2^4 Analyfis of the Aif. 



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 5 which air, when by the action 



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 moll 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 aclion 

 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 5 neither 

 is it fo eafily charged in animal bodies, as 

 other Salts are, yet fince it fertilizes ground, 

 it mull: needs be changed by vegetables. 



There 



