alkohol first in common air, and
furnishing oxygen gas afterwards to the jar, in proportion as it
consumed; but the carbonic acid gas produced by the process became a
great hinderance to the combustion, the more so that alkohol is but
difficultly combustible, especially in worse than common air; so that
even in this way very small quantities only could be burnt.

Perhaps this combustion might succeed better in the oil apparatus, Pl.
XI.; but I have not hitherto ventured to try it. The jar A in which the
combustion is performed is near 1400 cubical inches in dimension; and,
were an explosion to take place in such a vessel, its consequences would
be very terrible, and very difficult to guard against. I have not,
however, despaired of making the attempt.

From all these difficulties, I have been hitherto obliged to confine
myself to experiments upon very small quantities of alkohol, or at least
to combustions made in open vessels, such as that represented in Pl. IX.
Fig. 5. which will be described in Section VII. of this chapter. If I am
ever able to remove these difficulties, I shall resume this
investigation.

SECT. VI.

_Of the Combustion of Ether._

Tho' the combustion of ether in close vessels does not present the same
difficulties as that of alkohol, yet it involves some of a different
kind, not more easily overcome, and which still prevent the progress of
my experiments. I endeavoured to profit by the property which ether
possesses of dissolving in atmospheric air, and rendering it inflammable
without explosion. For this purpose, I constructed the reservoir of
ether a b c d, Plate XII. Fig. 8. to which air is brought from the
gazometer by the tube 1, 2, 3, 4. This air spreads, in the first place,
in the double lid ac of the reservoir, from which it passes through
seven tubes ef, gh, ik, &c. which descend to the bottom of the
ether, and it is forced by the pressure of the gazometer to boil up
through the ether in the reservoir. We may replace the ether in this
first reservoir, in proportion as it is dissolved and carried off by the
air, by means of the supplementary reservoir E, connected by a brass
tube fifteen or eighteen inches long, and shut by a stop-cock. This
length of the connecting tube is to enable the descending ether to
overcome the resistance occasioned by the pressure of the air from the
gazometer.

The air, thus loaded with vapours of ether, is conducted by the tube 5,
6, 7, 8, 9, to the jar