no Analyfis of the Air. 



We may make a like eftimate alfo, from 

 the great quantities of air which arofe ei- 

 ther by fermentation, or the force of fire 

 from feveral other bodies. Thus in Exp. 55. 

 there arofe from a piece of heart of Oak, 

 216 times its bulk of air. Now 216 cubick 

 inches of air, comprefled into the fpace of 

 one cubick inch, would, if it continued there 

 in an elaftick ftate, prefs againft one fide of 

 the cubick inch, with an expanfive force 

 equal to 3310 pounds weight, fuppofing 

 there were no other fubftance but air con- 

 tained in it $ and it would prefs againft the 

 fix fides of the cube, with a force equal to 

 19860 pounds, a force fufficient to rend 

 the Oak with a vaft explofion : 'tis very 

 reafonable therefore to conclude, that moft 

 of thefe now active particles of the new 

 generated air, were in a fix'd ftate in the Ap- 

 ple and Oak before they were roufed, and 

 put into an aftive repelling ftate by fermen- 

 tation and fire. 



The weight of a cubick inch of Apple 

 being 1 9 1 grains, the weight of a cubick 

 inch of air f of a grain, 48 times that weight 

 of air is nearly equal to the fourteenth part 

 of the weight of the Apple* 



And 



