gave it the name of titanium. Lampadius
was the first who completely reduced it, which he effected by charcoal only.
The metal was of a dark copper colour, with much brilliancy, brittle, and in
small scales considerably elastic. It tarnishes in the air, and is easily oxidised
by heat : it then acquires a purple tint. It detonates with nitre, and is infusible.
All the mineral acids act upon it with great energy. According to Vauquelin,
it is volatilized by intense heat.

TOBACCO. The dried leaves of a foreign poisonous plant, most exten-
sively cultivated in many parts of the world, to furnish a species of aliment to
the depraved tastes of a large portion of the human race.

Tobacco is a potent narcotic, and also a strong stimulus, and in small doses proves
violently emetic and purgative. The oil is remarkable for its extreme malig-
nancy, and when applied to a wound, is said, by Redi, to be as fatal as the poison
of a viper. The decoction, smoke, and powder are used in agriculture to destroy
insects.

Tobacco being cultivated for the leaves, it is an object to render these as large
and also as numerous as possible, and therefore the most fertile soil is preferred.
It is very sensible to frost. The plants are raised on beds, early in spring, and
when they have acquired four leaves, they are planted in the fields, in well
prepared earth, about three feet distant every way. Every morning and evening
the plants require to be looked over, in order to destroy a worm which some-
times invades the bud. When four or five inches high, they are moulded up.
As soon as they have eight or nine leaves, and are ready to put forth a stalk, the
top is nipped off) in order to make the leaves larger and thicker. After this
the buds, which sprout from the axils of the leaves, are all plucked; and not a
day is suffered to pass without examining the leaves, to destroy a large cater-
pillar, which is sometimes very destructive to them. When they are fit for
cutting, which is known by the brittleness of the leaves, they are cut with a
knife, close to the ground; and, after laying some time, are carried to the
drying shed, where the plants are hung up by pairs, upon lines, having a space
between, that they may not touch one another. In this state they remain to



TOBACCO. 799

sweat and dry ; when perfectly dry, the leaves are stripped from the stalks, and
made into small bundles, tied with one of the leaves. These bundles are laid
in heaps, and covered with blankets. Care is taken not to overheat them, for
which reason the heaps are laid open to the air from time to time, and spread
abroad. This operation is repeated till no more heat is perceived in the heaps,
and the tobacco is then stowed in casks for exportation.

In the manufacture of tobacco, the leaves are first cleansed of any earth,
dirt, or decayed parts; next, they are slightly moistened with salt and water, or
water in which salt and other ingredients have been dissolved according to the
taste of the fabricator. This liquor is called tobacco sauce.

The next operation is to remove the mid-rib of the leaves, which is reserved
to be dried and ground for snuff. The leaves are then manufactured into a
variety of articles, by rolling, twisting, and cutting ; but the chief are the
making of segars, and the cutting the leaves by a machine into fine shreds, for
smoking with pipes, or chewing. . The machine by which the latter operation
is conducted is a very effective instrument, a knife being made to alternate
vertically between grooves, with very great rapidity, while the tobacco leaves,
confined in a channel, are gradually moved forward by a regulated quantity of
motion under the operation of the knife, by which the shreds are uniformly cut
of any required thickness.

A patent for an improvement in the machines used for this purpose, was taken
taken out by Mr. Samuel Wellman Wright, in 1828. Instead of the alter-
nating action of a single knife, Mr. Wright has introduced a series of knives, placed
aa radii to a wheel, which, as they revolve, cut the tobacco into shreds ; much
resembling in its action the chaff-cutting machine in general use, except that
the knives in the latter have a curvature given to them, in order that they may

Fig. 1.




cut with a slicing action, and not with a chop, as in the machine we are about

to describe, which may, however, be easily altered according to our suggestion.

Fig. 1, (above) and Fig. 2 annexed, represent two elevations or views of the



800



TOPOGRAPHY 1 .



machine, one being at right angles to the other, a is the main axis, set in
motion by the drum I; c c is a fly-wheel having hinges d d, to which the
cutters e e are attached by screws, (these are best seen in Pig. 1 ;) other screws//
are employed to adjust and set the hinges d d, so that the cutters shall press
close to the front of the box g, in which the tobacco is placed ; h h are two
screws for pressing the tobacco down ; and It a screw, by the turning of which
it is pushed forward towards the cutters. This screw is supported in plummer
blocks / I, and works in a nut fixed in a massive block m, from which two strong
bars proceed to another block in the box g, which presses the tobacco forward
by the revolution of the screw. On the axis of the screw is a treble pulley,
driven by a cat-gut band from another pulley o, on the axis of a, which admit?



