2p4 Analyjts of the Air. 
Thus in Experiment 73 we fee by the vaft 
quantity of air there is found in Tartar, 
that tho’ it contains the other principles of 
vegetables, yet air with fome volatile Salt 
feems to make up a confiderable part of its 
compofition , which air, when by the aftion 
of fire it is more firmly united with the 
earth, and acid fulphureous particles, requires 
a more intenfe degree of heat, to extricate, 
it from thofe adhering fubftances, as we find 
in' the diftillation of Sal Tartar, Exper. 74* 
which Air and volatile Salt are moft; readily 
feparated by fermentation. 
And by Experiment 72, plenty of air arifes 
alfo from Nitre, at the fame time that the 
acid fpirit is feparated from it by the action 
of fire. 
We find alfo by Experiment 71, that 
fome air is by the fame means obtained 
from common fea Salt, tho' not in fo great 
plenty, nor fo eafily, as from Tartar and Ni' 
tre, it being a more fixt body, by reafon of 
the fulphur which abounds in it ; neither 
is it fo cafily charged in animal bodies, as 
other Salts are, yet lince it fertilizes ground, 
it mult needs be changed by vegetables. 
There 
