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Experiment III. 
In order to afcertain the quantity of air contained 
in the Pouhon water, a Frontiniac vial was there- 
with filled at the fountain, on a clear morning, when 
the wind was eaflerly, and a flrong fwine’s bladder, 
well freed from air, was immediately fitted thereto ; 
all the air was then carefully expelled from this water 
by the heat of the bath, after the manner related in 
the foregoing experiment. The vial, with its con- 
tents, as foon as cold, was placed, in an inverted po- 
fition, over a ciftern of common water (as in Fig. 2.) 
fo that the air, which had been expelled from the 
water, afcended to the upper part of the vial, while 
an equal bulk of the water contained in the vial 
defcended into the bladder. When all the air had 
afcended into the vial, the height at which the water 
flood therein was marked with a diamond.. The 
bladder being then removed, the vial was carefully 
clofed with a cork, and then taken from the ciflern ; 
and the air which it contained was kept therein, until 
it was wanted for the ufe which will be mentioned 
hereafter. 
As foon as the vial was emptied of the air and 
water which it contained, and had been exactly 
weighed, it was filled a fccond time with the Pouhon 
water, which was found to weigh twenty ounces, fe- 
ven drachms, and fourteen grains, apothecaries weight. 
The vial was then emptied to the marks at which the 
•water had flood therein, when in an inverted pofition ; 
and the water remaining in the vial (which now 
filled the fpace that had before been occupied by the 
air 
