mixed in a bottle 14 parts of that air from
which the fire-air had been removed by liver of sulphur (Sec. 8), and which
I have called vitiated air (Sec. 29), with 4 parts of our fire-air, and
placed the bottle, inverted and open, in a vessel which was also filled
with a solution of liver of sulphur. After 14 days the 4 parts of
fire-air were lost, and the solution had risen into their place.

+44. Third Experiment.+--After I had filled a bottle with our air, I
poured some colourless animal oil into it and closed it tightly. After a
few hours it had already become brown, and by the next day black. It is
no small inconvenience to preserve this oil white in apothecaries'
shops. It is found necessary to pour this oil into small phials, and to
preserve it most carefully from the access of air. When such a
colourless oil is mixed with any acid, the acid, as well as the oil,
becomes black even in an hour, although it has been diluted with water.
Even vinegar has the same effect. There is no other reason, therefore,
why the oil becomes at once black in the air, than that the fire-air
present in the air deprives it of its phlogiston, and thereby develops a
subtle acid, previously united with this phlogiston, which produces the
blackness.

+45. Fourth Experiment.+--(_a._) Into a bottle of 7 ounces, which was
filled with fire-air, I put a piece of phosphorus from urine and closed
it with a cork. I then heated, by means of a burning candle, the place
where the phosphorus lay; the phosphorus took fire with very great
brilliancy. As soon as the flame had gone out, the bottle broke into
fragments.

(_b._) As the bottle in the foregoing experiment was very thin, I
repeated it with a somewhat thicker bottle, and after everything had
become cold I wanted to take the cork out of the bottle under water. It
was not possible for me to do this, however, so tightly did the
external air press the cork into the bottle. Accordingly I forced it
inside the bottle; thereupon water entered the bottle and filled it
almost completely. Since the first bottle was only very thin, the reason
that it was crushed must be ascribed to the external air.

(_c._) When I mixed vitiated air with one third of fire-air, and burned
a piece of phosphorus in the mixture, only 1/3 of it was absorbed.

+46. Fifth Experiment.+--I also repeated the same experiment which is
described in Sec. 19, only with this difference that I took the tube
longer, and filled th