circumstances, which I am not to suppose the reader to know, I shall
only observe, that the ether, from this experiment, is almost only
capable of existing in the aeriform state in our world; for, if the
weight of our atmosphere was only equal to between 20 and 24 inches of
the barometer, instead of 28 inches, we should never be able to obtain
ether in the liquid state, at least in summer; and the formation of
ether would consequently be impossible upon mountains of a moderate
degree of elevation, as it would be converted into gas immediately upon
being produced, unless we employed recipients of extraordinary strength,
together with refrigeration and compression. And, lastly, the
temperature of the blood being nearly that at which ether passes from
the liquid to the aeriform state, it must evaporate in the primae viae,
and consequently it is very probable the medical properties of this
fluid depend chiefly upon its mechanical effect.

These experiments succeed better with nitrous ether, because it
evaporates in a lower temperature than sulphuric ether. It is more
difficult to obtain alkohol in the aeriform state; because, as it
requires 67 deg. (182.75 deg.) to reduce it to vapour, the water of the
bath must be almost boiling, and consequently it is impossible to plunge
the hands into it at that temperature.

It is evident that, if water were used in the foregoing experiment, it
would be changed into gas, when exposed to a temperature superior to
that at which it boils. Although thoroughly convinced of this, Mr de la
Place and myself judged it necessary to confirm it by the following
direct experiment. We filled a glass jar A, (Plate VII. Fig. 5.) with
mercury, and placed it with its mouth downwards in a dish B, likewise
filled with mercury, and having introduced about two gross of water into
the jar, which rose to the top of the mercury at CD; we then plunged the
whole apparatus into an iron boiler EFGH, full of boiling sea-water of
the temperature of 85 deg. (123.25 deg.), placed upon the furnace GHIK.
Immediately upon the water over the mercury attaining the temperature of
80 deg. (212 deg.), it began to boil; and, instead of only filling the
small space ACD, it was converted into an aeriform fluid, which filled
the whole jar; the mercury even descended below the surface of that in
the dish B; and the jar must have been overturned, if it had not been
very thick and heavy, and fixed to the dish by means of iron-wire