A, into which it is allowed to escape through a
capillary opening, at the extremity of which it is set on fire. The air,
when it has served the purpose of combustion, passes through the bottle
16, Pl. XI. the worm 17, 18, and the deliquescent tube 19, 20, after
which it passes through the alkaline bottles; in these its carbonic acid
gas is absorbed, the water formed during the experiment having been
previously deposited in the former parts of the apparatus.

When I caused construct this apparatus, I supposed that the combination
of atmospheric air and ether formed in the reservoir a b c d, Pl. XII.
Fig. 8. was in proper proportion for supporting combustion; but in this
I was mistaken; for there is a very considerable quantity of excess of
ether; so that an additional quantity of atmospheric air is necessary
to enable it to burn fully. Hence a lamp constructed upon these
principles will burn in common air, which furnishes the quantity of
oxygen necessary for combustion, but will not burn in close vessels in
which the air is not renewed. From this circumstance, my ether lamp went
out soon after being lighted and shut up in the jar A, Pl. XII. Fig. 8.
To remedy this defect, I endeavoured to bring atmospheric air to the
lamp by the lateral tube 10, 11, 12, 13, 14, 15, which I distributed
circularly round the flame; but the flame is so exceedingly rare, that
it is blown out by the gentlest possible stream of air, so that I have
not hitherto succeeded in burning ether. I do not, however, despair of
being able to accomplish it by means of some changes I am about to have
made upon this apparatus.

SECT. VII.

_Of the Combustion of Hydrogen Gas, and the Formation of Water._

In the formation of water, two substances, hydrogen and oxygen, which
are both in the aeriform state before combustion, are transformed into
liquid or water by the operation. This experiment would be very easy,
and would require very simple instruments, if it were possible to
procure the two gasses perfectly pure, so that they might burn without
any residuum. We might, in that case, operate in very small vessels,
and, by continually furnishing the two gasses in proper proportions,
might continue the combustion indefinitely. But, hitherto, chemists have
only employed oxygen gas, mixed with azotic gas; from which
circumstance, they have only been able to keep up the combustion of
hydrogen gas for a very limited time in close vessels, because, as the
resi