160 
Spent Oil of the Curriers * 
INTELLIGENCE, 
Sficnt Oil of the Cwriers.* 
The process by which the curriers impregnate their skins is by 
smearing the oil upon the wet skin, into which it penetrates as the 
moisture evaporates. A pure oil could not perhaps be thus spread, 
and most probably would not enter the skin with the desired effect, 
or render it as supple as that oil which from experience they are 
led to prefer. 
The celebrated Seguin has directed his attention to this ingre- 
dient of such extensive manufacturing utility. He remarks, that 
this material (by the name of Degras) is of two kinds in France; 
viz. the common sort and that of Niort. The first is the imme- 
diate product of the chamoying of skins, which are cleared of their 
surplus oil by solution of potash. It therefore contains not only 
soap, but likewise gelatine. It is evaporated to dryness, and then 
sold as Degras. At Niort it is decomposed by sulphuric acid, and 
the precipitate is called the Degras of that town. 
Mr. Seguin finds by analysis, that this last is oxigenated oil, 
whereas the other is a compound of soap and gelatine. He suc- 
ceeded in giving to whale oil all the properties of the Degras of 
Niort, by boiling one pound for a few minutes with half an ounce 
of nitric acid at 25 degrees. He observed that no gas is disen- 
gaged in this operation ; but that water and nitrate of ammonia are 
formed ; and he concludes that the oil was oxigenated, not by ab- 
sorbing the oxigen of the acid, but by yielding to it part of the hy- 
drogen which was one of its own component parts. The result is 
the more interesting, as the Degras of Niort being much more 
esteemed than the common sort, the curriers may hereafter, instead 
of paying a great price for it, make it in as large quantities as they 
please by following the process here indicated. 
Nich. Ph, Mag, vol. 12. p. 220. 
