Animated by these successful results, Mr Charles and the two Messrs Roberts resolv,d upon attempting an aerial voyage, in a balloon filled with inflammable air. One was accordingly prepared by the Messrs Roberts, of varnished silk, of a spherical form, 27 feet in diame ter, which had a car suspended to it, for the accommo dation of two adventurers. To prevent any danger from the expansion of the air, the balloon was furnished with a valve, formed in such a manner as to permit the free discharge of gas when occasion required. On the 17th December, 1783, Mr Charles, and one of the Roberts, having previously ascertained the direction of the wind, by launching a small balloon, ascended from Paris to the height of 600 feet, and after a voyage of an hour and three quarters, descended at a distance of 27 miles from the place of their departure. The balloon being then rendered 130 pounds lighter by Mr Roberts leaving his station, Mr Charles set out alone in the car, and in 20 minutes found himself elevated 9000 feet above the surface of the earth. At this immense height, all ter restrial objects had totally disappeared from his view. The thermometer stood at when he left the earth; but in the space of ten minutes it fell to 21°. The effects which so rapid a change of situation produced upon his body, were violent in the extreme. He was benumbed with cold, and felt a severe pain in his right ear and jaw. The balloon passed through different currents of air ; and in the higher regions, the expansion of the gas was so powerful, that Mr Charles was obliged to allow part of it to escape, in order to prevent the burst ing of the balloon. Alter having risen to the height of 10,500 feet, he came down about a league from the place of ascent. The balloon, including the two aero nauts, thermometer, barometer, and ballast, weighed 640 pounds ; and the inflammable gas was found, on calculation, to be about 54. times lighter than common air.
M. Jean Pierre Blanchard, an ingenious French gen tleman, who had been projecting some mechanical con trivances for flying, constructed a balloon, 27 feet in diameter, and being accompanied by a Benedictine friar, lie ascended from Parts on the 2d March, 1784. After rising 15 feet, the balloon was precipitated upon the ground with a violent shock, and the friar, apprehen sive of his safety, was induced to abandon his seat. Mr Blanchard then ascended alone to the height of 9600 feet. He met with different currents of air. He felt extreme cold, and being oppressed with drowsiness, he descended after a voyage of an hour and a quarter. In order to direct his course, he employed on this occa sion an apparatus, consisting of a rudder and two wings, which were attached to the car, but found that it excit ed little or no influence over the balloon, either in this or subsequent voyages.
In April 1784, Messrs Morveau and Bertrand adopt ed a similar expedient, \vhich they found to operate very sensibly on the direction of their balloon. They rose about 13,000 feet high, where they enjoyed one of the most sublime and magnificent prospects that the ima gination could conceive. The mass of clouds that float ed in silent disorder through the regions below, pre sented the appearance of a serene and boundless ocean, while a beautiful parhelion of concentric circles, that began to form as the sun was going down, heightened the grandeur of the scene. In the month of June fol
lowing, M. de Morveau undertook another voyage, which, as well as the former, commenced at Dijon. His bal loon was 25 feet in diameter, and made of varnished taffeta.
A similar device for regulating the course of the bal loon was resorted to by the Messrs Roberts, who had before ascended together. Their former balloon was converted into an oblong spheroid, 46 feet by 27, the longer axis being parallel to the horizon ; and the car, which was 17 feet long, had five wings or oars disposed around it, for the purpose of steering. The Messrs Roberts, and Al. Collin Hullin, upon entering the car, threw out 24 pounds of ballast, which produced a gen tle ascent. The current of air between the altitudes of 600 and 4200 feet was uniform. On arriving at the height of 14,000 feet, they encountered some stormy clouds, which they endeavoured to avoid, by alternately ascerding and descending. In three hours from their ascent, they heard two peals of thunder, when the ther mometer fell from 77° to 59°. Finding themselves soon afterwards becalmed, they had recourse to their oars, by the exertion of which, their balloon, in 35 minutes, described an elliptical segment, whose shortest diame ter was 6000 feet. After travelling 150 miles, in the space of six hours and a half, they descended in safety.
The Messrs Roberts, accompanied by the late duke of Orleans, and a fourth person, ascended in July 1781, in a balloon different in its structure from any that had hitherto been tried. On all former occasions, aeronauts had found the method of effecting a descent by a dis charge of gas, attended with inconvenience ; and to obviate this difficulty, the Messrs Roberts had suspend ed a small balloon within the large one. The interior balloon was to be filled with common air, by means of bellows attached to it, whenever they wished to descend ; it being justly supposed, that the addition of common air would increase the weight, as its diminution would, on the other hand, lighten the balloon. This expedient, however, though promising in theory, did not answer in practice. In the space of three minutes, they rose to a height where not an object was to be seen but the clouds that surrounded them. The balloon, no longer obeying their management, was tossed, with the most violent agitation, as if from one whirlwind to another. The cords, by which the interior balloon was suspended, being cut, it fell down in such a position as completely to close up the aperture which communicated between the large balloon and the car. A sudden gust of wind next drove them beyond the region of the storm ; but the expansion of the inflammable air increasing, they dreaded the bursting of the balloon ; and being unable to remove the small one, which obstrut tcd the aperture. they continued to ascend. It was then rent in two places ; and notm ithstanihng the imminent danger to which they were exposee, irom the rapid it) of its de scent, they all landed Indio] t.