Fig. 2




of the velocity of the screw being varied according as the tobacco is required to
be cut fine or coarse. The treble pulley is made to carry round a screw by a
sliding clutch p in the axis of the screw, which is kept pressed by a fork lying
in grooves in the clutch.

When the box requires a fresh supply of tobacco, the fork is turned back from
the clutch, and a weight s, which has been wound upon the axis of a winch t
descends, and turning the screw in the reverse direction, brings back the block
to the other end of the box g.

TODDY. A juice drawn from various kinds of palms, by cutting off such
branches as nature intended to bear fruit, and receiving from the wound the sap
designed for the nourishment of the future crop. This juice being fermented
and distilled with some other ingredients, forms the celebrated spirituous Jiquor
called arrack or rack.

TOMBAC. An alloy of copper, with about one-sixth part of zinc.

TOPAZ. A precious stone found in Saxony, Bohemia, Siberia, and Brazil,
mixed with other minerals, in granitic rocks. The yellow topaz of Brazil
becomes red when exposed to a strong heat in a crucible ; that of Saxony
becomes white by the same process, showing that the colouring matter of each
is not the same.

TOPOGRAPHY. A description or draft of some tract of land, as that of a
city, town, villa, field, &c. as set out by surveyors.



TRANSFERRING. 801

TORMENTOR. An instrument much used in tillage, sometimes for breaking
down the stiff clods, and at other times for skimming the surface turf, for the
purpose of burning. It resembles a harrow in its general appearance, but runs
upon wheels, and each tire is furnished with a hoe or share that enters and cuts
up the ground.

TORPEDO. A sub-marine apparatus, invented by Robert Fulton for the
purpose of destroying ships. It consisted of a vessel or case, charged with
combustible matter, which he proposed to transfix by a harpoon to the bottom
of a ship, by diving underneath it in his " nautilus," in which he sometimes
remained under water for an hour at a time. Buonaparte employed him to
apply his " infernal machine " to some British ships in the Channel ; but Fulton
failed in his attempts to fix his torpedoes ; whereupon the impatient consul of
the French republic regarded him as a quack, and dismissed him, unjustly
observing, " Get Americain tait un charlatan, un escroc qui voulait seule*-
ment attraper del'argeiit."

TORTOISESHELL. The shell of the tortoise, a testaceous animal, used in
the fabrication of many articles of ornament and utility. The comb-makers
and horn-turners of France, Holland, and Germany, make use of the parings
and clippings of horn and tortoiseshell, in the manufacture of snuff-boxes, and
a variety of elegant articles and toys. They first soften the material in boiling
water, so as to be able to press it into iron moulds, and then, by means of heat,
unite them intimately into one mass. Care must be taken that the heat be not
so powerful as to scorch the material ; and grease must be carefully avoided, as
that prevents their union.

TOURNIQUET. A surgical instrument employed to stop bleeding.

TOW. Coarse undressed hemp, or old rope reduced to the filamentous state.

TRAGACANTH. A gum, also called gum adracant, and gum dragon, is
the produce of the above, and some other shrubs. The gum is brought to us in
long and slender pieces, of a flatted figure more or less ; and these not straight,
or rarely so, but commonly twisted or contorted various ways, so as to resemble
worms. We sometimes meet with it, like the other vegetable exudations, in
roundish drops, but these are much more rare. It is moderately heavy, of a firm
consistence, and, properly speaking, very tough rather than hard, and is extremely
difficult to powder, unless first carefully dried, and the mortar and pestle kept
dry. Its natural colour is a pale white, and in the cleanest pieces it is something
transparent. It is often, however, met with of a brownish tinge, and of other
colours still more opaque. It has no smell, and very little taste, but what it
has is disagreeable. Taken into the mouth, it does not grow clammy,
and stick to the teeth, as gum arabic does, but melts into a kind of very soft
mucilage. It dissolves in water but slowly, and communicates its mucilaginous
quality to a great quantity of that fluid. It is by no means soluble in oily or
spirituous liquors, nor is it inflammable. It is brought to us from the island of
Crete, and from several parts of Asia. It is to be chosen in long twisted pieces
of a whitish colour, free from all other colours, which must be rejected.

