124 iWK Kirwan’s Experiments 
A mixture of equal parts filings of iron and fulphur, 
made into a pafte with water, after heating and becoming 
black, afforded hepatic air when an acid was poured on it; but 
this hepatic air was mixed with inflammable air, which pro- 
bably proceeded from the uncombined iron. After a few days, 
this pafte loft its power of producing hepatic air. 
M. Bergman has remarked, that combinations of fulphur 
with fome other metals yield hepatic air. 
I attempted extracting air from a mixture of oil of olives with 
cauftic vegetable alkali. It immediately whitened, and on ap- 
plying heat effervefced fo violently as to pafs over into the 
receiver : nor had I better fuccefs on adding an acid, as I might 
well forefee. The event was different when on a few grains of 
fulphur I poured fome of the oil, and heated them in a phial 
with a bent tube ; for as foon as the fulphur melted, the oil 
began to a dc on it, grew red, and emitted hepatic air, fimilar 
to that produced by other proceffes. 
I alfo obtained this air in great plenty from a mixture of equal 
parts fulphur and pulverifed charcoal , out of which its adventi- 
tious air had been as much as poflible expelled by keeping it a 
long time heated to rednefs, in a crucible on which a cover 
was luted, with a fmall perforation to permit the air to efcape. 
This air was inflammable, as appeared by holding a lighted 
candle before it during its emiffion; yet it is hardly poflible to 
free charcoal wholly from foreign air, for it foon re-attra£ls it 
when expofed to the atmofphere. 
This laft mixture, when diftilled, affording a large quantity 
of hepatic and fome inflammable air, without the addition of 
any acid, I imagined, that as the retort was only half full, it 
might contain a fofficiency of atmofpheric air to admit the 
eombuftion of part of the fulphur, and thus furnifh the necef- 
