[ 180 ] 
Inflammable air thus diminifhed by agitation in 
water, makes but one explofion on the approach of 
a candle exa&ly like a mixture of inflammable air 
With common air. 
From this experiment I concluded that, by con- 
tinuing the fame procefs, I fhould deprive inflam- 
mable air of all its inflammability, and this I found 
to be the cafe ; for, after a longer agitation, it ad- 
mitted a candle to burn in it, like common air, only 
more faintly 5 and indeed by the teft of nitrous air 
it did not appear to be near fo good as common air. 
Continuing the fame procefs ft ill farther, the air 
which had been moft ftrongly inflammable a little 
before, came to extinguish a candle, exactly like air. 
in which a candle had burned out, nor could they 
be diftinguifhed by the teft of nitrous air. 
I found, by repeated trials, that it was difficult to 
catch the time in which inflammable air obtained 
from metals, in coming to extinguirh flame, was in 
the ftate of common air, fo that the tranfition from 
the one to the other muft be very fhort. I readily,, 
however, found this ftate in a quantity of inflam- 
mable air extracted from oak, which air I had kept 
by me a year, and in which a plant had grown, 
though very poorly, for fome part of the time. A 
quantity of this air, after being agitated in water till, 
it was diminished about one half, admitted a candle 
to burn in it exceedingly well, and was even hardly 
to be diftinguifhed from common air by the teft of 
nitrous air. 
I took fome pains to afcertain the quantity of di- 
minution, in frefh made and very highly inflam- 
mable air from iron,, at which it ceafed to be inflam- 
usable* 
