[ 220 ] 
ferent kind ; for it was whitifh, whereas the other 
had a yellowifh tinge. Except the firft quantity 
of this impregnated water, I could never deprive 
any more that I made of its peculiar tafte. I have 
even let fome of it ftand more than a week, in 
phials with their mouths open, and fometimes 
very near the fire, without producing any altera- 
tion in it. 
Whether any of the fpirit of nitre be properly 
contained in the nitrous air, and be mixed with 
the water in this operation, I have not yet endea- 
voured to determine. This, however, may pro- 
bably be the cafe, as the fpirit of nitre is in a con- 
fiderable degree volatile. 
It will perhaps be thought, that the moft ufe-- 
ful, if not the rnofl remarkable, of all the proper- 
ties of this extraordinary kind of air, is its power 
of preferving animal lubftances from putrefac- 
tion, and of relloring thofe that are already 
putrid, which it poflfeffes in a far greater degree 
than fixed air. My firft oblervation of this was 
altogether cafual. Having found nitrous air to. 
fuffer fo great a diminution as- 1 have already men- 
tioned by a mixture of iron filings and brimftone, 
I was willing to try whether it would be equally 
diminifhed by other caufes of the diminution of 
common air, efpecially by putrefadlion ; and for 
this purpofe I put.a-dead moufe into a quantity of 
it, and placed it near the fire, where the ten- 
dency to putrefaction was very great. In this 
cafe there was a confiderable diminution, viz. from. 
5.1 to 3-1 ; but not fo great as I had expelled, the 
antifeptic power, of the nitrous air having checked' 
