ainly distinguishable from
it) adhering to it. Sometimes I have perceived the flame of the candle,
in these circumstances, to be twice as large as it is naturally, and
sometimes not less than five or six times larger; and yet without any
thing like an _explosion_, as in the firing of the weakest inflammable
air.

Nor is the farther progress in the transmutation of nitrous air, in
these circumstances, less remarkable. For when it has been brought to
the state last mentioned, the agitation of it in fresh water almost
instantly takes off that peculiar kind of inflammability, so that it
extinguishes a candle, retaining its noxious quality. It also retains
its power of diminishing common air in a very great degree.

But this noxious quality, like the noxious quality of all other kinds of
air that will bear agitation in water, is taken out of it by this
operation, continued about five minutes; in which process it suffers a
farther and very considerable diminution. It is then itself diminished
by fresh nitrous air, and animals live in it very well, about as well as
in air in which candles have burned out.

Lastly, One quantity of nitrous air, which had been exposed to iron in
quicksilver, from December 18 to January 20, and which happened to stand
in water till January 31 (the iron still continuing in the phial) was
fired with an explosion, exactly like a weak inflammable air. At the
same time another quantity of nitrous air, which had likewise been
exposed to iron, standing in quicksilver, till about the same time, and
had then stood in water only, without iron, only admitted a candle to
burn in it with an enlarged flame, as in the cases above mentioned. But
whether the difference I have mentioned in the circumstances of these
experiments contributed to this difference in the result, I cannot tell.

Nitrous air treated in the manner above mentioned is diminished about
one fourth by standing in quicksilver; and water admitted to it will
absorb about half the remainder; but if water only, and no quicksilver,
be used from the beginning, the nitrous air will be diminished much
faster and farther; so that not more than one fourth, one sixth, or one
tenth of the original quantity will remain. But I do not know that there
is any difference in the constitution of the air which remains in these
two cases.

The water which has imbibed this nitrous air exposed to iron is
remarkably green, also the phial containing it becomes deeply