"I therefore resolved to go about the thing more directly;
so, at the start, I dispensed with ballast altogether,
excepting as a provision for cases of special emergency,
such as the breakage of my apparatus, or the necessity of
ascending very suddenly, so as to avoid unforeseen obstacles.

"My means of ascent and descent consist simply in dilating
or contracting the gas that is in the balloon by the
application of different temperatures, and here is the
method of obtaining that result.

"You saw me bring on board with the car several
cases or receptacles, the use of which you may not have
understood. They are five in number.

"The first contains about twenty-five gallons of water,
to which I add a few drops of sulphuric acid, so as to
augment its capacity as a conductor of electricity, and then I
decompose it by means of a powerful Buntzen battery.
Water, as you know, consists of two parts of hydrogen to
one of oxygen gas.

"The latter, through the action of the battery, passes
at its positive pole into the second receptacle. A third
receptacle, placed above the second one, and of double its
capacity, receives the hydrogen passing into it by the
negative pole.

"Stopcocks, of which one has an orifice twice the size