TRAMMEL. An instrument employed by artificers and draftsmen for
drawing ellipses. It consists of a cross with two grooves at right angles to each
other, and a beam containing two pins that are made to traverse in the grooves
by the revolution of the bar ; the bar carries a pencil that describes an ellipse.

TRANSFERRING of engravings and lithographic drawings from the
paper, on to wood, or other material, is thus performed. The print is first
placed in a vessel of water, until it is completely saturated, which will be in
about five or ten minutes, and then placed between blotting paper to remove
the superabundant water from its surface. It is then varnished by a brush, and
applied immediately to the wood, which has been previously varnished and
allowed to dry. The print, thus applied, may be subjected to the pressure
necessary to effect its complete adhesion, by spreading over it a sheet of paper,
and rubbing this with the hand. The paper on which the print was made may
then be peeled off by rubbing it cautiously with the moistened fingers, and when
wholly removed, a coat of varnish mnst be applied to the print. When coloured
prints are to be transferred, an acid solution must be used instead of water, to

VUL. n. 5 i



802 TREPANNING.

destroy the size which exists in the paper. This solution may be composed of
two-thirds of vinegar and one-third of water, and is to be applied only to the
back of the print. If the article is to be polished, apply several coats of
varnish, allowing each to dry before the application of another; and then nib
the surface with a piece of woollen cloth and pumice stone reduced to im-
palpable powder. When the surface becomes smooth, the process may be con-
tinued with a fine cloth, and the finest tripoli with olive oil.

TRANSPARENCIES. Is a term ordinarily applied to pictures, prepared
with semi-transparent or translucent materials, and illuminated at the back, so
as to exhibit them at night. The art of preparing them is as follows :

The paper (or other material) must be fixed in a straining frame, in order
to place it between the eye and the light, when required. After tracing the
design, the colour must be laid on, in the usual method of stained drawings.
When the tints are got in, place the picture against the window on a pane of
glass framed for the purpose, and begin to strengthen the shadows with Indian
ink, or with colours, according as the effect requires ; laying the colours some-
times on both sides of the paper, to give greater force and depth of colour. The
last touches for giving final strength to shadows and forms, are to be done with
ivory-black or lamp-black prepared with gum-water, as there is no pigment so
opaque and capable of giving strength and decision. When the drawing is
finished, and every part has got its depth of colour and brilliancy, being perfectly
dry, touch very carefully witli spirits of turpentine, on both sides, those parts
which are to be the brightest, such as the moon and fire ; and those parts
requiring less brightness, only on one side. Then lay on immediately, with a
pencil, a varnish, made by dissolving one ounce of Canada balsam in an equal
quantity of spirit of turpentine. Be cautious with the varnish, as it is apt to
spread. When the varnish is dry, tinge the flame with red lead and gamboge,
slightly touching the smoke next the flame. The moon must not be tinted with
colour. Much depends upon the choice of the subject. The great point to be
attained is a happy coincidence between the subject and the effect produced.
The fine light should not be too near the moon, as its glare would tend to injure
her pale silver light ; those parts which are not interesting should be kept in an
undistinguishable gloom; and where the principal light is, they should be
marked with precision. Groups of figures should be well contrasted ; those in
shadow crossing those that are in light, by which means the opposition of light
against shade is effected,

TREAD-MILL. Is a mill worked by the weight of persons treading upon
the first movement, which is usually a wide cylindrical wheel, having upon its
periphery a sei-ies of projecting steps or boards, resembling those of a water-
wheel. The weight of the individuals continually climbing these steps, causes
it to turn round, and put in motion any other machinery, by means of ordinary
gear. Tread-mills are now resorted to pretty generally in this country, as a
means of prison discipline ; and the result has been, that men cannot be found
to work this species of machine out of prison, conceiving the employment to be
degrading. The Chinese raise water by a similar contrivance for irrigation.

TREE-NAILS. Are cylindrical wooden pins or bolts, used to fasten planks
to timbers, especially in ship-building.

