Mr. Kirwan’s Experiments , &c. i.i<^ 
fiances in the fame manner. M. Viellard has lately difca- 
vered feverai other indications of this air in putrefied blood. 
Yet, deferving as this fubftance appears to be of a thorough 
inveftigation, it has as yet been very little attended to. The 
experiments of M. Bergman have not been fufficiently nu- 
merous, and thereby led him into fome miftakes. Dr. Priest let 
has intirely overlooked it. The refearches of the ingenious M. 
Sennebier, of Geneva, have indeed been very extenfive ; 
but as,, for particular reafons, he operated on this air over 
water (by which it is in great meafure abforbed) inftead of 
quickfilver, his conclufions appear in many refpefts objec- 
tionable, as will be feen in the fequel. The experiments I have 
now the honour of laying before the Society were all made 
over quickfilver, and feverai times repeated,. 
» 
SECTION E. 
Of the Subjlances that yield Hepatic Air, and the means of 
obtaining it* 
It is well known, that f aline liver of fulphur is formed, in 
the dry way, of a mixture of equal parts of vegetable or mi- 
neral alkali and flowers of fulphur, melted together by a mo- 
derate heat, in a covered crucible. I examined the circum- 
fiances of its formation, and obferved,, that when, this mixture 
was (lightly heated, it emitted a bluifli fmoke, which gra- 
dually grew whiter as the heat was increafed, and at laft, when 
the mixture was perfectly melted, and' the bottom of the cru- 
cible (lightly red, became perfectly white and inflammable. 
To examine the nature of this fmoke, I made a pretty pure 
fixed alkali, by deflagrating equal parts of cream of tartar and 
nitre 
