Mr. CAVENDISH’Ss Experiments on Air. IA} 
both becaufe L:think it more likely that: there isino fueh thing 
as elementary heat, and becaufe faying {fo in this inftance, 
without ufing fimilar expreflions i in {peaking ‘of other chemical 
unions, would be improper, and would lead to falfe ideas; and 
it may even admit of doubt, whether the doing it in general 
would not caufe more trouble and perplexity than it is worth. 
‘There is the utmoift reafon to think, that dephlogifticated and 
phlogifticated-air, as M. Lavoisier and ScHEELE fuppofe, are 
quite diftin&. fubf{tances, and not differing only in their degrée,of 
phlogiftication ; and that common air is a mixture of the two; 
for if the dephlogifticated air is pretty pure, almoft the whole 
of it lofes its elafticity: by: phi ogiftication, and, as appears: by 
the foregoing experiments, is turned into water, inftead of 
being converted into phlogifticated air.. In moft of the fore- 
going experiments, at leaft +¢ths of the whole was turned into 
water; and by treating fome dephlogifticated air with liver of — 
fulphur, I have reduced it to lefs than 7,th of its original bulk, 
and other perfons, I believe, have reduced it to a full lefs bulk; 
fo that there feems the utmoft reafon to fuppofe, that the fmall 
refiduum which remains after its phlogiftication proceeds only 
from the impurities mixed with it. . 
It was juft faid, that fome dephlogifticated air was tedpedl by 
liver of fulphur to ,.th of its original bulk; the ftandard of 
this air was 4,8, and confequently the ftandard of perfetly 
pure dephlogifticated air fhould be very nearly 5, which is a 
confirmation of the foregoing opinion; for if the ftandard of 
pure dephlogifticated air is 5, common air muft, according to 
this opinion, contain one-fifth of it, and therefore ought to lofe 
one-fifth of its bulk by oo which is what itis, 
oo? found to lofe. 
Hiore 
