20 t Analyfis of the Atr. 
by means of fire ; we fhall find in the fol- 
lowing Experiments many inftances of the 
production ; and alfo of the fixing or ab- 
sorbing of great quantities of air by the fer- 
mentation arifing from the mixture of va- 
riety of folids and fluids : Which method 
of producing and of abforbing, and fixing 
the elaftick particles of air by fermentation, 
feems to be more according to nature’s 
ufual way of proceeding, than the other 
of fire. 
Experiment LXXX. 
I put into the bolthead b (Fig. 34.) 16 cu- 
bick inches of Sheeps biood, with a little 
water to make it ferment the better. I 
found by the defcent of the water from ss 
to y that in 1 8 days fourteen cubick inches 
of air were generated. 
Experiment LXXXI. 
Volatile Salt of Sal Ammoniac, placed in 
an open glafs ciftern, under the inverted 
glafs z z a a, (Fig. 35.) neither generated 
nor abforbcd air. Neither did feveral c- 
thcr volatile liquors, as fpirits of Harts- 
horn, fpirits of Wine, nor compound A- 
quafortis, generate any air. But Sal Am- 
moniac, 
