The news of this extraordinary experiment soon reached Paris, where it produced a most lively impression. A commission was appointed by the academy of sciences to report upon it. Public curiosity, however, could not await the tardy decision of this body, and accordingly a subscription was entered into to defray the expense, of repeating the Annonay experiment. Such was the excitement that the subscription was filled in a few days, and the construction of the B. was intrusted to the brothers Robert, famous philosophical instrument-makers of the day, and to prof. Charles, a young but experi enced physicist. As the detailed account of the Annonay ascent had not reached Paris, and as nothing was therefore known of the Montgolfier gas, Charles fixed upon hydrogen as the gas most likely to insure success. It was, however, a formidable undertaking to produce it in sufficient abundance for a B., as it was at that time only dealt with in small quantities in the lecture-room. By ingenuity and perseverance combined, he triumphed over this difficulty, and succeeded in filling, in the course of four days, a silk globe of 12 ft. in diameter. This B. was transferred to the Champs de Mars, the largest open space in Paris, where, on the 27th of Aug., 1783, it ascended in the presence of 300,000 spectators, half the population of the city. At the instance of the commission already referred to, Stephen Montgolfier constructed a fire-B., 72 ft. high, and 41 ft. in diameter. It ascended before the commission on the 12th of Sept., 1783, but being held captive, it was much injured by a violent wind which blew at the time, and after it descended it was filially broken up by heavy rains. Another was made of nearly the same dimensions, which ascended on the 19th of the same month at Versailles, the king and royal family " assisting" at the spectacle. This ascent is worthy of note, from the fact that a sheep, a cock, and a duck were placed in an ozier-basket attached to the lower part of the B., and that these first atrial voyagers reached the ground again in safety.
The B. was now a fait accompli, and it began to be seriously discussed whether it might not be serviceable as an air-ship for bearing men aloft as passengers. The solu tion of this question was first given by Pilfitre des Rosiers. In a Montgolfiere, as the heated air-B. was called, 74 ft. high, and 43 ft. in diameter, supporting at its base a gal lery- of wicker-work, lie, in company with the marquis d'ArlandeS, made the first aerial voyage, 21st Nov., 1783. They remained in the air 25 minutes, and sailed across the Seine and over a considerable part of Paris. The year 1783, so fertile in the annals of acrostation, was destined not to pass away without witnessing an additional, and even more satisfactory, triumph. On the 1st of Dec., prof. Charles, along with Robert, rose from the Tuileries gardens with a hydrogen B.—then called a Chartiere--made from the proceeds of a public subscription. This 13. was made of alternately red and yellow gores of silk sewed together, and coated with caoutchouc varnish. It was covered with a net which supported the car, and was furnished with a valve, a barometer, and sand-ballast, and was, in fact, a complete aerial machine. It may be said that the art of aerostation at once attained perfection in Charles's B., and no essential change or improvement has taken place since. In consequence of the danger attending the use of fire-balloons, and the engrossing attention which they demand of the aeronaut, they have now entirely given way to the hydrogen or coal-gas balloons. Before they became obsolete, several remarkable voyages were made in them. The same Pilatre des Rosiers made 30 leagues in one of them, the longest voyage ever executed iu a Montgolfiere. Among the names of the first professional aeronauts, those of Lunardi, Blanchard, and Garnerin deserve special note. Lunardi was the first who made the ascent in Great Britain; and Blanchard, along with the American Dr. Jeffries, crossed the English channel from Dover to Calais in circumstances of almost unparalleled danger, Jan. 7, 1785. Garnerin first descended from a B. by a parachute (q.v.), Oct. 22, 1797. It is much to be regretted that the first aeronaut, Pilfitre des Rosiers, fell a victim to a blind devotion to his art. In order to outvie Blanchard, he constructed a compound machine, consisting of a hydrogen B. above and a Montgolfiere below, and started from Boulogne, accompanied by a young natural philosopher named Remain, on the morning of the 5th of June, 1785. He had not ascended many minutes, when, as it afterwards appeared, on attempting to open the valve of the hydrogen B. by the rope'attached to it, he caused a rent of several yards in it, so that it emptied itself almost immediately, and fell on the Montgolfiere beneath.
