he manner represented at _e_ fig. 1. I then put
the phial into a kettle of water, which I set upon the fire and make to
boil. The air expelled by the heat, from the liquor contained in the
phial, issues through the tube, and is received in the bason of
quicksilver, fig. 7. Instead of this suspended bason, I sometimes
content myself with tying a flaccid bladder to the end of the tube, in
both these processes, that it may receive the newly generated air.

In experiments on those kinds of air which are readily imbibed by water,
I always make use of quicksilver, in the manner represented fig. 8, in
which _a_ is the bason of quicksilver, _b_ a glass vessel containing
quicksilver, with its mouth immersed in it, _c_ a phial containing the
ingredients from which the air is to be produced; and _d_ is a small
recipient, or glass vessel designed to receive and intercept any liquor
that may be discharged along with the air, which is to be transmitted
free from any moisture into the vessel _b_. If there be no apprehension
of moisture, I make use of the glass tube only, without any recipient,
in the manner represented _e_ fig. 1. In order to invert the vessel _b_,
I first fill it with quicksilver, and then carefully cover the mouth of
it with a piece of soft leather; after which it may be turned upside
down without any danger of admitting the air, and the leather may be
withdrawn when it is plunged in the quicksilver.

In order to generate air by the solution of metals, or any process of a
similar nature, I put the materials into a phial, prepared in the manner
represented at _e_ fig. 1, and put the end of the glass tube under the
mouth of any vessel into which I want to convey the air. If heat be
necessary I can easily apply to it a candle, or a red hot poker while it
hangs in this position.

When I have occasion to transfer air from a jar standing in the trough
of water to a vessel standing in quicksilver, or in any other situation
whatever, I make use of the contrivance represented fig. 9, which
consists of a bladder, furnished at one end with a small glass tube
bended, and at the other with a cork, perforated so as just to admit the
small end of a funnel. When the common air is carefully pressed out of
this bladder, and the funnel is thrust tightly into the cork, it may be
filled with any kind of air as easily as a glass jar; and then a string
being tied above the cork in which the funnel is inserted, and the
orifice in the oth