Decompaction of dephlogiflicated and inflammable Air. 2 \ 9 
after either of our procefles, any furplus of either of the two 
kinds of air would only have remained unfaturated, and have 
been found unchanged in the refiduum. 
1 claim no merit whatever in this obfervation. It was in 
confequence of accidentally finding pure water in what I then 
imagined to be the fame circumftances in which I had always 
before found acid, and which furprized me not a little at the 
time, that I was led to vary the proportions of the two kinds 
of air, till at length I fucceeded in afcertaining the circum- 
ftances on which this remarkable difference in the refult de- 
pends ; but I am by no means able to aftign any reafon for this 
difference. 
In this ftate of my experiments I concluded, that nitrous 
acid, though confifting of the fame elements with pure water, 
contains a greater proportion of dephlogifticated air; and in 
the laft edition of my Obfervations on Air, Vol. III. p. ^43. I 
obferved, that fubftances, poflelled of very different proper- 
“ ties > ma y be compofed of the fame elements, in different pro- 
“ portions, and different modes of combination. It cannot 
“ therefore be faid to be abfolutely impoflible, but that water 
“ may be compofed of thefe elements,” viz. dephlogifticated 
and inflammable air. 
, ' r ■ 
When J fir ft prepared an account of my late experiments 
for the Royal Society, I entertained this idea ; but I now con- 
fider it as at leaft uncertain, becaufe when I mix the two kinds 
of air in fuch proportions as to produce water , I find in the 
refiduum much more phlogiflicated air than I do when acid is 
produced, which affords a fufpicion that, in this cafe, the prin- 
ciple of acidity goes wholly into the phlogiflicated air, which, 
as my former experiments (hew, actually contains it, though 
it is not eafy to afcertain in what proportion. 
G g 2 
Having 
