CHAMOY LEATHER. 



VIII. 



mi 



Account of a Memoir on clmmoying of Leather. 

 By M. Seguin, * 



SEGUIN, who has already publldied feveral interefl- 



ing works on the arts, relating to the preparation of fkins, 



has lately, read to the Inftitute a firft memoir on chamoying, 



from which we fliall give an extra6l. 



The author ftates, that the art of chamoylng confifts in dif- Mechanical 

 ^ , A . • 1 •! • • ,• xi -.1 operations of 



pofing the Ikms to receive the oil ; m impregnating them with chamoying. 



it by different operations, of which he probably referves the 

 details for a fecond memoir ; in then canting them to undergo 

 a fpecies of fermentation; in expofing them to the air; and^ 

 laftly, in taking from them, by means of potafli, the excefs 

 of oil which is ufelefs to them. 



He afterwards palTes to the chemical examination of a cha- 

 moyed (kin. 



' He found that this fkin did not undergo any alteration by Chemical exa- 

 a long boiling in water; but that, if any acid wTiatever i'"* ^'"y'.^^J^^^^^ 

 added (M. Seguin made ufe of fulphuric acid), the fldn dif- 

 appeared entirely ; that a certain quantity of a concrete oil 

 fwam on. the furface of the liquid ; that the liquor contained 

 gelatine; and that, by its evaporation, it depofited cryftals 

 of fulphate of potath. He alfo afcertained, that on pouring Gelatine poure4 

 gelatine into a foiution of foap, an infoluble precipitate is ob- X^^^ilxllV^ 

 tained, which, treated with an acid, comports itfelf exa6lly precipitate which 

 like a chamoyed (kin. refembles a cha- 



r^. /- /, . . /• 1 ,• , 1 • 1 .1 r moved fkin in 



Thefe refults, and the confiderations to which the expofi- jtj chemical pro- 



tion of the principal operations of chamoying have given rife, perties. 

 induced M. Seguin to conclude that the Ikins, in the fermen- Theory of the 

 tation which they undergo, yield a part of their oxigen to the °P^"'^'°°* 

 oil; that the potafli employed to cleanfe them, forms a foap 

 with the oxigenated oil ; that one part of this foap, by com- 

 bining with the difoxigenated tkin, produces the infoluble 

 fubitance which makes the (kin chamoyed; and, that the other 

 part ferves to conftitiite that greafe which remains in the 

 leather. 



* From Bulletin des Sciencef, Tom. III. p. 20^. 



This 



