the heavy inflammable Air, 67 
Experiment. Inflammable air, from which hepatic air had 
been made, and had been feparated by expo fu re to water, 4!, 
and dephlogifticated air 6f, were inflamed in a large exploding 
jar. After the inflammation they meafured 6 ; and after being 
agitated with lime water 2}. This refidue burnt with increafed 
Q 
flame. 
The airs ufed in this experiment were the farrie as thofe in 
the fecond experiment. The quantity of fixed air generated is 
only 0,035 lefs in proportion than was produced in the third 
experiment from the air in its original ftate. 
The refidue is only 0,17 more than it fhould be by calcula- 
tion, allowing the dephlogifticated and inflammable airs to 
enter into fixed air in the proportion of feven to five. 
The remaining heavy inflammable air is therefore very little 
altered as to its quality by this operation, though it is much 
lefs in quantity than can be accounted for from the production 
of hepatic air. For the light inflammable air in the conftitu- 
tion of hepatic air is expanded to the fame degree as in its 
Ample ftate ; and an expanfion might be expeCted, when the 
hepatic air is generated from the heavy inflammable, juft as 
when the lighter air is feparated from the heavy by the electrical 
fhock ; but no expanfion is obferved in this inftance. I there- 
fore fufpeCt, that, when hepatic air is formed in the heavy 
inflammable air, the heavy air is imperfectly decompofed ; that 
only a part of the light inflammable air is combined with ful- 
phur ; and that the remaining parts are precipitated in a ftate 
analogous to charcoal, and blacken the fulphur. Upon apply- 
ing heat to the fulphur thus blackened, I have perceived an 
hepatic fmell. This blackened fulphur is not entirely diffolved, 
like pure fulphur, by being boiled in cauftic alkali, but a black 
powder remains. In one inftance, this black fubftance difap- 
K 2 peared 
