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.

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, in Dorsetshire, and in Devonshire, at Newton Abbot. 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 of 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 50 gross in from 8 to 12 hours. A workman and a child can easily make 5 gross of pipes in a day.

No tobacco-pipes are so highly prized as those made at 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.

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. 1815

and 1816, 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 1815 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 r, in fig. 1816 (the dotted circle representing the cylinder). These ribs are perforated with occasional apertures, as shown in fig. 1815, 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. 1815, by an iron plate plastered over with fire-clay; above this it is left open, and shut merely with temporary brick-work 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 bowis 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 eight or nine 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."

TOLUIDINE. CHoN. A volatile base isomeric with lutidine, formed from toluole, by processes analogous in all respects to those by which aniline is produced from benzole.-C. G. W.

TOLUOLE. C4H8. Syn., Hydruret of toluenyle. A hydrocarbon produced in the destructive distillation of the resin of Tolu. It is also produced by the decomposition of toluylic acid by baryta at a high temperature. Coal naphtha contains it in large quantity. For its physical properties, see CARBO HYDRIDES.C. G. W.

TOLU is a brownish-red balsam, extracted from the stem of the Myroxylon 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.

TOMBAC. White copper.

former and 15 of the latter.

An alloy of copper and zinc; 85 per cent. of the

TON. An Fnglish weight of 20 cwt., according to the statute, or 2240 lbs. It varies in different districts :

Contributions to the History of the Cocoa-nut Tree. By Henry Marshall, Esq., Deputy Inspector of Hospitals.

South Wales, from 2400 lbs. to 2618 lbs.

Ayrshire, from 2464 lbs. to 2520 lbs.

North Staffordshire, coal, 2400 lbs.

Do. do.

stone, 2520 lbs.

Copper ores are sold by the ton of 21 cwt. of 112 lbs. or 2352 lbs.

In Newcastle the leases are by the ton of 440 bolls of 36 gallons each =48 tons, 11 cwt. 2 qrs. 17 lbs. statute.

TONKA BEAN. The fruit of the Dipterix odorata, affords a concrete crystalline volatile oil (steuroptene), called coumarine by the French. It is extracted by diges tion with alcohol, which dissolves the stearoptene 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.

The

TOOTH FACTORY. Teeth are made of the best ivory; the following, how. ever, is one of the processes adopted for the artificial manufacture of teeth. Pure crystallised quartz is calcined by a moderate heat. When taken from the fire it is thrown immediately into cold water, which breaks it into numberless pieces. larger pieces are broken into smaller, and the whole put into a mill, which is itself made of quartz. Here the pieces of calcined quartz are ground up into fine powder. Next fluor spar, free from all impurities, is ground up in like manner into a fine powder. Artificial teeth are composed of two parts, called the body and enamel. The body of the tooth is made first, the enamel is added last.

The next step is to mix together nearly equal parts, by weight, of the powdered spar and quartz. This mixture is again ground to a greater fineness. Certain metallic oxides, as of tin, are now added to it, for the purpose of producing an appropriate colour, and water and china clay to make it plastic and give it consistence. This mixture resembles soft paste, which is transferred to the hands of females, who are engaged in filling moulds with it, or otherwise working upon it. After the paste has been moulded into proper shape, two small platina rivets are inserted near the base of each tooth, for the purpose of fastening it (by the dentist), to a plate in the mouth. They are now transferred to a furnace, where they are "cured," as it is technically called; that is, half baked or hardened. The teeth are now ready to receive the enamel, which is done by women; it consists of spar and quartz which has been ground, pulverised, and reduced to the state of a soft paste, which is evenly spread over the half-baked body of the tooth by means of a delicate brush. The teeth must be next subjected to an intense heat. They are put into ovens, lined with platina and heated by a furnace, in which the necessary heat is obtained. The baking process is superintended by a workman, who occasionally removes a tooth to ascertain whether those within have been sufficiently baked. This is indicated by the appearance of the tooth. When they are done, the teeth are placed in jars ready for use. An experiment tests the hardness of these artificial teeth. One of them taken indiscriminately out from a jar-ful is driven without breaking into a fine board, until it is even with the surface of the wood.

