s 
on Hepatic Air \ 123 
with fulphur, that it depofited fome in the tube through 
which it was tranfmitted, and on the upper part of the glafs 
receiver. This air I transferred to another receiver; but 
though it was then perfe&ly clear and tranfparent, and amounted 
to 6 cubic inches, yet the next morning the infide of the glafs 
w r as thickly lined with fulphur, and the air reduced to 1 cubic 
inch, which was pure vitriolic air. Hence it appears, firft, that a 
fpecies of elaftic fluid may exift in a ftate intermediate between 
the aerial and the vaporous, which is not permanently elaftic 
like air, nor immediately condenfed by cold like vapour, but 
which, by the gradual lofs of its fpecific heat, may be reduced 
to a concrete form. 2dly, That fo large a quantity of ful- 
phur may be combined with vitriolic air, as to enable it to ex- 
hibit the properties of hepatic air, for fome time at leaft. A 
mixture of three parts pulverifed quick-lime and one part ful- 
phur, heated to whitenefs in a covered crucible for one hour, 
became of a ftony hardnefs, and being treated with marine 
acid, afforded hepatic air. If a piece of this ftone be heated 
in pure water it becomes bluifh, and hence the origin of the 
blue marles generally found near hot fulphurated waters. 
A calcareous hepar may alfo be formed in the moift way, as 
is well known. 
Magnejia free from fixed air, heated in the fame manner 
with fulphur, afforded no hepatic air when an acid was poured 
on it. 
I alfo procured this air from a mixture of three parts filings of 
iron and one of fulphur, melted together, and treated with 
marine acid. It is remarkable, that this fulphurated iron, dif- 
folved in marine acid, affords fcarce any inflammable, but 
moftly hepatic air* 
R 2 
A mixture 
