THE TECHNOLOGIST. [Nov. 1, 1864. 



156 ON CHEMISTRY APPLIED TO THE ARTS. 



are then softened by working tnem with, a peculiar iron tool, the whit« 

 surface which characterises that class of leather being communicated 

 to them by stretching them on a frame and rubbing them with pumice- 

 stone. A large quantity of jtawed leathers are also preserved retaining 

 their hair, which is done by simply suppressing the uuhairing and 

 rubbing processes. 



Chamois, Wash, or Oiled Leather. — These classes of leather are named 

 from the fact that formerly they were exclusively produced from the 

 skin of the chamois ; but at the present day, sheep, calf, and deer 

 skins, and even split thin hides, are manufactured into oiled leather. 

 The employment of this kind of leather has greatly decreased of late 

 years, owing to the general substitution of woollen fabrics in articles of 

 clothing. The preparation of this class of leather differs entirely from 

 those previously detailed ; the conversion of skins into leather, or from 

 a substance subject to putrefaction to one free from that liability, being 

 no longer effected by tannin, as in the case of hides and Morocco and 

 Eussia leathers, or by the use of mineral salts, as in tawed leathers, but 

 by that of fatty matters, especially animal oils, such as sperm. The 

 skins are prepared in the same manner as for tawed leathers, and then 

 submitted to what is called the prizing operation, which consists in 

 rubbing the hair side of the skin with pumice-stone or a blunt tool or 

 knife, until the whole of the rough appearance is removed, and the skin 

 has acquired a uniform thickness. They are then worked on the peg 

 until the great excess of moisture has been wrung out, and plunged into 

 the trough of a fulling mill, to the action of the wooden hammers of 

 which they are subjected until nearly dry. They are then placed on a 

 table and oiled, and several of them, after being rolled together, are 

 replaced in the trough of the fulling mill. When the oil has been thus 

 worked into the substance of the skins, they are removed, exposed to the 

 atmosphere, again oiled, and once more subjected to the fulling mill, 

 after which they are placed in a moderately heated room for a day or 

 two, the object of which is twofold — viz., to facilitate the evaporation of 

 the water and the penetration of the oil, and to create a slight fermenta- 

 tion, by which the composition of certain of the organic substances have 

 undergone such modification as to enable them to combine in a perfect 

 manner with the fatty matters. These processes are repeated until the 

 manufacturer deems the leather sufficiently prepared to be fit to undergo 

 the following operations — viz., to be immersed for several hours in a 

 caustic lye bath, to remove the excess of oily matter, washed, and 

 pegged. It is only necessary to stretch the leather on a table, then on a 

 horse, and lastly between rollers, after which it is ready for the market. 

 The ordinary buff colour of these leathers is communicated by dipping 

 them, previously to the finishing processes, into a weak solution of 

 sumach. Before speaking of the further processes necessary to fit these 

 leathers for the glove manufacturer, I may describe that of Mr. C. A. 

 Preller, whose mode of preparing leather is very interesting, owing to 



