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being improbable that nitrous air may alfo produce 
the fame effeft by the fame means. 
To this hypothecs it may be obje&ed, that, if 
diminithed air be air faturated with phlogifton, it 
ought to be inflammable ; but this by no means 
follows, fince its inflammability may depend upon 
fome particular mode of combination, or degree of 
affinity, with which we are not acquainted. Befldes, 
inflammable air feems to confift of fome other prin- 
ciple, or to have fome other conftituent part, befldes 
phlogifton and common air, as is probable from that 
remarkable depoflt, which, as I have obferved, is 
made by inflammable air, both from i{on and zinc. 
It is not improbable, however, but that a greater 
degree of heat may inflame that air which ex- 
tinguilhes a common candle, if it could be conveni- 
ently applied. Air that is inflammable, I obferve, 
extinguifhes red hot wood ; and indeed inflammable 
fubftances can only be thofe which, in a certain de- 
gree of heat, have a lefs affinity with the phlogifton 
they contain, than the air, or fome other contiguous 
fubftance, has with it; fo that the phlogifton only 
quits one fubftance, with which it was before com- 
bined, and enters another, with which it may be 
combined in a very different manner. This fubftance, 
however, whether it be air or any thing elfe, being 
now fully faturated with phlogifton, and not being 
able to take any more, in the fame circumftances, 
muft neceffarily extinguifh fire, and put a flop to 
the ignition of all other bodies, that is, to the farther 
efcape of phlogifton from them. 
That plants reftore noxious air, by imbibing the 
phlogifton with which it is loaded, is very agreeable to 
Yql, LXII. H h the 
