{ol CONFINED IN STAGNANT ArrR. III. 
receiver, which he foon returned, and continued 
this alternate exhauftion and return half an hour. 
The fparrows were always kept in air rarified fo 
much as to balance only eight inches and a 
half of mercury, or at moft ten and a half. 
But the fparrow at liberty enjoyed the benefit of 
refpiring renewed air; while that- confined al: 
ways refpired the fame. It expired foon after re- 
moval from the veflel, whereas the other came 
from the receiver in perfect health (1). 
Boyle tells us that animals perifh in condenfed 
air rendered much more elaftic than the atmofphe- 
rical. I have often repeated the experiment, con- 
denfing the air fometimes twice, thrice, or even 
more, than its natural ftate; and with him have ob- 
ferved that the air, thus rendered moft elaftic, 
kills animals flower, but they perifh irrecover- 
ably. 
Thus it is experimentally demonftrated, that 
the diminifhed elafticity of the air is not, and 
cannot be, the efficient caufe of animals dying in 
_clofe veffels. We have next to enquire whether 
their refpiration contributes towards their death ; 
which is the hypothefis now to be difcuffed, and 
will be the fubje¢t of the following chapter. 
(1) Mifcell. T. 2. 
G 3 CILAP, 
