[ * 9 $ ] 
(which 1 had kept alive, that the experiment might 
be made on both the kinds of air with the very 
fame animal) would have been fuffieiently recruited, 
fuppofing it to have received any injury by the 
former experiment, was put into the fame veffcl of 
air ; but though it was withdrawn again, after be- 
ing in it hardly one fecond, it was recovered with 
difficulty, not being able to ltir from the place for 
near a minute. After two days, I put the fame 
moufe into an equal quantity of common air, and 
obferved that it continued feven minutes without 
any fign of uneafinefs; and being very uneafy after 
three minutes longer, I took it out. Upon the 
whole, I concluded that the reftored air wanted 
about one fourth of being as wholefome as common 
air. The fame thing alfo appeared when I applied 
the teftof nitrous air. 
In the feven days,, in which the mint was grow- 
ing in this jar of noxious air, three old fhoots had 
extended, themfelves about three inches, and feveral 
new ones had made their appearance in the fame 
time. Dr. Franklin and Sir John Pringle happened 
to be with me, when the plant had been three or 
four days in this ftate, and took notice of its vigorous 
vegetation.,, and remarkably healthy appearance in 
that confinement. 
On the 30th of the fame month, a moufe lived, 
fourteen minutes, breathing naturally all the time, 
and without appearing to be much uneafy, till the 
laft two minutes, in air which had been rendered 
noxious by mice breathing in it ahnoft a year before, 
and which I had found to be mofl highly noxious on 
the 19th of this month, a plant having grown in it,. 
