.

The phial which had stood immersed in quicksilver had lost very little
of its original quantity of air; and being now opened in water, and left
there, along with another phial, which was just then filled, as this had
been three years before, viz. with air half inflammable and half fixed,
I observed that the quantity of both was diminished, by the absorption
of the water, in the same proportion.

Upon applying a candle to the mouths of the phials which had been kept
three years, that which had stood in quicksilver went off at one
explosion, exactly as it would have done if there had been a mixture of
common air with the inflammable. As a good deal depends upon the
apertures of the vessels in which the inflammable air is mixed, I mixed
the two kinds of air in equal proportions in the same phial, and after
letting the phial stand some days in water, that the fixed air might be
absorbed, I applied a candle to it, but it made ten or twelve explosions
(stopping the phial after each of them) before the inflammable matter
was exhausted.

The air which had been confined in the corked phial exploded in the very
same manner as an equal and fresh mixture of the two kinds of air in the
same phial, the experiment being made as soon as the fixed air was
absorbed, as before; so that in this case, the two kinds of air did not
seem to have affected one another at all.

Considering inflammable air as air united to, or loaded with phlogiston,
I exposed to it several substances, which are said to have a near
affinity with phlogiston, as oil of vitriol, and spirit of nitre (the
former for above a month), but without making any sensible alteration in
it.

I observed, however, that inflammable air, mixed with the fumes of
smoking spirit of nitre, goes off at one explosion, exactly like a
mixture of half common and half inflammable air. This I tried several
times, by throwing the inflammable air into a phial full of spirit of
nitre, with its mouth immersed in a bason containing some of the same
spirit, and then applying the flame of a candle to the mouth of the
phial, the moment that it was uncovered, after it had been taken out of
the bason.

This remarkable effect I hastily concluded to have arisen from the
inflammable air having been in part deprived of its inflammability, by
means of the stronger affinity, which the spirit of nitre had with
phlogiston, and therefore I imagined that by letting them stand longer
in contact, and esp