2 10 Arialyfis of the Air. 
We may make a like eftimatc alfo, ftom 
the great quantities of air which arofc 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 Oaky 
Z16 times its bulk of air. Now 216 cubick 
inches of air, comprefTcd into the fpace of 
one cubick inch, would, if it continued there 
in an elaftick ftatc, 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 5 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 meft 
of thefe now a£!Uve 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 aGive repelling ftate by fermen- 
tation and fire. 
The weight of a cubick inch of Apple 
being 19 1 grains, the weight of a cubick 
inch of air f of a grain, 4-8 times that weight 
of air is nearly equal to the fourteenth part 
of the weight of the Apple. 
And 
