of the other, communicate between these receptacles and
a fourth one, which is called the mixture reservoir, since in
it the two gases obtained by the decomposition of the
water do really commingle. The capacity of this fourth
tank is about forty-one cubic feet.

"On the upper part of this tank is a platinum tube
provided with a stopcock.

"You will now readily understand, gentlemen, the apparatus
that I have described to you is really a gas cylinder
and blow-pipe for oxygen and hydrogen, the heat of
which exceeds that of a forge fire.

"This much established, I proceed to the second part
of my apparatus. From the lowest part of my balloon,
which is hermetically closed, issue two tubes a little
distance apart. The one starts among the upper layers of the
hydrogen gas, the other amid the lower layers.

"These two pipes are provided at intervals with strong
jointings of india-rubber, which enable them to move in
harmony with the oscillations of the balloon.

"Both of them run down as far as the car, and lose
themselves in an iron receptacle of cylindrical form,
which is called the heat-tank. The latter is closed at
its two ends by two strong plates of the same metal.

"The pipe running from the lower part of the balloon