TOPAZ. The fundamental form is a scalene 4-sided pyramid; but the secondary forms have a prismatic character, and are frequently observed in oblique 4-sided prisms, acuminated by 4 planes. The lateral planes of the prism are longitudinally striated. Fracture conchoidal, uneven; lustre vitreous; colours, white, yellow, green, blue, generally of pale shades. Hardness 8; spec. grav. 3.5. Prismatic topaz

consists, according to Berzelius, of alumina, 57-45; silica, 34·24; fluoric acid, 7·75. In a strong heat the faces of crystallisation, but not those of cleavage, are covered with small blisters, which however immediately crack. With borax, it melts slowly into a transparent glass. Its powder colours the tincture of violets green. Those crystals which possess different faces of crystallisation on opposite ends acquire the opposite electricities on being heated. By friction it acquires positive electricity.

Most perfect crystals of topaz have been found in Siberia, of green, blue, and white colours, along with beryl, in the Uralian and Altai mountains, as also in Kamtschatka; in Brazil, where they generally occur in loose crystals, and pebble forms of bright yellow colours; and in Mucla in Asia Minor, in pale straw-yellow regular crystals. They are also met with in the granitic detritus of Cairngorm in Aberdeenshire. The blue varieties are absurdly called oriental aquamarine by lapidaries. If exposed to heat, the Saxon topaz loses its colour and becomes white; the deep yellow Brazilian varieties assume a pale pink hue, and are then sometimes mistaken for spinelle, to which, however, they are somewhat inferior in hardness. Topaz is also distinguishable by its double refractive property. Tavernier mentions a topaz, in the possession of the Great Mogul, which weighed 157 carats, and cost 20,000l. sterling. There is a specimen in the Museum of Natural History at Paris which weighs 4 ounces 2 gros. Topazes are not scarce enough to be much valued by the lapidary.

TORBITE. A new preparation of PEAT. The following description of the works established at Horwich in Lancashire, is from a communication made by Mr. D. K. Clark, C.E. to the British Association. According to the system matured and established at Horwich, the peat, as it comes from the bog, is thrown into a mill expressly constructed, by which it is reduced to a homogeneous pulpy consistency. The pulp is conveyed, by means of an endless band, to the moulding machine, in which, while it travels, it is formed into a slab and cut into blocks of any required size. The blocks are delivered by a self-acting process on a band, which conveys them into the drying chamber, through which they travel forwards and backwards, on a series of endless bands, at a fixed rate of speed, exposed all the time to the action of a current of heated air. The travelling bands are so arranged that the blocks of peat are delivered from one to the other consecutively, and are by the same movement turned over in order to expose fresh surfaces at regular intervals to the action of the drying currents, so that they emerge from the chamber dry, hard, and dense. To the peat substance thus treated, the name of "torbite" has been given from the Latin torbo, by which name peat is constantly mentioned in ancient charters.

The next stage in the process is the treatment of the torbite in close ovens, when it may either be converted into charcoal for smelting purposes, or may be only partially charred for use as fuel for generating steam, or in the puddling furnace.

The whole of the Horwich system has been planned with a view to the utmost economy of time and labour. The peat is nearly altogether automatically treated by steam power; introduced at one end, it issues from the other in the form of charcoal within twenty-four hours after it is excavated from the bog, and the manual labour expended is almost entirely limited to the first operation of digging, consequently the actual outlay in labour and fuel in the production of the charcoal does not exceed from 10s. to 12s. per ton; but in addition to the economy thus effected by charring in close ovens, a considerable quantity of valuable chemical products are yielded, as ammonia, acetic acid, pyroxylic spirit, paraffine oils-the sale of which alone nearly covers the expenses of the whole process.

