212 Analyfis of the Air. 
great preflure of the incumbent water, but 
alfo by its coldnefs at great depths 5 and in 
/hat proportion, at different known depths* 
and in different lengths of time, that an al- 
lowance may accordingly be made for it at 
unfathomable depths. 
This gage will alfo readily fhew the de- 
grees of compreffion in the condenfing en- 
gine. 
But to return to the fubje&of the two laft 
Experiments, which prove the elafticity of 
this new generated air 5 which elafticity is 
fuppofcd to confift in the aCtive aerial par- 
ticles, repelling each other with a force, 
which is reciprocally proportional to their 
diftances. That illuftrious Philofopher, Sir 
Ifaac Newton , in accounting how air and 
vapour is produced, Opticks ^uer. 31. fays, 
<c The particles when they are fhaken off 
from bodies by heat or fermentation fo 
“ foon as they are beyond the reach of the 
<£ attraction of the body receding from it, 
<c as alfo from one another, with great 
“ ftrength and keeping at a diftance, fo as 
fometimes to take up above a million of 
u times more fpace than they did before in 
u the form of a denfe body, which vaft:^ 
a contraction and expanfion feemsunintel- 
“ ligible. 
