I please; whereas I have often
found abundance of it, when I did not expect it at all.

The nitrous air with which I made the first impregnation of water was
extracted from copper; but when I made the impregnation with air from
quicksilver, the water had the very same taste, though the matter
deposited from it seemed to be of a different kind; for it was whitish,
whereas the other had a yellowish tinge. Except the first quantity of
this impregnated water, I could never deprive any more that I made of
its peculiar taste. I have even let some of it stand more than a week,
in phials with their mouths open, and sometimes very near the fire,
without producing any alteration in it[6].

Whether any of the spirit of nitre contained in the nitrous air be mixed
with the water in this operation, I have not yet endeavoured to
determine. This, however, may probably be the case, as the spirit of
nitre is, in a considerable degree, volatile[7].

It will perhaps be thought, that the most _useful_, if not the most
remarkable, of all the properties of this extraordinary kind of air, is
its power of preserving animal substances from putrefaction, and of
restoring those that are already putrid, which it possesses in a far
greater degree than fixed air. My first observation of this was
altogether casual. Having found nitrous air to suffer so great a
diminution as I have already mentioned by a mixture of iron filings and
brimstone, I was willing to try whether it would be equally diminished
by other causes of the diminution of common air, especially by
putrefaction; and for this purpose I put a dead mouse into a quantity of
it, and placed it near the fire, where the tendency to putrefaction was
very great. In this case there was a considerable diminution, viz. from
5-1/4 to 3-1/4; but not so great as I had expected, the antiseptic power
of the nitrous air having checked the tendency to putrefaction; for
when, after a week, I took the mouse out, I perceived, to my very great
surprize, that it had no offensive smell.

Upon this I took two other mice, one of them just killed, and the other
soft and putrid, and put them both into the same jar of nitrous air,
standing in the usual temperature of the weather, in the months of July
and August of 1772; and after twenty-five days, having observed that
there was little or no change in the quantity of the air, I took the
mice out; and, examining them, found them both perfectly sweet, even
when cut