Chamois, or Shawl leather.—Another kind of leather is that in which oil or grease is forced into the porea of the skin, to take the place of the animal matter. This kind of leather takes its name from a fine soft leather prepared from the skin of the chamois goat ; and the process by which it is made is called shamoging or shamniying. Such leather was formerly very much used as an article of clothing, especially by soldiers; and it is still applied to several useful purposes, for which its peculiar softness and pliability render it valuable. Wash-leather may be cited as a common example of this kind of preparation. The skins of deer, goats, sheep, &c. are dressed in this way ; and much shamoyed leather is made from the inferior or least regular portion of split skins, in cases where the grain side has been taken off carefully of a uniform thickness fur preparation in a different way. In general. when whole skins are shamoyed, the grain surface 18 removed by gcraping or rubbing with pumice-atone, After the usual preparation with lime-water, and subsequent washing in a sour infusion of bran or some similar liquor, to remove the lima and open the pores, the skins are made as dry as possible by wringing or pressing them, and are then exposed to the action of fulling-stoeks. These consist of heavy wooden hammers, faced with copper, and set in motion by connection with a revolving shaft. The leather, or rather a roll of the skins which are to be made into leather, is placed in a trough, and beaten by the hammers until it is perfectly dry. Cod-oil is then poured upon the skins, and forced into their pores by the action of t ie 1 ammers or stocks; the form of the trough being such that the s`cins gradually turn themselves over and over during the operation, to render the beating uniform. When the oil is thoroughly beaten in, the skins are hung up to dry, after which they are returned to the trough to receive a fresh supply of oil and a repetition of the beating. This is repeated eight or nine times, until two or three gallons of oil have been im bibed by one hundred skins ; and when they are sufficiently impregnated with it, they are placed in large tubs, or hung up in close heated chambers, in which they undergo a kind of fermentation, by which the pores are distended, and the action of the oil upon the fibres is com pleted. Finally, the skins are immersed in a weak solution of potash, which removes whatever excess of oil may have remained in the leather, forming with it a saponaoeous mixture. They are then hung up iu the open air to dry.
Carrying and Leather Dressing.—Currying is the general name given to the various operations of dressing leather after the tanning is com pleted, by which the requisite smoothness, lustre, colour, and supple. ness are imparted, to adapt it to the various purposes of the shoemaker, the coach and harness maker, the upholsterer, and others. Every kind of tanned leather not intended for soles, or similar coarse purposes, is generally curried before being delivered to the workman who fashions it. The operation commences by moistening the leather with water, and beating it well upon a strong hurdle with a mallet or mace. After this beating, by which the stiffness is destroyed, the leather is laid over an inclined board, and scraped, cleaned, and pared down on the flesh aide, by the careful application of various two-handled knives. It is then thrown again into water, and well scoured by rubbing the grain or hair side with pumiee-stone, or with a piece of slaty grit. The leather is next rubbed with the pommel, a rectangular piece of hard wood, about twelve inches long and five broad ; the currier uses several of these instruments, with grooves of various degrees of fineness, and also, for some purposes, pommels of cork which are not grooved at all. In using the pommel, the object of which is to give grain and pliancy to the skins, the leather is first folded with the grain side inwards and rubbed strongly with it ; and subsequently it is rubbed with the pom mel upon the grain side, without being doubled or folded. The leather is then. scraped with tools applied nearly perpendicular to its surface and worked forcibly with both hands, to radnes such parts as may yet be left too thick to a uniform substance. Finally, the leather is dressed with the round knife, a singular instrument shaped somewhat like a saucer, with a cutting edge, and with a hole in the centre for intro ducing the hands of the workman. It is usually from ten to twelve inches in diameter, with the central hole about four or five inches. This tool is applied with its concave aide downwards ; and with it, while the leather is stretched over a cylindrical wooden beam, the currier dexterously pares off the coarser fleshy parts of the skin. The currier uses occasionally polishers of smooth wood or glass for rubbing the surface of the leather ; and, when the leather is intended for the use of the shoemaker, he applies to it some kind of greasy composition called dubbing or stailiug.
Leather is occasionally dressed "black on the grain," or having the hair or grain instead of the flesh aide coloured. The currying opera tions in such a else are similar to those above described; but the first blacking is applied to the wet skin immediately after scouring, by rubbing it with a solution of copperas. A brush dipped in an alkaline liquor is then passed over the surface, and an iron slicker is used to make the grain coma out as fine as possible. It is then stuffed with oil. and, when dry, seasoned, or rubbed over with a brush dipped in copperas-water, on the grain, until it is perfectly black ; after which it is slicked with a gritstone, to remove any wrinkles and smooth down the coarse grain. The grain is finally raised by repeatedly rubbing over the surface, in different directions, with the pommel or graining board.
