3 ‘ 8 Mr . Cavendish’s Experiments on Air . 
gift IC ated ; and therefore I tried whether nitre, much phlogifti- 
cated, would precipitate fiver from its folution. For this pur- 
pofe I expofed fome nitre to the fire, in an earthen retort, till it 
had yielded a gooc^ deal of dephlogifticated air ; and then, hav- 
ing diflblved it in water, and added to it iome well purified 
fpirit of nitre till it was fenfibly acid, in order to be certain 
that the alkali did not predominate, I dropped into it fom® 
folution of lilver, which immediately made a very copious pre- 
cipitate. This folution, however, being deprived of fome of 
its phlogifton by evaporation to drynefs, and expofure for a few 
weeks to the air, loft the property of precipitating filver from 
its folution ; a proof that this property depended only on its 
phlogiftication, and not on its having abforbed fea-falt from 
the retort, or by any other means. 
Hence it is certain, that nitre, when much phlogifticated, is. 
capable of making a precipitate with a folution of filver; and 
therefore there is no reafon to think, that the precipitate, 
which our fait occafioned with a folution of filver, proceeded 
from any other caufe than that of its being phlogifticated ; 
efpecially as it appeared by the fmell, both on firft taking it 
out of the tube, and on the addition of the fpirit of nitre, 
previous to dropping in the folution of filver, that the acid in 
it was much phlogifticated. This property of phlogifticated 
nitre is worth the attention of chemifts ; as otherwife they may 
fometimes be led into miftakes, in inveftigating the prefence of 
marine acid by a folution of filver. 
In the above-mentioned Paper I faid, that when nitre is deto- 
nated with charcoal, the acid is converted into phlogifticated 
air 5 that is, into a fubftance which, as far as I could perceive, 
pofifefies all the properties of the phlogifticated air of our at- 
mofphere ; from which I concluded, that phlogifticated air is 
5 nothing 
i 
