^o5 ' D/*. Crawford’s Experiments on the Matter 
air, nor immediately condenfed by cold like vapour, but gra- 
dually affuming the non-elaftic foim, in confequence probably 
of the tendency ot its feveral parts to unite witn eacn o^her. 
The air produced in the foregoing experiment rendered lime- 
water turbid ; it therefore contained a quantity of fixed air; 
and towards the end of the diftillation a little volatile alkaline 
air came over, agreeably to the obfervation of M. Berthollet . 
for, when a portion of the air received during this part of the 
procefs was mixed with an equal quantity of marine acid air, a 
white vapour was produced, and a diminution of about one 
twenty-fifth of the whole took place, 
I endeavoured, by the following experiment, to afcertain the 
proportion of fixed air contained in the aerial fluid which is dn- 
enp-aged from the lean of animal fubftances by heat. 
A quantity of air, extricated from the lean of frefh mutton, 
was received over mercury in a large phial which had a narrow 
neck. When the phial was a little more than half filled, the 
remaining portion of the mercury was difplaced by introducing 
water that had been previoufly boiled. The phial being then 
clofely corked, the air and water were brilkly agitated together ; 
and the liquor, thus impregnated with the foluble part of the 
animal air, was put into a proof, to the bottom of which heat 
was applied. By this means a portion of the air was again difen- 
eaged* which was received in a tube inverted over mercury. The 
procefs was continued till the liquor in the proof no longer ren- 
dered lime-water turbid. As the air received in the tube contained 
the fixed air that had been extricated from the liquor, together 
with a quantity of common air expelled from the proof, it was a 
fecond time agitated with water ; and the exaff meafure o t e 
fixed air was known by the portion which the water imbibed. 
The fixed air, thus ascertained, being compared with the entire 
■quantity of air that had been originally abforbed, it appeared 
