Some time afterwards, about a year before the Montgolfiers
commenced their experiments which we have already described,
Tiberius Cavallo, an Italian chemist, succeeded in making, with
hydrogen gas, soap-bubbles which rose in the air. Previous to
this he had experimented with bladders and paper bags; but the
bladders he found too heavy, and the paper too porous.

It must not be thought that the Montgolfiers experimented solely
with hot air in the inflation of their balloons. At one time
they used steam, and, later on, the newly-discovered hydrogen
gas; but with both these agents they were unsuccessful. It can
easily be seen why steam was of no use, when we consider that
paper was employed; hydrogen, too, owed its lack of success to
the same cause for the porosity of the paper allowed the gas
to escape quickly.

It is said that the name "balloon" was given to these paper craft
because they resembled in shape a large spherical vessel used
in chemistry, which was known by that name. To the brothers
Montgolfier belongs the honour of having given the name to this
type of aircraft, which, in the two succeeding centuries, became
so popular.

After numerous experiments the public were invited to witness the
inflation of a particularly huge balloon, over 30 feet in
diameter. This was accomplished over a fire made of wool and
straw. The ascent was successful, and the balloon, after rising
to a height of some 7000 feet, fell to earth about two miles
away.