Balloons, Airships, and Flying Machines

by Gertrude Bacon

The first man who appeared to have any inkling of the real way of solving the problem of a “flying chariot,” and who in dim fashion seems to have foreshadowed the invention of the balloon, was that wonderful genius, Roger Bacon, the Learned Friar of Ilchester, the inventor or re-inventor of gunpowder, who lived in the thirteenth century. He had an idea—an idea which was far ahead of his times, and only proved to be true hundreds of years after—that the earth’s atmosphere was an actual substance or “true fluid,” and as such he supposed it to have an upper surface as the sea has, and on this upper surface he thought an airship might float, even as a boat floats on the top of the water. And to make his airship rise upwards to reach this upper sea, he said one must employ “a large hollow globe of copper or other similar metal wrought extremely thin, to have it as light as possible, and filled with ethereal air or liquid fire.”

It is doubtful whether Bacon had very clear ideas of what he meant by “ethereal air.” But, whether by accident or insight, he had in these words hit upon the true principle of the balloon—a principle only put into practice five centuries later. He saw that a body would rise upwards through the air if it were filled with something lighter than air, even as a body will rise upwards through the water if it is made of, or filled with, something lighter than water. We know that if we throw an empty bottle tightly corked into the sea it does not sink, but rises upwards, because it is filled with air, which is lighter than water. In the same way exactly a light bag or balloon which is filled with some gas which is lighter than air will not stay on the surface of the ground, but will rise upwards into the sky to a height which depends upon its weight and buoyancy.

Later philosophers than Bacon came to the same conclusion, though they do not seem to have seen matters more clearly. As recently as 1755 a certain learned French priest actually suggested that since the air on the top of high mountains is known to be lighter than that at an ordinary level, men might ascend to these great heights and bring down the light air “in constructions of canvas or cotton.” By means of this air he then proposed to fly a great machine, which he describes, and which seems to have been as large and cumbersome as Noah’s Ark. Needless to say, the worthy Father’s proposal has never yet been put into practice.

But it is time now that we return to the two brothers Montgolfier and their paper-bag of smoke. Their experiments proved at once that in smoke they had found something which was lighter than air, and which would, therefore, carry a light weight upwards. But of what this something was they had, at the time, but a confused idea. They imagined that the burning fuel they had used had given off some special light gas, with the exact nature of which they were unacquainted. The very word gas, be it here said, was in those days almost unknown, and of different gases, their nature and properties, most people had but the very vaguest notions.

And so for some time the Montgolfiers and their followers supposed that the presence of this mysterious gas was necessary to the success of their experiments, and they were very careful about always using special kinds of fuel, which they supposed gave off this gas, to inflate their bags. Later experiments proved, however, what every one now knows, that the paper-bag rose, not because of the gases given off by the fire, but by reason of the hot air with which it became filled. Nearly all substances, no matter how solid, expand more or less under the influence of heat, and air expands very greatly indeed. By thus expanding heated air becomes lighter than the surrounding air, and, because it is lighter, rises upwards in the atmosphere, and continues to rise until it has once more regained the average temperature.

Montgolfier’s Balloon.

Encouraged by the success of their first humble experiment, the Montgolfiers next tried their paper-bag in the open air, when to their delight it sailed upwards to a height of 70 feet. The next step was to make a much larger craft of 600 cubic feet capacity and spherical in shape, which they called a “Balloon,” because it was in appearance like a large, round, short-necked vessel used in chemistry which was technically known by that name. This great bag, after being inflated, became so powerful that it broke loose from its moorings, and floated proudly upwards 600 feet and more, and came down in an adjoining field. After a few more successful trials the brothers thought that the time had come to make known their new invention. Accordingly they constructed a great balloon of 35 feet in diameter, and issued invitations to the public to come and see the inflation. This was successfully made over a fire of chopped straw and wool, and the giant rose up into the sky amid the deafening applause of a huge multitude, and after attaining a height of 7000 feet, fell to the ground a mile and a half away.

The news of this marvellous event spread like wild-fire throughout the kingdom, and soon not only all France, but all Europe also, was ringing with the tidings. The French Royal Academy of Sciences immediately invited Stephen Montgolfier to Paris, and provided him with money to repeat his experiment. He accordingly constructed a yet larger machine, which stood no less than 72 feet high, had it most magnificently painted and decorated and hung with flags, and sent it up at Versailles in the presence of the King and all his court.

This particular balloon is noteworthy as having been the first of all balloons to carry living passengers into the air. They were three in number, a sheep, a cock, and a duck. Breathlessly the assembled multitude watched these innocent victims placed in the basket and soar calmly and majestically above their heads; and eagerly they followed the balloon to where it fell half a mile away to learn their fate. Would they have been suffocated in those upper regions of the air which no human being had yet explored, or would they be dashed to pieces in the descent? But they found the trio quite uninjured; the unimaginative sheep grazing quietly, and the duck cheerfully quacking. Forthwith the cry then arose that it was time for a man to hazard the ascent, and King Louis, who, like every one else, was vastly excited over the wonder, suggested that two criminals then lying under sentence of death should be sent aloft.