experiment
was still more decisive to this purpose. Taking the electric spark upon
_lime-water_, instead of the blue liquor, the lime was precipitated as
the air diminished.

From these experiments it pretty clearly follows, that the electric
matter either is, or contains phlogiston; since it does the very same
thing that phlogiston does. It is also probable, from these experiments,
that the sulphureous smell, which is occasioned by electricity, being
very different from that of fixed air, the phlogiston in the electric
matter itself may contribute to it.

It was now evident that common air diminished by any one of the
processes above-mentioned being the same thing, as I have observed, with
air diminished by any other of them (since it is not liable to be
farther diminished by any other) the loss which it sustains, in all the
cases, is, in part, that of the _fixed air_ which entered into its
constitution. The fixed air thus precipitated from common air by means
of phlogiston unites with lime, if any lime water be ready to receive
it, unless there be some other substance at hand, with which it has a
greater affinity, as the _calces of metals_.

If the whole of the diminution of common air was produced by the
deposition of fixed air, it would be easy to ascertain the quantity of
fixed air that is contained in any given quantity of common air. But it
is evident that the whole of the diminution of common air by phlogiston
is not owing to the precipitation of fixed air, because a mixture of
nitrous air will make a great diminution in all kinds of air that are
fit for respiration, even though they never were common air, and though
nothing was used in the process for generating them that can be supposed
to yield fixed air.

Indeed, it appears, from some of the experiments, that the diminution of
some of these kinds of air by nitrous air is so great, and approaches so
nearly to the quantity of the diminution of common air by the same
process, as to shew that, unless they be very differently affected by
phlogiston, very little is to be allowed to the loss of fixed air in the
diminution of common air by nitrous air.

The kinds of air on which this experiment was made were inflammable air,
nitrous air diminished by iron filings and brimstone, and nitrous air
itself; all of which are produced by the solution of metals in acids;
and also on common air diminished and made noxious, and therefore
deprived of its fixed air by phlo