TREPANNING. Is a surgical operation for opening the skull in cases of
fracture ; a description of which does not form a part of the plan of this work,
and we only introduce the subject, in order to describe the instrument by which
it is performed, as the principle of its construction may be advantageously
applied to other purposes. represents a thin steel tube, the edge of which is
serrated into fine sharp teeth, forming thereby an annular saw; it is fixed in a
stout brass collar b, which is adjusted to the end of the axis c, and revolves
(Herewith, when turned by the winch d. There are three screw supports, e e, to
the upper and lower plates, which form the frame, and the distance of the
plates from each other is adjustable by the screws e c. The end of the axis c
is formed into a pointed drill, and extends a little beyond it.

The case which contains this instrument is provided with several sized annular
saws, drills, and screws. The surgeons in using this instrument, (after removing



TRUCK. 803

a portion of the scalp,) cut out a circular piece of bone, the central pin or drill
preventing it from slipping, and the perforation thus made by the drill serves




afterwards foi the insertion of a screw, by which the removal of the circular
piece of bone is ensured. Access is thus gained under the arch of the skull
for removing the splinters or raising the depressed parts, occasioned by the
fracture. Circular saws of this description have already been applied for
cutting out pillars and concentric cylinders from solid blocks of stone ; and
our mechanical readers will find out many other valuable uses for the applica-
tion of a similar instrument.

TRIANGLE. In geometry, a figure bounded or contained by three lines or
sides, and which consequently has three angles, from whence the figure takes
its name.

TRIANGULAR-COMPASSES. Are compasses with three legs, whereby
to take off any triangle at once; much used in the construction of maps,
globes, &c.

TRUCK. A small wheel carriage to be moved by hand ; a species of barrow
with two wheels ; they are made in a great variety of forms, to adapt them to
their peculiar objects, such as the moving of sacks, bags, casks, cases, lead, iron,
copper, stone, &c. &c. To describe those simple, well-known machines, would
be of little utility; we therefore confine our attention to a very ingeniously
contrived truck, invented by Mr. S. W. Wright, and which is employed at the
West India Dock Company's warehouses, for moving and stacking the sugar
hogsheads in tiers ; an operation previously performed by other mechanical
means, and technically called " riding the hogsheads."

a a a shows the frame of the truck, mounted upon four wheels, on which it
runs ; b b is the skid upon which the hogshead is raised into the position repre-
sented; c c d d are levers supporting the skid, and turning upon fulcrums at o o,
to which are attached two toothed sectors e. e, that are acted upon by two
pinions fixed near to the ends of the axis /; this axis carries a click-box a,
which is worked by a lever h attached to it: i is a ratchet-wheel on/, I a pall,
acting on the same to prevent it receding; m a bent lever, for lifting by inter-
mediate chains, the palls, and click, which allows the skid to descend to the level
of the upper side of the frame a a; n is a handle for men to draw the truck.
There are two ratchet wheels, and two palls, though only one can be seen in the
perspective view given.

A crane is employed to lift the hogsheads upon the truck ; the latter is then
wheeled off to the pile, where the hogshead is raised by alternately raising and
depressing the lever h, which turning round the axis /, causes the pinions fixed
upon it to raise the toothed sectors and levers that support the skid ; a reaction
being prevented by the palls falling into the teeth of the ratchet-wheels as they
turn round. We object generally to an intermitting motion, where a continuous
one can be applied ; and we can see no difficulty in applying it in the present
instance by the introduction of winches in the usual way. Notwithstanding the
slight imperfections that may at present attach to this machine, it must be pro-
nounced an original and effective contrivance ; and so sensible (it was reported)
were the directors of the establishment before mentioned of the advantages
attending the use of the new truck in their warehouses, as to present the
inventor with the sum of a thousand pounds, over and above the amount of their
contract for a great many of the machines



804



TRUNNIONS.




TRUMPET. The loudest of all portable wind instruments ; of which there
are various kinds. In their most simple form, they consist of a metallic tube,
with a large bell-shaped aperture at one end for the emission of the sound, and
a mouth-piece at the other, adapted for blowing into it by the lips. See the
words EAR-TRUMPET and SPEAKING-TRUMPET.

TRUNDLE. A small wheel with staff teeth ; also called a lantern or



Online LibraryLuke HebertThe engineer's and mechanic's encyclopædia, comprehending practical illustrations of the machinery and processes employed in every description of manufacuture of the British Empire .. (Volume 2) → online text (page 117 of 135)