The first aerial voyage across the sea was made by M. Blanchard, in company with Dr. Jeffries, an American physician, who was then residing in England. On the 7th January, 1785, a beautiful frosty winter day, they ascended about one o'clock from the cliff of Dover, with the design of crossing the Channel between England and France, a distance of about twenty-three miles, and, at great personal risk, accomplished their purpose in two hours and a half. The balloon at first rose slowly and majestically in the air, but it soon began to descend, and, before they had crossed the Channel, they were obliged to reduce the weight, by throwing out all their ballast, several books, their apparatus, cords, grapples, bottles, and were even proceeding to cast their clothes into the sea, when the balloon, which had then nearly reached the French coast, began to ascend, and rose to a considerable height, relieving them from the necessity of dispensing with much of their apparel. They landed in safety at the edge of the forest of Guiennes, not far beyond Calais, and were treated by the magistrates of that town with the utmost kindness and hospitality. M. Blanchard had the honor of being presented with 12,000 livres by the King of France. Emboldened by this daring feat, Pilatre de Rozier, already mentioned, and M. Romain, prepared to pay back the compliment of M. Blanchard and Dr. Jeffries, by crossing the Channel from France to England. To avoid the difficulty of keeping up the balloon, which had perplexed and endangered Blanchard and his companion during nearly their whole course, Rozier had recourse to the expedient of placing underneath the hydrogen balloon a fire balloon of smaller dimensions, which was intended to regulate the rising and falling of the whole machine. This promised to unite the advantages of both kinds of balloons, but it unhappily terminated in the melancholy death of the two adventurers. They ascended from Boulogne, on the 15th of June, 1785, but scarcely had a quarter of an hour elapsed from the time of their ascent, when, at the height of 3000 feet, the whole machine was discovered to be in flames. Its scattered fragments, with the mangled bodies of the unfortunate aeronauts, who were probably killed by the explosion of the hydrogen gas, were found near the sea-shore, about four miles from Boulogne. This was the first fatal accident which took place in balloon navigation, though several hundred ascensions had by this time been made.
In the early practice of aerial voyages, the chief danger apprehended was from accidental and rapid descents. To countervail this danger, and enable the adventurer, in cases of alarm, to desert his balloon, and descend to the ground uninjured, Blanchard invented the parachute, or guard for falling, as the word signifies in French, an apparatus very much resembling an umbrella, but of much larger dimensions. The design is to break the fall; and, to effect this, it is necessary that the parachute present a surface sufficiently large to experience from the air such resistance as will cause it to descend with a velocity not exceeding that with which a person can fall to the ground unhurt. During an aerial excursion which Blanchard took from Lisle in August, 1785, when he traversed a distance of not less than 300 miles, he dropped a parachute with a basket fastened to it, containing a dog, from a great elevation, and it fell gently through the air, letting down the animal to the ground in safety. The practice and management of the parachute were subsequently carried much farther by other aeronauts, and particularly by M. Garnerin, an ingenious and spirited Frenchman, who, during the course of his numerous ascents, repeatedly descended from the region of the clouds with that very slender machine. On one occasion, however, he suffered considerable injury in his descent. The stays of the parachute having unfortunately given way, its proper balance was disturbed, and, on reaching the ground, it struck against it with such violence, as to throw him on his face, by which he received some severe cuts. To let down a man of ordinary size from any height, a parachute of a hemispherical form, twenty-five feet in diameter, is required. But although the construction of a parachute is very simple, and the resistance it will meet with from the air in its descent, its size and load being given, can be exactly determined on scientific principles, few have ventured to try it; which may be owing partly to ignorance, or inattention to the scientific principles by which it is governed, and partly to a growing opinion among aeronauts, that it is unnecessary, the balloon itself, in case of its bursting, forming a parachute; as Mr. Wise, the celebrated American aeronaut, experienced on two different occasions, as he narrates in his interesting work on Aeronautics, lately published at Philadelphia—a work to which we have been mainly indebted in drawing up this article.
In the early part of the French revolutionary war, the savants of France, ambitious of bringing to the aid of the Republic all the resources of science, strongly recommended the introduction of balloons, as an effectual means of reconnoitring the armies of their enemies. From the advantages it seemed to promise, the recommendation was instantly acted on by the government, which established an aeronautic school at Meudon, near Paris. The management of the institution, which was conducted with systematic precision, and concealed with the utmost care from the allied powers, was committed to the most eminent philosophers of Paris. Gyton Morveau, a celebrated French chemist, and M. Contel, superintended the operations. Fifty military students were admitted for training. A practicing balloon of thirty-two feet in diameter was constructed, of the most durable materials, and inflated with hydrogen gas. It was kept constantly full, so as to be at all times ready for exercise; and, to make it stationary at any given altitude, it was attached to windlass machinery. Balloons were speedily prepared by M. Contel for the different branches of the French army; the Entreprenant for the army of the north, the Celeste for that of the Sambre and Meuse, the Hercule for that of Rhine and Moselle, and the Intrepide for the memorable army of Egypt. The victory which the French achieved over the Austrians, on the plains of Fleurus, in June, 1794, is ascribed to the observations made by two of their aeronauts. Immediately before the battle, M. Contel and an adjutant-general ascended twice in the war-balloon Entreprenant, to reconnoitre the Austrian army, and though, during their second aerial reconnaissance they were discovered by the enemy, who sent up after them a brisk cannonade, they quickly rose above the reach of danger, and, on descending, communicated such information to their general, as enabled him to gain a speedy and decisive victory over the Austrians.
