78 Memoir upon Animal Fat. 
I made this experiment in a retort in the pheumatic ap? 
paratus, and I obtained azotic gas as the produce: this gas 
was not disengaged pure, as M. Alyon announced ; it was 
mixed with nitrous gas and carbonic acid gasy as justly 
observed by M. Van Mons. 
Fat thus oxygenated, of a hardness equal to suet; melts at 
the temperature of 36° or 38° of Reaumur, (96° to 100° of 
Fahr.) 
I boiled it with water, which acquired a citron yellow co- 
lour from it, had a bitter and sharp taste, reddened turnsole 
paper, and constantly precipitated the acetate of lead and 
nitrate of mercury. This water distilled in a retort, almost 
to dryness, yields a colourless white liquor which contains 
a quantity of acetic acid; it does not then precipitate the 
above metallic solutions. 
The washings of fat, evaporated to the consistence of a 
thick liquid, deposit, upon cooling, a tenacious brown sub- 
stance, which attracts humidity from the air. .The liquor 
being decanted and exposed to evaporation in a stuve, am 
infinity of very brilliant white needles crystallize in it. I 
took these crystals at first for oxalic acid; but lime-water 
was not in the least affected by them ; besides, they had no 
other of the properties of the oxalic acid: we shall see their 
nature a little further on. 
However often we may wash oxygenated fat, its yellow 
colour and its acidity never leave it. After the twelfth boil- 
ing it is still yellow, and the water coming from it reddens 
turnsole. 
Alcohol acts differently : on boiling it with oxygenated 
pomatum, it dissolves a very great quantity of it; upon 
eooling, plenty of flakes are separated from it, which, being 
collected and dried, yield an oxygenated fat which is singu- 
larly bleached. The fat remaining is also whiter ; the al- 
cohol acquires a yellow colour, and becomes acid: it ree 
tains enough of matter in solution, to be abundantly preci« 
pitated by water. 
I evaporated this alcohol; plenty of yellow acid fat re~ 
mained ; water effected its solution in part. 
Boiling alcohol, frequently employed to wash oxygenated 
fat, 
