t/6 Anahfis of the Air , 
And the effed the half cxhaufting of a 
receiver has upon the elafticity of the re- 
maining half of the air, feems to be the rea- 
fon why the flame of a Candle does not 
continue burning, till it has filled the recei- 
ver it Hands in with fumes, but goes out 
the quicker, the fooner the air is drawn out 
to that degree 5 which feems therefore to be 
owing to this, that an air rarified to double 
its fpace, will not expand fo briskly with 
the warmth of flame, as a more condenfed 
air will do : And confequently adion and 
re-adion being reciprocal, will not give fo 
brisk a motion to the flame, which fubfifts 
by a conftant fuccelllon of frefh air, to fup- 
ply the place of the either abforbed, or much 
dilated air, which is continually flying off. 
And the quicker the fucceffion of this frefh 
air is, by blowing, the more vigoroully does 
a fire burn. 
If the continuance of the burning of the 
Candle be wholly owing to the vivifying 
fpirit y then fuppofing in the cafe of a recei- 
ver, capacious enough for a Candle to burn 
a minute in it, that half the vivifying fpirit 
be drawn out with half the air; in ten fe- 
conds of time ; then the Candle fhould not 
go out at the end of thofe 10 feconds, but 
4 burn 
