on Water and Dephlogiflicated Air. pay, 
than litmus is; but which turns green in the fame folution of 
phlogifticated nitre that turns litmus red. 
_ ‘The unavoidable little accidents which have attended thefe 
experiments, and which tend to render their refults dubious,. 
have prevented me from relying on them as full proofs of the. 
pofition that no acid enters into the compofition of dephlogifti- 
cated air; though they give great probability to the fuppofi- 
tion. Ihave, therefore, explained the whole of the hypothefis 
and experiments with the diffidence which ought to accompany 
every attempt to account for the phenomena of nature on 
other principles than thofe which are commonly received by 
philofophers in general. And in purfuance of the fame mo- 
tives it is proper to mention, that the alkali employed to fatu- 
rate the phlogifticated nitrous acid, was always that of tartar 
which is partly mild; and I have not examined whether highly 
phlogifticated nitrous acid can perfectly expel fixed air from an 
alkah, though I know no fact which proves the contrary. It 
fhould alfo be examined, whether the fame quantity of real 
nitrous acid is requifite to faturate a given quantity of alkali, 
when the acid is phlogifticated, as is neceflary when it is de+ 
phlogifticated. 
As I am informed that you-have done me the honour to com+ 
municate my former letter on this fubject to the Royal Society, 
I thall’be obliged to you to do me the fame favour in refpect te. 
he oe letter, if you judge that it merits it.. 
Tremain, &c. 
JAMES WATT. 
