gistic processes; and they were
restored to a great degree of purity by agitation in water, out of which
its own air had been carefully boiled.

To five parts of inflammable air, which had been agitated in water till
it was diminished about one half (at which time part of it fired with a
weak explosion) I put one part of nitrous air, which diminished it one
eighth of the whole. This was done in lime-water, without any
precipitation of lime. To compare this with common air, I mixed the same
quantity, viz. five parts of this, and one part of nitrous air: when
considerable crust of lime was formed upon the surface of the lime
water, though the diminution was very little more than in the former
process. It is possible, however, that the common air might have taken
more nitrous air before it was fully saturated, so as to begin to
receive an addition to its bulk.

I agitated in water a quantity of nitrous air phlogisticated with iron
filings and brimstone, and found it to be so far restored, that three
fourths of an ounce measure of nitrous air being put to two ounce
measures of it, made no addition to it.

But the most remarkable of these experiments is that which I made with
_nitrous air_ itself which I had no idea of the possibility of reducing
to a state fit for respiration by any process whatever, at the time of
my former publication on this subject. This air, however, itself,
without any previous phlogistication, is purified by agitation in water
till it is diminished by fresh nitrous air, and to a very considerable
degree.

In a pretty long time I agitated nitrous air in water, supplying it from
time to time with more, as the former quantity diminished, till only one
eighteenth of the whole quantity remained; in which state it was so
wholesome, that a mouse lived in two ounce measures of it more than ten
minutes, without shewing any sign of uneasiness; so that I concluded it
must have been about as good as air in which candles had burned out.
After agitating it again in water, I put one part of fresh nitrous air
to five parts of this air, and it was diminished one ninth part. I then
agitated it a third time, and putting more nitrous air to it, it was
diminished again in the same proportion, and so a fourth time; so that,
by continually repeating the process, it would, I doubt not, have been
all absorbed. These processes were made in lime-water, without forming
any incrustation on the surface of it.

Lastly, I too