Analyfis of the Air. 245 
down thro* the fyphon, it was forced thro 9 
the valve r, and thence through the fmall 
leaden fyphon into the inverted receiver 
full of water, which water defcended as 
the breath afcended. In this manner I drew 
all the air, except 5 or 6 cubick inches, out 
of the empty receiver at 0, the water at 
the fame time afeending into it and filling 
it 5 by which means ail the air in the empty 
receiver, as alfo all the air in the fyphon 
0 s b, was infpired into my lungs, and breath- 
ed out thro* the valve r into the receiver, 
which was at firft full of water. I marked 
the boundary of air and water, and then 
immerfed the whole receiver, which had 
the breath in it, under water, and there 
gradually poured the contained breath up 
into the other full receiver, which flood 
inverted over 0 s ; whereby I could readily 
find whether the air had loft any of its elaf 
ticity : And for greater furety, I alfo mea- 
fured the bulk of breath by filling the re- 
ceiver with a known quantity of water up 
to the above mentioned mark; making alfo 
due allowance for a bulk of air, equal to 
the capacity of the large fyphon 0 sb> which 
was at laft fucked full of water. 