The balloon was also at an early period taken advantage of for making scientific experiments in the elevated regions of the atmosphere. With the view of ascertaining the force of magnetic attraction, and of examining the electrical properties and constitution of the atmosphere at great elevations, two young, enthusiastic French philosophers, MM. Biot and Gay Lussac, proposed to make an ascent. These gentlemen, who had studied together at the Polytechnic School of Paris, and the latter of whom had especially devoted himself to the study of chemistry, and its application to the arts, while both were deeply versed in mathematical science, were well qualified for the undertaking; and they were warmly patronized by the government, which immediately placed at their command the Intrepide, that had returned with the French army from Egypt to Paris, after the capitulation of Cairo. M. Contel, who had constructed the balloon, was ordered to refit it, under their direction, at the public expense. Having furnished themselves with the philosophical instruments necessary for their experiments—with barometers, thermometers, hygrometers, compasses, dipping needles, metallic wires, an electrophorus, a voltaic pile, and with some frogs, insects, and birds—they ascended, at ten o'clock, on the morning of August 23, 1804, from the garden of the Repository of Models. On rising 6500 English feet, they commenced their observations. The magnetic needle was attracted as usual by iron, but it was impossible for them at this time to determine with accuracy its rate of oscillation, owing to a slow rotary motion with which the balloon was affected. The voltaic pile exhibited all its ordinary effects, giving its peculiar copperas taste, exciting the nervous system, and causing the decomposition of water. At the elevation of 8600 feet, the animals which they carried with them appeared to suffer from the rarity of the air. The philosophers had their pulses much accelerated, but they experienced no difficulty in breathing, nor any inconvenience whatever. Their highest elevation was 13,000 feet; and the result of their experiments at this distance from the earth was, that the force of magnetic attraction had not sensibly diminished, and that there is an increase of electricity in the higher regions of the atmosphere.
In compliance with the request of several philosophers of Paris, who were anxious that the same observations should be repeated at the greatest height that could be reached, Gay Lussac alone made a second ascent, on the morning of September 15, 1804, from the garden of the Repository of Models, and rose, by a gradual ascent, to a great elevation. He continued to take observations at short intervals of the state of the barometer, the thermometer, and the hygrometer, of which he has given a tabular view, but he unfortunately neglected to mark the time at which they were made—a point of material importance, for the results would of course be modified by the progress of the day; and it would have added to their value, had these observations been compared with similar ones made at the same time at the observatory. During the ascent of the balloon, the hygrometer was variable, but obviously marked an increase of dryness; the thermometer indicated a decrease in the heat of the atmosphere, but the decrease is not uniform, the ratio being higher in the elevated regions than in the lower, which are heated from the earth; and it was found, by not fewer than fifteen trials at different altitudes, that the oscillations of a finely-suspended needle varied very little from its oscillations on the surface of the earth. At the height of 21,460 feet. Lussac admitted the air into one of his exhausted flasks, and at the height of 21,790 feet, he filled the other. He continued to rise, till he was 22,912 feet above Paris, or 23,040 feet—that is upward of four miles and a quarter—above the level of the sea, the utmost limit of his ascent, an elevation not much below the summit of Nevado de Sorato, the highest mountain of America, and the loftiest peak of the Himalaya in Asia, the highest mountains in the world, and far above that to which any mortal had ever soared before. One can not but admire the intrepid coolness with which Lussac performed his experiments at this enormous elevation, conducting his operations with the same composure and precision as if he had been seated in his own parlor in Paris. Though warmly clad, he now began to suffer from the excessive cold, his pulse was quickened, he was oppressed by difficulty in breathing, and his throat became parched, from inhaling the dry, attenuated air—for the air was now more than twice as thin as ordinary, the barometer having sunk to 12‧95 inches—so that he could hardly swallow a morsel of bread. He alighted safely, at a quarter before four o'clock afternoon, near the hamlet of St. Gourgan, about sixteen miles from Rouen. On reaching Paris, he hastened to the laboratory of the Polytechnic School, to analyze the air he had brought down in his flasks from the higher regions; and, by a very delicate analysis, it was found to contain exactly the same proportions as the air on the surface of the earth, every 1000 parts holding 215 of oxygen, confirming the identity of the atmosphere in all situations. The ascents of these two philosophers are memorable, as the first which were made for purely scientific purposes.
[From the Dublin University Magazine.]
MAURICE TIERNAY, THE SOLDIER OF FORTUNE
(Continued from Vol. I. Page 797.)