380 Mr, Cavendish’s Experiments on Jir. 
It may be worth remarking, that whereas in the detonation 
of nitre with inflammable fu bilances, the acid unites to phlo- 
gijjott, and forms phlogifticated air, in thefe experiments the 
reverfe of this, procefs was carried on ;• namely, the phlogifti- 
cated air united to the dephlogifticatcd air, which is equivalent 
to being deprived of its phlogifton, and was reduced to nitrous 
. acid. 
In the above-mentioned Paper I alfo gave my reafons for 
thinking, that the fmall quantity of nitrous acid, produced by 
the explofion of dephlogifticatcd and inflammable air, pro- 
ceeded from a portion of phlogifticated air mixed with the de-' 
phlogifticated, which I fuppofed was deprived of its phlogifton, 
and turned into nitrous acid, by the adtion of the dephlogifti- 
cated air on it, aftifted by the heat of the explofion. This 
opinion, as muft appear to every one, is confirmed in a re- 
markable manner by the foregoing experiments ; as from them 
it is evident, that dephlogifticated air is able to deprive phlo- 
gifticated air of its phlogifton, and reduce it into acid, when 
aftifted by the eledtric fpark ; and therefore it is not extraordi- 
nary that it ihould do fo, when aftifted by the heat of the 
explofion. 
The fcap-lees ufed in the foregoing experiments were made 
from fait of tartar, prepared without nitre ; and wxre of fuch 
a ftrength as to yield one-tenth of their weight of nitre when 
faturated with nitrous acid. The dephlogifticated air alfo was 
prepared without nitre, that ufed in the firft experiment with 
the foap-lees being procured from the black powder formed by 
the agitation of quickfiiver mixed with lead*, and that ufed 
* This air was as pure as any that can be procured by moft procefles. 1 pro- 
pofe giving an account of the experiment, in which it was prepared, in a future 
Paper. 
in 
1 