The fatty matter separated by distillation forms an excellent lubricating grease, the yield of which averages about five per cent. of the weight of charcoal produced in its crude state. It has been sold for 127. per ton at Horwich.

The charcoal made from torbite is extremely dense and pure; its heating and resisting powers have been amply and severely tested, and with the most satisfactory results. At the Horwich works pig iron has been readily melted in a cupola. About eighty tons of superior iron have been made with it in a small blast furnace measuring only six feet in the boshes, and about twenty-six feet high. The ore smelted was partly red hematite and partly Staffordshire, and the quantity of charcoal consumed was one ton eleven hundredweights to the ton of iron made, but in a larger and better constructed furnace, considerably less charcoal will be required. It has also been tried in puddling and air furnaces with equally good results, considerably improving the quality of the iron melted. For this purpose the fuel was only partially charred, in order not to deprive it of its flame, which is considerably longer than that from coal. Some of the pig iron made at Horwich was then converted into bars; which were afterwards bent completely double when cold without exhibiting a single flaw. Messrs. Brown and Lennox, in testing this iron for chain cables, have reported that its strength was proved to be considerably above the average strength of the best brands.

TORTOISE-SHELL, or rather scale; 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 thirteen in number, and may be readily separated from the bony parts 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.

Tortoise-shell is manufactured into various objects, partly by cutting out the shapes and partly by agglutinating portions of the shell by heat. When the shell has become soft by dipping it in hot water, and the edges are in the cleanest possible state without grease, they are pressed together with hot flat tongs, and then plunged into cold water, to fix them in their position. The teeth of the larger combs are parted in their heated state, or cut out with a thin frame saw, while the shell, equal in size to two combs, with their teeth interlaced, as in fig. 1817, is bent like an arch in the direction of the length of the teeth, as in fig. 1818. The shell is then flattened, the points are separated with a narrow chisel or pricker, and the two combs are finished, while flat, with coarse single-cut files and triangular scrapers. They are finally warmed, and bent on the knee over a wooden mould, by means of a strap passed round the foot, just as a shoemaker fixes his last. Smaller combs of horn and tortoise-shell are parted, while flat, by an ingenious machine, with two chisel-formed cutters placed obliquely, so that each cut produces one tooth. See Rogers's comb-cutting machine, Trans. Soc. Arts, vol. xlix. part 2., since improved by Mr. Kelly. In making the frames for eye glasses, spectacles, &c. the apertures for the glasses were formerly ent out to the circular form with a tool something like a carpenter's centre-bit, or with a crown saw in the lathe. The discs so cut out were used for inlaying in the tops of

boxes, &c. This required a piece of shell as large as the front of the spectacle; but a piece one third of the size will now suffice, as the eyes are strained or pulled. A long narrow piece is cut out, and two slits are made in it with a saw. The shell is then warmed, the apertures are pulled open, and fastened upon a taper triblet of the appropriate shape; as illustrated by figs. 1820, 1821 and, 1822. The groove for the edge of the glass is cut with a smail circular cutter, or sharp-edged saw, about three eighths or half an inch in diameter; and the glass is sprung in when the frame is expanded by heat.

In making tortoise-sheel boxes, the round plate of shell is first placed centrally over the edge of the ring, as in fig. 1823; it is slightly squeezed with the small round edgeblock g, and the whole press is then lowered into the boiling water: after immersion for about half an hour, it is transferred to the bench, and g is pressed entirely down, so as to bend the shell into the shape of a saucer, as at fig. 1825, without cutting or injuring the material; and the press is then cooled in a water-trough. The same processes are repeated with the die d, which has a rebate turned away to the thickness of the shell, and completes the angle of the box to the section fig. 1824, ready for finishing in the lathe. It is always safer to perform each of these processes at two successive boilings and coolings. Two thin pieces are cemented together by