278 APPENDIX. 
in thefe Bubbles is not forcibly pent up in 
them, as I found by the following Experiment, 
viz. having placed a Piece of Ice under Wa- 
ter, I pierced Holes into fevcral of the Bubbles^ 
yet the Air did not rufli out with any Force, 
which it would have done, if it had been in 
a ftrongly expanfive State. 
9. But tho* a good part of the Air, which 
thus arifes from Fluids, (eems to have exifted 
in an elaftic State in thofe Fluids 5 yet the Air 
which arifes from folid Bodies either by the 
Force of Fire, or of Etfervefcence, does not 
feem to arife only from the Interftices of thofe 
Bodies, but principally from the moft fixed 
Parts of them. For fince the Airs which are 
raifed by the fame acid Spirit from a great Va- 
riety of Siibftances have very different Degrees 
of Permanency, as it was found in Experiment 
X. Numb. 5, 4, 5, 6, (^c. and in Experiment 
XL Numb. 6 y 7, 8, 5>, 10. of Experiments 
on Stones 5 hence f is probable that thefe Airs 
do not arife from latent Interftices of the dif- 
folved Stones, e^c. but from the folid fixed 
Subftance of them. And fince the whole of 
fome of thefe new generated Airs, does in a 
few Days lofe its Elafticity, it fhould feem 
hence probable that whatever Air arifes from 
6 , the 
