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Other evaporations, which, together with the frefli air 
taken in, may ferve to cool the lungs, and the blood 
palling through them ^ ? 
* As air, even when incorporated with water, does not lofe 
its elafticity, I took it for granted, that it would not become 
lefs elaftic by paffing through the lungs of an animal. But being 
told, that the contrary opinion was held by fome, who fuppofed 
that air, having palled through the lungs of an animal, became 
unfit for refpiration by lofmg its elafticity, I refoh'ed to try how 
the fadl was, by the following experiment. In a receiver eight 
inches diameter, and twelve inches high, having under it a foft 
piece of oylcd leather, I included a pretty large chicken, and tied 
the receiver clofe down to the table ; through a hole in the top 
of the receiver went a glafs tube, open at both ends, cemented 
round the hole with wax, the lower end was immerfed in water 
(tinged blue) which flood in a glafs under the receiver. In 
about an hour after the chicken was included, it grew very much 
diftrefted, gaped wide, and breathed with great difficulty, and 
in half an hour more it feemed almoft ready to expire ; the 
infide of the receiver was then covered with moifture, which in 
fome places ran down in drops. Now if the included air had 
loft any of its elafticity by paffing through the lungs of this ani- 
mal, it could not have prefl'ed fo ftrongly on the water in the 
glafs as it did at firft, and then the external air would have 
preft'ed through the tube, and appeared coming up through the 
water in bubbles ; but no fuch thing happened, for as foon as 
the receiver was tied down, the water in the tube rofe about one 
fifth of an inch above the water in the glafs, and fo continued 
during the whole time of the experiment, except that it rofe 
and fell near one tenth of an inch every time the chicken breath- 
ed ; and thefe vibrations of the water in the tube, I obferved 
grew flower, and moved through a greater fpace towards the 
latter end of the time ; which, fhewed that the chicken then 
took in more air every time it breathed than it diJ at firft. After 
things had flood thus above an hour and a half, and thofe who 
faw the experiment were convinced that the included air had not 
jofl any of its elafticity, though grown quite unfit for refpira- 
tion, the animal being ready to expire in it, I thought it unne- 
c'clfary to confine the chicken any longer, and it foon recovered. 
Air 
I 
