THE TECHNOLOGIST. [Nov. 1, 1864. 



154 ON CHEMISTRY APPLIED TO THE ARTS. 



whole set in motion, and whilst the hides are thus tossed ahout, a 

 current of warm air is passed through the drums, which carries off the 

 moisture and allows the grease to penetrate the hide. By this means 

 thick hide leather can be stuffed in four or five days. 



Split Leather. — A large branch of trade has sprung up within a few 

 years owing to the invention of machinery for splitting hides, skins, 

 and kips, by which the quantity of leather has been considerably in- 

 creased, though I am afraid this has been done at the expense of its 

 quality. 



Fancy Leathers. — Allow me now to give you a slight insight into the 

 methods of preparing various fancy leathers, such as Morocco, Russia, 

 enamelled, tawed, or kid leather, used for soldiers' belts, gloves, &c, 

 and, lastly, oiled leathers, used for washleather, gloves, &c. Until the 

 middle of the eighteenth century Morocco leather was wholly imported 

 from that country, for it was in 1735 that the first Morocco works were 

 established in Paris, and similar manufactories were soon set up in 

 various parts of the Continent and in this country. The process by 

 which Morocco leather is prepared is as follows : — The goat and sheep 

 skins, which are especially used for this branch of manufacture, are 

 softened, fleshed, unhaired, and raised or swelled by methods similar 

 to those already described, but one essential element of success in this 

 kind of leather lies in the perfect removal of all lime from the skins. 

 This is effected by plunging the well-washed skins in a bath of bran 

 or rye flour, which has been allowed to enter into a state of fermenta- 

 tion. The result is, that the lactic and acetic acids generated by 

 fermentation of the amylaceous substances combine with the lime and 

 remove it from the skins. The other essential point is the mode of 

 tanning the skins. Each skin is sown so as to form a bag, and filled, 

 through a small opening, with a strong decoction of sumach, and after 

 the aperture has been closed the skins are thrown into a large vat con- 

 taining also a decoction of the same material. After several hours they 

 are taken out, emptied, and the operation is repeated. To render these 

 skins ready for commerce it is necessary to wash, clean, and dye them. 

 The last operation was formerly tedious, and required great skill, but 

 since the introduction of tar colours, the affinity of which for animal 

 matters is so great, it has become comparatively easy. The skins, after 

 they have been dyed, are oiled, slightly coloured, and the peculiar 

 grain, characteristic of Morocco leather, is imparted to them by means 

 of grooved balls or rollers. There are two inferior kinds of Morocco 

 leather manufactured, viz., those called roan, prepared in a similar 

 way to Morocco, but not grained ; and skivers, also prepared in the 

 same manner, but from split sheep skins. 



Russia Leather. — The great esteem in which this leather is held is 

 owing to its extreme softness and strength, its impermeability, and 

 resistance to mildew, which latter property is imparted to it by the 

 use of a peculiar oil in its currying — that is, birch-tree oil — the odour of 



