proportion as they are consumed. I have in another place[20] given a
description of the apparatus used in this experiment, and have explained
the manner of ascertaining the quantities of the gasses consumed with
the most scrupulous exactitude.

In proportion to the advancement of the combustion, there is a
deposition of water upon the inner surface of the baloon or matrass A:
The water gradually increases in quantity, and, gathering into large
drops, runs down to the bottom of the vessel. It is easy to ascertain
the quantity of water collected, by weighing the baloon both before and
after the experiment. Thus we have a twofold verification of our
experiment, by ascertaining both the quantities of the gasses employed,
and of the water formed by their combustion: These two quantities must
be equal to each other. By an operation of this kind, Mr Meusnier and I
ascertained that it required 85 parts, by weight, of oxygen, united to
15 parts of hydrogen, to compose 100 parts of water. This experiment,
which has not hitherto been published, was made in presence of a
numerous committee from the Royal Academy. We exerted the most
scrupulous attention to its accuracy; and have reason to believe that
the above propositions cannot vary a two hundredth part from absolute
truth.

From these experiments, both analytical and synthetic, we may now affirm
that we have ascertained, with as much certainty as is possible in
physical or chemical subjects, that water is not a simple elementary
substance, but is composed of two elements, oxygen and hydrogen; which
elements, when existing separately, have so strong affinity for caloric,
as only to subsist under the form of gas in the common temperature and
pressure of our atmosphere.

This decomposition and recomposition of water is perpetually operating
before our eyes, in the temperature of the atmosphere, by means of
compound elective attraction. We shall presently see that the phenomena
attendant upon vinous fermentation, putrefaction, and even vegetation,
are produced, at least in a certain degree, by decomposition of water.
It is very extraordinary that this fact should have hitherto been
overlooked by natural philosophers and chemists: Indeed, it strongly
proves, that, in chemistry, as in moral philosophy, it is extremely
difficult to overcome prejudices imbibed in early education, and to
search for truth in any other road than the one we have been accustomed
to follow.

I shall fi