least, since the decomposition which took place daily before their eyes
was entirely unnoticed. But we mean to prove, that water is by no means
a simple or elementary substance. I shall not here pretend to give the
history of this recent, and hitherto contested discovery, which is
detailed in the Memoirs of the Academy for 1781, but shall only bring
forwards the principal proofs of the decomposition and composition of
water; and, I may venture to say, that these will be convincing to such
as consider them impartially.
_Experiment First._
Having fixed the glass tube EF, (Pl. vii. fig. 11.) of from 8 to 12
lines diameter, across a furnace, with a small inclination from E to F,
lute the superior extremity E to the glass retort A, containing a
determinate quantity of distilled water, and to the inferior extremity
F, the worm SS fixed into the neck of the doubly tubulated bottle H,
which has the bent tube KK adapted to one of its openings, in such a
manner as to convey such aeriform fluids or gasses as may be disengaged,
during the experiment, into a proper apparatus for determining their
quantity and nature.
To render the success of this experiment certain, it is necessary that
the tube EF be made of well annealed and difficultly fusible glass, and
that it be coated with a lute composed of clay mixed with powdered
stone-ware; besides which, it must be supported about its middle by
means of an iron bar passed through the furnace, lest it should soften
and bend during the experiment. A tube of China-ware, or porcellain,
would answer better than one of glass for this experiment, were it not
difficult to procure one so entirely free from pores as to prevent the
passage of air or of vapours.
When things are thus arranged, a fire is lighted in the furnace EFCD,
which is supported of such a strength as to keep the tube EF red hot,
but not to make it melt; and, at the same time, such a fire is kept up
in the furnace VVXX, as to keep the water in the retort A continually
boiling.
In proportion as the water in the retort A is evaporated, it fills the
tube EF, and drives out the air it contained by the tube KK; the aqueous
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