LEATHER MANUFACTURE. Leather (emir, French; lake, Ger man ; leer, Dutch ; heeler, Danish ; 'oder, Swedish ; omit), Italian ; euero, Spanish ; kusha, Russian.) is prepared from the skins of animals, or, it would perhaps be more correct to say, consists of that substance after it has been chemically changed by the process of tanning. This change is effected by means of a:substance residing in several vegetable matters, to which the name of tannin has been given. When this tannin, which is soluble in water, is applied to the hides of animals from which the hair, epidermis, and any fleshy or fatty parts adhering to them are removed, and which hides then consist wholly of gelatin, also soluble in water, these two soluble substances so unite chemically as to form the wholly insoluble substance called leather. The object of the tanning process is to produce such a chemical change in skins as may render them unalterable by the external agents which tend to decompose them in their natural state ; and in connection with the subsequent operations of dressing, or currying, to bring them into a state of pliability and impermeability to water which may adapt them for the many useful purposes to which leather is applied. Effects in some degree similar are produced by forcing oil or grease into the pores of the skin, or by preparation with alum.
The preparation of skins by tanning or other analogous processes has been practised from the earliest times; and, although it has en gaged the attention of several scientific men, and has been the subject of many curious experiments, it has received less modification from recent improvements in chemical science than many other manu facturing processes. Several plans have been suggested with a view to expedite the process, which, on the old system, is a very tedious one, but having been found to deteriorate the quality of the leather, they have been wholly or partially abandoned; and others, which appear to be more successful, are as yet adopted by a few manufacturers only.
Before noticing the tanning and currying processes, it will be de sirable to glance at the chief kinds of hides and skins converted into leather.
Among the hides of oxen, those supplied by bulls aro thicker, stronger, and coarser in the grain than those of cows; while the hides of bullocks are intermediate between those of the bull and the cow. The thickest and most substantial leather now in general use is that made from the hides of the half-wild cattle of South America. Such leather is employed for the soles of boots and shoes ; for most parts of harness and saddlery ; for leather trunks, buckets, hose for fire engines, and'pump-valves ; for the thick belts used in military accou trements; and for the gloves of cavalry. The thick for merly used as armour, and which was pistol-proof, and would resist the edge of a sword, was made from the hide of the urns or wild bull of Poland, Hungary, and the middle and southern provinces; of Russia ; the animal itself being called Gaffe, whence the common name of the leather made from its hide. Tho skins of ea/ret, though thinner than
those of cows, are thicker than most other kinds of skin which are converted into leather. They are timed or alumed for the use of bookbinders, and are tanned and curried for the upper leathern of boots and shoes. It was formerly customary, in the south-west of Ireland, to slaughter cows when in calf; and the celebrated Limerick gloves were made of the exceedingly fine and delicate skins of the unborn calve,. vary much in quality. A long fleece always in dicates a thin skin ; much of the jelly laid up in that organ being, perhaps, the material from which the fleece is elaborated. When simply tanned, alieepskinn are employed for inferior bookbinding, for leathering bellows, and for various other purposes for which a cheap leather is required. All the as it is termed, which is used for whip-lashes, bags, aprons, &c., is of sheepskin ; as are also the cheaper kinds of of which brushes, gloves, under waistcoats, and other articles of dress are made. Mock or imitation morocco, and most of the other coloured and dyed leathers used for women's and children's shoes, carriage-linings, and the covering of stools, chairs, sofas, writing-tables, &c., are also made of sheepskin. Lamb-skins are mostly dressed white or coloured for gloves ; and those of goat* and kids supply the best qualities of light leather, the former being the material of the best morocco, of all colours, while kid leather, both white and coloured, affords the finest material for gloves and ladies' shoes. Leather from goat-skins, ornamented and sometimes gilt, was formerly used as a hanging or covering for walls. Deer and antdope skins, shamoyed or dressed in oil, are used chiefly for riding breeches. Shamoyed leather breeches were formerly very much used, especially in the army ; but being found unhealthy to horsemen exposed to much wet weather, they were superseded by cloth trousers, except in a few special regiments. Horse-Isides, which, considering their size, are thin, are tanned and curried, and are used by the harness maker, especially for collars ; and occasionally, when pared thin, for the upper leathers of ladies' walking shoes. Doi-skins are thick and tough, and make excellent leather ; but they have been in a great measure superseded, as a material for dress shoes, by horse-leather and by tanned rat-skins. Seal-akins produce a leather similar but inferior to that supplied by dog-skins ; and hog-skins afford a thin but dense leather, which is used exclusively covering the seats of saddles. Porpoise-skins have lately been made, in Canada, into strong and beautiful leather.