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.
It may be imagined that this experiment aroused enormous interest in Paris, whence the news rapidly spread over all France and to Britain.A Parisian scientific society invited Stephen Montgolfier to Paris in order that the citizens of the metropolis should have their imaginations excited by seeing the hero of these remarkable experiments.Montgolfier was not a rich man, and to enable him to continue his experiments the society granted him a considerable sum of money.He was then enabled to construct a very fine balloon, elaborately decorated and painted, which ascended at Versailles in the presence of the Court.
To add to the value of this experiment three animals were sent up in a basket attached to the balloon.These were a sheep, a cock, and a duck.All sorts of guesses were made as to what would be the fate of the "poor creatures".Some people imagined that there was little or no air in those higher regions and that the animals would choke; others said they would be frozen to death.But when the balloon descended the cock was seen to be strutting about in his usual dignified way, the sheep was chewing the cud, and the duck was quacking for water and worms.
At this point we will leave the work of the brothers Montgolfier.They had succeeded in firing the imagination of nearly every Frenchman, fromKing Louis down to his humblest subject.Strange, was it not, though scores of millions of people had seen smoke rise, and clouds float, for untold centuries, yet no one, until the close of the eighteenth century, thought of making a balloon?
The learned Franciscan friar, Roger Bacon, who lived in the thirteenth century, seems to have thought of the possibility of producing a contrivance that would float in air.His idea was that the earth's atmosphere was a "true fluid", and that it had an upper surface as the ocean has.He quite believed that on this upper surface--subject, in his belief, to waves similar to those of the sea--an air-ship might float if it once succeeded in rising to the required height.But the difficulty was to reach the surface of this aerial sea.To do this he proposed to make a large hollow globe of metal, wrought as thin as the skill of man could make it, so that it might be as light as possible, and this vast globe was to be filled with "liquid fire".Just what "liquid fire" was, one cannot attempt to explain, and it is doubtful if Bacon himself had any clear idea.But he doubtless thought of some gaseous substance lighter than air, and so he would seem to have, at least, hit upon the principle underlying the construction of the modern balloon.Roger Bacon had ideas far in advance of his time, and his experiments made such an impression of wonder on the popular mind that they were believed to be wrought by black magic, and the worthy monk was classed among those who were supposed to be in league with Satan.
