did not at all increase, I extinguished the fire, and allowed the
vessels to cool. The bulk of air in the body and neck of the matrass,
and in the bell-glass, reduced to a medium of 28 inches of the
barometer and 10 (54.5 ) of the thermometer, at the commencement of the
experiment was about 50 cubical inches. At the end of the experiment the
remaining air, reduced to the same medium pressure and temperature, was
only between 42 and 43 cubical inches; consequently it had lost about
1/6 of its bulk. Afterwards, having collected all the red particles,
formed during the experiment, from the running mercury in which they
floated, I found these to amount to 45 grains.
I was obliged to repeat this experiment several times, as it is
difficult in one experiment both to preserve the whole air upon which we
operate, and to collect the whole of the red particles, or calx of
mercury, which is formed during the calcination. It will often happen in
the sequel, that I shall, in this manner, give in one detail the results
of two or three experiments of the same nature.
The air which remained after the calcination of the mercury in this
experiment, and which was reduced to 5/6 of its former bulk, was no
longer fit either for respiration or for combustion; animals being
introduced into it were suffocated in a few seconds, and when a taper
was plunged into it, it was extinguished as if it had been immersed into
water.
In the next place, I took the 45 grains of red matter formed during this
experiment, which I put into a small glass retort, having a proper
apparatus for receiving such liquid, or gasseous product, as might be
extracted: Having applied a fire to the retort in a furnace, I observed
that, in proportion as the red matter became heated, the intensity of
its colour augmented. When the retort was almost red hot, the red matter
began gradually to decrease in bulk, and in a few minutes after it
disappeared altogether; at the same time 41-1/2 grains of running
mercury were collected in the recipient, and 7 or 8 cubical inches of
elastic fluid, greatly more capable of supporting both respiration and
combustion than atmospherical air, were collected in the bell-glass.
A part of this air being put into a glass tube of about an inch
diameter, showed the following properties: A taper burned in it with a
dazzling splendour, and charcoal, instead of consuming quietly as it
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