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Wonderful Balloon Ascents. Camille Flammarion
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isbn 4064066442002
Автор произведения Camille Flammarion
Жанр Математика
Издательство Bookwire
The virtues of the parachute were first tried upon animals. Thus, Blanchard allowed his dog to fall in one from a height of 6,500 feet. A gust of wind caught the falling parachute, and swept it away up above the clouds. Afterwards, the aeronaut in his balloon fell in with the dog in the parachute, both of them high up in the cloudy reaches of the sky, and the poor animal manifested by his barking his joy at seeing his master. A new current separated the aerial voyagers, but the parachute, with its canine passenger, reached the ground safely a short time after Blanchard had landed from his balloon.
Experience has proved that, in the case of a descending parachute, if the rapidity of the descent is doubled the
Garnerin's descent in a Parachute.
resistance of the air is quadrupled; if the rapidity is triple the resistance is increased ninefold; or, to speak in language of science, the resistance of the air is increased by the square of the swiftness of the body in motion. This resistance increases in proportion as the parachute spreads, and thus the uniformity of its fall is established a minute after it has been disengaged from the balloon. We can, therefore, check the descent of a body by giving it a surface capable of distension by the action of the air.
Garnerin, in the year 1802, conceived the bold design of letting himself fall from a height of 1,200 feet, and he accomplished the exploit before the Parisians. When he had reached the height he had fixed beforehand, he cut the rope which connected the parachute with the balloon. At first the fall was terribly rapid; but as soon as the parachute spread out the rapidity was considerably diminished. The machine made, however, enormous oscillations. The air, gathering end compressed under it, would sometimes escape by one side sometimes by the other, thus shaking and whirling the parachute about with a violence which, however great, had happily no unfortunate effect.
The origin of the parachute is more remote than is generally supposed, as there was a figure of one which appeared among a collection of machines at Venice, in 1617.
Another species of parachute, less perfect, to be sure; than that of Garnerin, but still a practical machine, was described 189 years before the great aeronaut's feat at Paris. We read in the narrative of the ambassador of Louis XIV at Siam, at the end of the seventeenth century, the following passage:—"A mountebank at the court of the King of Siam climbed to the top of a high bamboo-tree, and threw himself into the air without any other support than two parasols. Thus equipped, he abandoned himself to the winds, which carried him, as by chance, sometimes to the earth, sometimes on trees or houses, and sometimes into the river, without any harm happening to him."
Is not this the idea of our parachutes?
The First Public Trial of the Balloon—Montgolfier's Balloon, Annonay, June 5th, 1783
CHAPTER IV.
FIRST PUBLIC TRIAL OF THE BALLOON.
(Montgolfier's Balloon, Annonay, 5th of June, 1783.)
We are accustomed to rank the brothers Joseph and Etienne Montgolfier as equally distinguished in the field of science. The reason for thus associating these two names seems to have been the fraternal friendship which subsisted in an extraordinary degree in the Montgolfier family, rather than any equality of claim which they had to the notice of posterity. After special investigation, we find that Joseph Montgolfier was very superior to his brother, and that it is to him principally, if not exclusively, that we owe the invention of aerostation. Nevertheless, we shall not insist upon this fact; and seeing that a sacred amity always cemented a perfect union in the Montgolfier family, we will regard that union as unbroken in any sense, and will not insinuate that the brother of Montgolfier was undeserving of the honoured rank which in his lifetime he held.
In 1783, the sons of Pierre Montgolfier, a rich papermaker at Annonay department of Ardèche, were already in the prime of life, and it is related of them that their principal occupation was experimenting in the physical sciences. Joseph Montgolfier, after being convinced by a number of minor experiments made in 1782 and 1783, that a heat of 180° rarefied the air and made it occupy a space of twice the extent it occupied before being heated—or, in other words, that this degree of heat diminished the weight of air by one half—began to speculate on what might be the shape and the material of a structure which being filled with air thus heated, would be able to raise itself from the earth in spite of the weight of its own covering.
The Brothers Montgolfier.
His first balloon was a small parallelopiped in very thin taffeta, containing less than seventy-eight cubic inches of air. He made it rise to the roof of his apartment—in November, 1782—at Avignon, where he then happened to be. Having returned some little time after to Annonay, Joseph and his brother performed the same experiment, together in the open air with perfect success. Certain, then, of the new principle, they made a balloon of considerable size, containing upwards of sixty-five feet of heated air. This machine likewise rose, tore away the cords by which it was at first held down, and mounting in the air to the height of from two to three hundred feet, fell upon the neighbouring hills after a considerable flight. The brothers Montgolfier then made a very large and strong balloon, with which they wished to bring their discovery before the public.
The appointed day was the 5th of June, 1783 and the nobility of the vicinity were invited to be present at the experiment. Faujas de Saint Fond, author of "La Description des Expériences de la Machine Aérostatique," published the same year, gives the following account of it:—
"What," says Saint Fond, "was the general astonishment when the inventors of the machine announced that immediately it should be full of gas, which they had the means of producing at will by the most simple process, it would raise itself to the clouds! It must be granted that, in spite of the confidence in the ingenuity and experience of the Montgolfiers, this feat seemed so incredible to those who came to witness it, that the persons who knew most about it—who were, at the same time, the most favourably predisposed in its favour—doubted of its success.
"At last the brothers Montgolfier commenced their work. They first of all began to make the smoke necessary for their experiment. The machine—which at first seemed only a covering of cloth, lined with paper, a sort of sack thirty-five feet high—became inflated, and grew large even under the eyes of the spectator, took consistence, assumed a beautiful form, stretched itself on all sides, and struggled to escape. Meanwhile, strong arms were holding it down until the signal was given, when it loosened itself, and with a rush rose to the height of 1,000 fathoms in less than ten minutes."
It then described a horizontal line of 7,200 feet, and as it had lost a considerable amount of gas, it began to descend quietly. It reached the ground in safety; and this first attempt, crowned with such decisive success, secured for ever to the brothers Montgolfier the glory of one of the most astonishing discoveries.
"When we reflect for a moment upon the numberless difficulties which such a bold attempt entailed, upon the bitter criticism to which it would have exposed its projectors had it failed through any