In connection with the dressing of leather, we may briefly notice Japanned, Russia, and Shagreen leather. Japanned leather of various kinds is used in coach-making, harness-making, and for various other purposes. What is ordinarily termed ' patent leather' is covered with a coat of elastic japan, which gives a surface like polished glass, impermeable to water ; and hides prepared in a more perfectly elastic mode of japanning, which will permit folding without cracking the surface, are called enamelled leather.' Such leather is usually made
black, but may be produced of any required colour. A composition, made of boiled linseed oil, vegetable black, and Russian blue, is rubbed as a thick paste on the surface of the leather by hand ; it is dried in a stove heated to 150" or 170° Fehr This is repeated from three to seven times, according to the excellence of the article s to be produced. Boots and shoes are sometimes made of thin enamelled leather, and they possess the advantage of never requiring blacking, water being sufficient to remove any dirt which impairs their gloss. .Russia leather called by the Russians themselves jitiant, is usually dyed red with the arotuatie saemlerawood, and is celebrated for being free from mould in damp situations, and not only being proof against insects, but repelling them by it. odour, so as to preserve books in the binding of which it is used. The skins are freed from the hair or fleece by steeping them in an ash-lye, then rinsed, fulled, and fermented in a Kt/per steep, after having been washed in hotavater, for • week or more, to muse or open their pores. They are then cleaned, by working them upon the horse, on both sides. They are next snaked for forty eight hours in a bath composed of water mixed with a paste of rya Sour. The skins, when taken out of the bath, are left in tuba for fifteen days, and then washed. Being thus prepared for the action of the astringent or tanning juices, they are immersed in a boiler con taining • hot decoction of willow bark, in which they are handled and pressed for half an hour. This manipulation is repeated twice a day for a week, after which the tanning infusion is renewed, and tho proems is repeated on the mime skins for another week. The skins are then exposed to the air to dry, dyed, and curried with the empyrrumatio oil of the hark of the birch-tree. Shagreen is a peculiar kind of leather, or rather of prepared skin, formerly much used fbr the covers of watch-cases, mathematical-instrument cases, &e. The akin, after being soaked in water and scraped to remove the hair, Is stretched upon • frame, and the grain-aide is strewed with the hard round seeds of the a/abata, or goose-foot. A felt being laid over these, they aro trodden deeply into the soft yielding skin; after which the frames are so placed in the shade as to allow the skins to dry slowly, when the seeds may be shaken out without violence, leaving the skin in • hard horny state, covered with deep indentations. The surface is then rasped or rubbed down with iron tools, nearly to the bottom of the holes or indentations, the akin during this opera tion being Laid upon a block covered with wool The skins are next softened, first with water, and then with a warm alkaline ley, and are heaped, while warm and wet. upon each other ; and by this softening the depressed parts of the skin rise to their former elevation, forming prominent points wherever depressions had been made by the seeds. The skins are then salted and dyed, after which they are finished with oil or suet Great difficulties present themselves in the way of any application of machinery to the dressing of leather, in consequence of the varying hardness, thickness, and texture, not only of different skins, but of different parts of the same skin ; yet the great amount of time and manual labour involved in the polishing and graining of morocco and other ornamental leathers has led to some ingenious contrivances for this purpose. Hebert contrived a machine consisting essentially of a stiff circular frame or wheel, eight feet in diameter, revolving hori zontally upon a vertical axis, and carrying, on the underside of its peri phery, a series of circular polishers or grainera; but it was not brought much into um. Leather-splitting machines, by which even very thin skins may be divided into two thicknesses, each capable of being dressed as • perfect skin, have called forth much ingenuity of contrivance. Before such machines were introduced, the reduction of thicknom necessary to bring many of the finer kinds of leather to the requisite tenuity was effected solely, as it still is partially, by paring or shaving the mesh side with a knife worked by hand, an operation occupying much time, and requiring great nicety to prevent cutting through the skin. The part shaved oil, also, being necessarily in small pieces, was only available for the making of glue. By the use of a machine, however, the best portion of the leather, that with the grain side, is cat of • much more uniform thickness, and with hies risk of injury ; the removed portion is mkt it off in a more useful form ; and the whole operation is conducted inure rapidly. One such machine is so accurately constructed, that it has been made to split sheep-skins into three equal parts; one of which, Jhat on the grain-aide, might be used as leather, the middle portion converted into parchment, and the nliee on the flesh side, being unequal in thickness, and therefore unfit for any better use, being used for gluemaking. In this machine, the skin is drawn between two revolving rollers, and is presented, a* it emerges from their grasp, to the edge of a long and very sharp knife, which is kept continually moving a little backwards and forwards with great velocity. As a skin of unequal thickness could not be grasped in the proper manner between two perfectly true and rigid rollers, the upper roller, instead of being solid, is composed of a number of circular discs or rings of metal, about half an inch thick, slipped on to an axis; by this contrivance the upper roller is enabled to adapt its surface to that of the skin, which is everywhere pressed with an equal force, due to the weight of the discs of which the upper roller is composed. This machine will split a sheep-skin of the ordinary size in about two minutes, during which time the knife makes from two to three thousand vibratory motions to and fro.