The fire in the latter not being kindled, the whole machine fell with a frightful rapidity to the earth. and the ill-fated aeronauts perished on the spot whence they had risen. It is worthy of remark, that though several melancholy incidents of this kind are on record, the number of casualties in the navigation of the air has been less in proportion than in the navigation of the sea. For 1500 aeronauts and 10,000 ascents, calculating approxi mately, only 15 lives have been lost, certainly a small proportion considering dangers and inexperience.
In 1794, during the wars of the revolution, an aerostatic institution was formed at Mention, near Paris, for training a corps of " aerostiers," in order to observe the enemy by means of balloons. A balloon under the management of this corps was present at the battle of Fleurus, near Charleroi, fought against the Austrians. During the siege of Paris, 1S70-71, the B. was extensively employed. Countless letters and several persons left the beleaguered city in balloons. There was, of course, no attempt made to come back in such a conveyance: carrier-pigeons were the return messengers.
Balloons have been enlisted in behalf of science. The first ascent for scientific objects was made at Hamburg, July 18, 1803, by Robertson and Lhoest. The results obtained, more particularly regarding the diminution of terrestrial magnetism, and the general feebleness of electrical and galvanic phenomena in the rarer portions of the atmosphere, were considered of such importance, by the French institute, that another ascent was determined on; MM. Biot and Gay-Lussac were appointed to take the management of the B. and of the physical experiments; and they started, accord ingly, on the 20th Aug., 1804. As this aerial expedition was not altogether successful. a second was undertaken by Gay-Lussac alone, in the same year, in which he rose to a height of 23,000 feet. The observations of the French savants did not confirm those made by Robertson, for after a series of experiments, as careful as their novel situation would admit, they found that no diminution was perceptible in the intensity of electri cal phenomena in the upper air. Since then, many scientific aerial voyages have been undertaken, among which may he mentioned that by Humboldt in America; those made by Mr. Rush, in company with Mr. Green as steersman, on behalf of the British associa tion, during 1847-19; and that by MM. Barral and Bixio (1850) at Paris. Recently, the most remarkable ascents have been made by Mr. Glaishcr for meteorological observation. On one occasion he ascended to a height of 71 in., the barometer standing at 7 inches. The B. contained 90,000 cubic ft. of gas, and carried 600 lbs. The hygrometric and thermometric laws of the air may yet be ascertained by B. ascents, as well as the nature of aerial currents, at present so imperfectly understood. The intro duction of coal-gas, instead of hydrogen, by Mr. Green, is 'the most important advance in aerostation since the earliest days of the art. His large coal-gas B., iu 1830, bore Messrs. Green, Holland, and Mason from London to Weilburg, in Nassau, distant 500 m., in 18 hours. Mention should also be made of the rpindle-shapcd navigable balloons of MM. Girard and De Lime.
In the United States, aerostation has been prosecuted with great zeal. Mr. J. Wise has more than once exploded his B., when high up in the air, to show what he con siders to be always the case, that the fragments with the net-work form in such circum stances a parachute, which moderates the rapidity of descent, and shields the aeronaut from danger. During 1859, the longest flight on record was made by Mr. J. Wise. Mr. La Mountain, and others, who, starting from St. Louis with the intention of reaching New York, succeeded in following the course they had mapped out for themselves until they had crossed lake Erie; when they were caught in an adverse current of air, and forced to abandon their original design, after having traveled 1150 m. in less than 20 hours. In Sept., 1859, Mr. La Mountain made a trip of 300 m. in 4 hours. Mr. Lowe, another American aeronaut, constructed an immense B., which he called an atrial ship, the greatest circumference of which was 387 ft., with a capacity to hold 700.000 cubic ft. of gas, and a lifting-power of 221} tons, and furnished with many new appliances for elevating, and directing the machine.—See Voyages Aeriens (Bni. edit. by T. Glaisher, 1871); Leslallona dirigeablea, Tissandier (1872); "Aeronautics" in Lacy. Bra.; and Quart. Rev., July, 1875.