Or like the dust be tossed
By every sportive wind till all be lost!
—Æschylus.
If desire is sometimes the mother of invention, doubtless the wish to “mix with the clouds,” or “as smoke arise,” suggested to man his first means of aërial locomotion. Indeed this is openly avowed by Joseph Montgolfier. “Smoke rises in the chimney; why not encage this smoke, and have an available force.” But before describing his fundamental experiments of 1783, let us notice the less conspicuous ones, though not less philosophical, of his immediate predecessors in the development of aëronautic science.
It has been seen, that many years before 1783, inventors had clearly conceived the true principle of the balloon, and would be glad to avail themselves of an element of sufficiently low specific gravity for aërial flotation. The desired opportunity came when, in 1766, Henry Cavendish published his experiments, proving that hydrogen is many times lighter than air. Immediately after this, Dr. Black, the famous chemist and natural philosopher of Edinburgh, conceived the idea that a thin light vessel filled with hydrogen should be able to float and rise in the atmosphere, ideas that he conveyed to his friends and expressed in his lectures a year or two after the appearance of Cavendish’s publication. But he contented himself with merely pointing the way to an obviously practicable invention, leaving, as a university professor should, the development of the scientific idea to inventors and constructive engineers.
Intermediate between Dr. Black, the pure scientist, and the Montgolfier brothers manufacturers, came Tiberius Cavallo, an Italian philosopher living in England, who made the first small hydrogen balloons. In a note presented to the Royal Society of London, June 20, 1782, he relates experiments that seem to entitle him to all the credit of inventing the balloon except success on a practical scale. He made hydrogen soap bubbles which rose beautifully in the air, an experiment that has been repeated throughout the world in every chemical laboratory since his day. He made a variety of gum bubbles and varnish bubbles inflated with hydrogen; but curiously enough these failed to rise, though it is known that such bubbles can be made to float handsomely.[5] He inflated carefully prepared gold-beater skin and failed, though gold-beater skin balloons, both large and small, are now a marketable commodity. Finally he constructed paper balloons which he tried to float by use of hydrogen, but without success, though a year later the Montgolfier brothers easily made paper bags arise with hot air, and Professor Charles ascended in a large silk balloon inflated with hydrogen.
The cause of Cavallo’s interesting failures reveals itself in his own account of one of his pioneer experiments. In his History and Practice of Aërostation, he relates that he constructed, of fine Chinese paper, a cylindrical balloon having short conical ends and a calculated buoyancy of twenty-five grains, when properly inflated with hydrogen. This bag, carefully deflated of air by compression between the hands, he suspended above a large bottle connected with it by a glass tube, and supplied with materials for generating hydrogen; in this case a mixture of dilute sulphuric acid and iron filings. When the hydrogen was evolving quite rapidly, he expected to see the paper sac expand and fill out with proportionate speed; but to his surprise it remained perfectly flat, while the room filled with the strong and disagreeable odor of the “inflaminable air.” He then realized that the carefully made sac of paper, which could be so easily inflated with air, was very permeable to hydrogen, allowing it to escape instantly, as through porous cloth, or netting.
Cavallo desisted when the goal was within reach. His plans were practicable, but he abandoned them too readily. Why did he not varnish his balloon when it leaked? He could thus so easily have inaugurated the art of aërial navigation. But after salting the bird’s tail he let it escape.
Various accounts have been given of the steps by which the Montgolfiers were led to their invention of the balloon. They are said to have studied and discussed projects for aërial locomotion a decade before hitting upon their first successful device; at one time filling a paper bag with smoke ineffectually; again with steam, and again trying, but in vain, to employ hydrogen. The following apparently reliable account is given by a friend of the Montgolfiers, Baron Gernando, in his biographical notice of Joseph Montgolfier, having obtained the story from the inventor himself.
Joseph Montgolfier found himself at Abignon, and it was at the time when the combined armies held the siege of Gibraltar. Alone, in the chimney corner, dreaming, as usual, he was contemplating a sort of cut that represented the work of the siege; he grew impatient observing that one could not reach the body of the place either by land or sea. “But could not one arrive there through the air? Smoke rises in the chimney; why not store this smoke in such a manner as to form an available force?” His mind calculated instantly the weight of a given surface of paper, or taffeta; he constructed without delay his little balloon, and saw it rise from the floor, to the great surprise of his hostess, and with a peculiar joy. He wrote on the spot, to his brother then at Annonay: “Prepare immediately a supply of taffeta and cordage, and you shall see the most astonishing thing in the world.”