Th CONFINED IN STAGNANT AIR, oF 
fearches were chiefly directed to them: but no- 
body that I know of has made experiments on an 
animal partaking both of the. nature of a bird 
and a quadruped, although it is not properly ei- 
ther the one or the other;. I mean the bat.; an 
animal fo difgufting and forbidding in appear- 
ance, but at the fame time as: perfect:as other ani- 
mals, and the connection of quadrupeds. with 
birds. Their ambiguous nature made me defir= 
ous-of forcing them tovrefpire the fame air in 
clofe veffels :. but it firft occurred to try how © 
long they could fupport:a vacuum.. How much 
fooner did they die than the cold blooded ani-« 
mals? Five bats, fucceffively fubje€ted tothe 
experiment, did not live three minutes. They 
were of that fpecies called, by M. D’Aubenton, 
the horfe-fhoe bat, from the circular line on the 
noles ° 
_PFhough they died fuddenly in vacuo, there 
was.a limited proportion in confined air. Four, 
clofed up in a veflel, lived fcarcely an hour; two, 
an hour and a half; one, lived almoft three 
hours.. ‘The water of the veffel, in the firft cafe, 
afcended an inch and feven lines; in the fe- 
eond with two, am inch and three lines ; and in 
that with one, eleven lines. 
My experiments were extended to feveral rep» 
tiles; namely, vipers and fome land fnakes. Both 
thefe fpecies having died in clofe veffels ; the water 
rofe to a certain degree as the number was greater. 
The: 
