Mr. Caven DISH’s Experiments o on i Air: - 137 
‘none then 3 remains to deprive the a eas air 5 its phio- 
Bifton, and turn itinto acid. oe ene 
If the latter explanation be true, T hie we mutt allow 
‘that dephlogifticated air is in reality nothing but dephlopifti- 
cated water, or water deprived of its phlogifton ; or; in’ other 
~Svords, that water confifts of dephlogifticated air* united to 
phlogifton ; and that inflammable air is either pure phlogifton, 
‘as Dr. PkirstLey and Mr. Kirwan fuppofe, or elfe water 
united to phlogifton*; fince, according to this fappofition, 
thefe two fubftances united together form pure water. On the 
‘other hand, if the firft explanation be true, we muft fappofe 
that dephlogifticated air confifts of water ‘united to ‘a’ little 
‘nitrous acid and deprived of its phlogifton; but ftill the ni- 
trous acid in it muft make only a very {mall part of the whole, 
* Hither of thefe fuppofitions will agtee equally well with the following expe- 
iments} but the latter féems to me much the moftlikely. What’ principally 
makes me think fo is, that commoa or dephlogifticated air do not abforb phlo- 
gifton from inflammable air, | uinlefs aflifted by a red heat, whereas they abforb 
the phlogifton of nitrous air, liver of fulphur, and many other fubftances, with- 
out that affiftance ; and it feems inexplicable, that they-fhould refufe to unite to 
‘pure phlogiftos, when they are able to extract it from fubftances to which it has an 
affinity ; that is, that they fhould overcome the affinity of phlogifton to other 
fubftances, and extrac& it from them, when they will not even unite to it when 
prefented to them, On the other hand, I know no experiment which fhews 
inflammable air to be pure phlogifton rather than an union of it with water, 
unlefs it be Dr. Prizsriey’s éxperiment of expelling inflammable air from iron 
by heat alone. 1 am not fufficiently acquainted with the circumftahces of that 
experiment to argue with certainty about it; but I think it much more’likely, 
that the inflammable air was formed by the union of the phiogifton of the iron 
filings with the water difperfed among them, or contained i in the retort or other 
vetfe! in which it was heated; and in all probability this was the caufe of the 
Aeparation of the phlogifton, as iroh feems not difpofed to part with its phlo- 
gifton by heat alone, without being affifted by the air of fome other fubftance. 
Vor. LXXIV, g2 as 
