ommon way.

In order to ascertain what addition, with respect to quantity and
weight, water would acquire by being saturated with alkaline air, I put
1-1/4 grains of rain-water into a small glass tube, closed at one end
with cement, and open at the other, the column of water measuring 7/10
of an inch; and having introduced it through the quicksilver into a
vessel containing alkaline air, observed that it absorbed 7/8 of an
ounce measure of the _air_, and had then gained about half a grain in
weight, and was increased to 8-1/2 tenths of an inch in length. I did
not make a second experiment of this kind, and therefore will not answer
for the exactness of these proportions in future trials. What I did
sufficiently answered my purpose, in a general view of the subject.

When I had, at one time, saturated a quantity of distilled water with
alkaline air, so that a good deal of the air remained unabsorbed on the
surface of the water, I observed that, as I continued to throw up more
air, a considerable proportion of it was imbibed, but not the whole; and
when I had let the apparatus stand a day, much more of the air that lay
on the surface was imbibed. And after the water would imbibe no more of
the _old_ air, it imbibed _new_. This shews that water requires a
considerable time to saturate itself with this kind of air, and that
part of it more readily unites with water than the rest.

The same is also, probably, the case with all the kinds of air with
which water can be impregnated. Mr. Cavendish made this observation with
respect to fixed air, and I repeated the whole process above-mentioned
with acid air, and had precisely the same result. The alkaline water
which I procured in this experiment was, beyond comparison, stronger to
the smell, than any spirit of sal ammoniac that I had seen.

This experiment led me to attempt the making of spirit of sal ammoniac
in a larger quantity, by impregnating distilled water with this alkaline
air. For this purpose I filled a piece of a gun-barrel with the
materials above-mentioned, and luted to the open end of it a small glass
tube, one end of which was bent, and put within the mouth of a glass
vessel, containing a quantity of distilled water upon quicksilver,
standing in a bason of quicksilver, as in fig. 7. In these circumstances
the heat of the fire, applied gradually, expelled the alkaline air,
which, passing through the tube, and the quicksilver, came at last to
the water, which,