of Cancer , and on Animal Hepatic Air . 4 r 5 
whether vitriolic acid be produced by the combuftion of he- 
patic with atmofpherical air. One meafure of hepatic air, 
obtained from artificial pyrites, was mixed over mercury with 
aoout fix me a fu res of atmofpherical air, and fired by the elec- 
tric (hock. A copious precipitation of fulphur took place, the 
remaining air was then agitated with diftilled water, the latter 
was filtered, and muriated barytes was added, which pro- 
duced a white precipitate not diffoluble in a large quantity of 
water. 
From this, and the foregoing experiment, it appears, that 
when fulphureous hepatic is burned with atmofpherical air, a 
part of the fulphur is changed into vitriolic acid, and the reft 
is precipitated ; but when it is burned with a fufficient quan- 
tity of pure air, the fulphur is wholly converted into vitriolic 
acid. Agreeably to this conclufion, I have found that the 
odour of the volatile vitriolic acid conftantly accompanies the 
combuftion of hepatic with common air in open veflels; and 
that when concentrated nitrous acid is added to water impreg- 
nated with hepatic air, the filtered liquor becomes turbid upon 
the addition of muriated barytes. 
The quantity of pure air required to faturate fulphureous 
hepatic air, does not appear to correfpond with the fuppofition 
that the laft of thefe fluids confifts of fulphur diflolved in 
light inflammable air l for fulphur, in order to its complete 
faturation, requires only 1*43 times its weight of pure air; 
but light inflammable air requires for its faturation at leaft fix 
times its weight of that fluid. The fpecific gravity of hepatic 
air, as determined by Mr. Kirwan, is nearly equal to that of 
pure air. If, therefore, one-fixth of the weight of hepatic 
confifted of light inflammable air, that fluid would require for 
its faturation 2,26 times its bulk of pure air; for the portion 
of 
