, f [ 186 ] 
clofed with ground floppies, the affinity between 
this noxious air and the common air might be fo 
great, that they would mix through a body of water 
interpofed between them ; the water continually re- 
ceiving from the one, and giving to the other, efpe- 
cially as water receives fome kinds of impregnation 
from, I believe, every kind of air to which it is. con- 
tiguous ; but I have feen no reafon to conclude, that 
a mixture of any kind of air with the common air 
can be produced in this manner. I have kept air in 
which mice have died, air in which candles have 
burned out, and inflammable air, feparated from 
the common air, by the flighted partition of water 
that I could well make, fo that it might not eva* 
porate in a day or two, if I fhould happen not to 
attend to them ; but I found no change in them 
after a month or fix weeks. The inflammable air 
was dill inflammable, mice died indantly'in the ‘air. 
in which other mice had died before, and candles, 
would not burn where they had burned out before. 
Since air tainted with animal or vegetable pu- 
trefa&ion is the- fame thing with air rendered no- 
xious by animal refpiration, I fliall now recite the 
obfervations. which I have made upon this kind of air, 
before I treat of the method of redoring them. 
That thefe two kinds of air are, in fa£t, the fame 
thing, I conclude from their having feveral remark- 
able common properties, and from their differing in 
nothing that I have been able to obferve. They 
equally extinguifh flame, they are equally noxious 
to animals,, they are equally, and in the fame way, 
ofFgnfive to the fmcff, they are equally diminiihed 
