rate trials were quickly developed, and
the infant balloon grew fast. One worthy of the name, spherical in shape
and of some 600 cubic feet capacity, was now made and treated as before,
with the result that ere it was fully inflated it broke the strings that
held it and sailed away hundreds of feet into the air. The infant
was fast becoming a prodigy. Encouraged by their fresh success, the
inventors at once set about preparations for the construction of a much
larger balloon some thirty-five feet diameter (that is, of about 23,000
cubic feet capacity), to be made of linen lined with paper and this
machine, launched on a favourable day in the following spring, rose with
great swiftness to fully a thousand feet, and travelled nearly a mile
from its starting ground.

Enough; the time was already ripe for a public demonstration of the new
invention, and accordingly the 5th of the following June witnessed the
ascent of the same balloon with due ceremony and advertisement. Special
pains were taken with the inflation, which was conducted over a pit
above which the balloon envelope was slung; and in accordance with the
view that smoke was the chief lifting power, the fuel was composed of
straw largely mixed with wool. It is recorded that the management of
the furnace needed the attention of two men only, while eight men could
hardly hold the impatient balloon in restraint. The inflation, in spite
of the fact that the fuel chosen was scarcely the best for the purpose,
was conducted remarkable expedition, and on being released, the
craft travelled one and a half miles into the air, attaining a height
estimated at over 6,000 feet.

From this time the tide of events in the aeronautical world rolls on in
full flood, almost every half-year marking a fresh epoch, until a new
departure in the infant art of ballooning was already on the point of
being reached. It had been erroneously supposed that the ascent of the
Montgolfier balloon had been due, not to the rarefaction of the air
within it--which was its true cause--but to the evolution of some light
gas disengaged by the nature of the fuel used. It followed, therefore,
almost as a matter of course, that chemists, who, as stated in the last
chapter, were already acquainted with so-called "inflammable air," or
hydrogen gas, grasped the fact that this gas would serve better than any
other for the purposes of a balloon. And no sooner had the news of the
Montgolfiers' success reached Par