The Mastery of the Air | Page 5

the
indispensable factor of final victory.

CHAPTER II
The French Paper-maker who Invented the Balloon
In the year 1782 two young Frenchmen might have been seen one
winter night sitting over their cottage fire, performing the curious
experiment of filling paper bags with smoke, and letting them rise up
towards the ceiling. These young men were brothers, named Stephen
and Joseph Montgolfier, and their experiments resulted in the invention

of the balloon.
The brothers, like all inventors, seem to have had enquiring minds.
They were for ever asking the why and the wherefore of things. "Why
does smoke rise?" they asked. "Is there not some strange power in the
atmosphere which makes the smoke from chimneys and elsewhere rise
in opposition to the force of gravity? If so, cannot we discover this
power, and apply it to the service of mankind?"
We may imagine that such questions were in the minds of those two
French paper-makers, just as similar questions were in the mind of
James Watt when he was discovering the power of steam. But one of
the most important attributes of an inventor is an infinite capacity for
taking pains, together with great patience.
And so we find the two brothers employing their leisure in what to us
would, be a childish pastime, the making of paper balloons. The story
tells us that their room was filled with smoke, which issued from the
windows as though the house were on fire. A neighbour, thinking such
was the case, rushed in, but, on being assured that nothing serious was
wrong, stayed to watch the tiny balloons rise a little way from the thin
tray which contained the fire that made the smoke with which the bags
were filled. The experiments were not altogether successful, however,
for the bags rarely rose more than a foot or so from the tray. The
neighbour suggested that they should fasten the thin tray on to the
bottom of the bag, for it was thought that the bags would not ascend
higher because the smoke became cool; and if the smoke were
imprisoned within the bag much better results would be obtained. This
was done, and, to the great joy of the brothers and their visitor, the bag
at once rose quickly to the ceiling.
But though they could make the bags rise their great trouble was that
they did not know the cause of this ascent. They thought, however, that
they were on the eve of some great discovery, and, as events proved,
they were not far wrong. For a time they imagined that the fire they had
used generated some special gas, and if they could find out the nature
of this gas, and the means of making it in large quantities, they would
be able to add to their success.

Of course, in the light of modern knowledge, it seems strange that the
brothers did not know that the reason the bags rose, was not because of
any special gas being used, but owing to the expansion of air under the
influence of heat, whereby hot air tends to rise. Every schoolboy above
the age of twelve knows that hot air rises upwards in the atmosphere,
and that it continues to rise until its temperature has become the same
as that of the surrounding air.
The next experiment was to try their bags in the open air. Choosing a
calm, fine day, they made a fire similar to that used in their first
experiments, and succeeded in making the bag rise nearly 100 feet.
Later on, a much larger craft was built, which was equally successful.
And now we must leave the experiments of the Montgolfiers for a
moment, and turn to the discovery of hydrogen gas by Henry
Cavendish, a well-known London chemist. In 1766 Cavendish proved
conclusively that hydrogen gas was not more than one-seventh the
weight of ordinary air. It at once occurred to Dr. Black, of Glasgow,
that if a thin bag could be filled with this light gas it would rise in the
air; but for various reasons his experiments did not yield results of a
practical nature for several years.
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