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being improbable that nitrous air may alfo produce 

 the fame effect by the fame means. 



To this hypothecs it may be objected, that, if 

 diminifhed air be air faturated with phlogifton, it 

 ought to be inflammable ; but this by no means 

 follows, iince its inflammability may depend upon 

 fome particular mode of combination, or degree of 

 affinity, with which we are not acquainted, Belides, 

 inflammable air feems to confift of fome other prin- 

 ciple, or to have fome other confdtuent part, befldes 

 phlogifton and common air, as is probable from that 

 remarkable depofit, which ? as I have obferved, is 

 made by inflammable air, both from iron and zinc. 



It is not improbable, however, but that a greater 

 degree of heat may inflame that air which ex- 

 tinguiihes a common candle, if it could be conveni- 

 ently applied. Air that is inflammable, I obferve, 

 extinguishes red hot wood j 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 neceflarily extinguish 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 



Vol. LXII, H h the 



