The magnetic force did not experience any sen-
sible variation at the different heights. The
next ascent of importance was that of Barral
and Bixto in July, 18.50. In this ascent, at
19,700 feet, the aëronauts observed a tempera-
ture in a cloud of 15° F., and at 23,000 feet
above the cloud a temperature of — 38° F. The
ascent of James Glaisher in 1862 has already
been noted for its extreme height, and there have
been several other ascents of less height from
which fruitful scientific results have been ob-
tained. On March 21, 1893, a balloon 19.7 feet
in diameter, carrying a self-registering barometer
and thermometer, was sent up from Paris. The
records made by these instruments were exam-
ined when the balloon descended, and appeared
to show that the balloon rose to a height of
45,920 feet, when the ink froze at a tempera-
ture of — 32° C, and the record was discontinued
until at a height of 52,490 feet the ink was
thawed by solar radiation and the record was
resumed. The accuracy of these figures has been
seriously questioned, but if they are accurate
the balloon reached a height of nearly 10 miles.
At the Paris Exposition of 1900, competitive long distance balloon trips were undertaken by a number of aëronauts on September 30 and October 9. In the first trial, or race, as it was popularly termed, there were twelve starters, of which only four succeeded in making records of a notable character. Starting from the Vincennes Field, Paris, Comte de Castillon de Saint-Victor, in the Orient, reached Cordof in Schleswig-Holstein, 496 miles, in 14 hours; M. Faure, in the Aëro-Club, reached Mamlitz, in Posen, eastern Prussia, 733 miles; M. Jacques Balsan, in the Saint Louis, reached Danzig, eastern Prussia, 757 miles, in 22 hours, and the Comte de la Vaulx, in the Centaure, reached Wloclawek, in Russian Poland, 766 miles, in 21 hours and 30 minutes. In the second trial of October 9, there were six starters, of whom only two deserve particular mention, namely, the Comte de la Vaulx, in the Centaure, and M. Jacques Balsan, in the Saint Louis, both competitors in the first trial. Starting from Paris, M. le Comte de la Vaulx readied Korostichev, in Russia, 1193 miles, in 36 hours and 45 minutes. The extreme altitude attained was 18,810 feet. M. Jacques Balsan reached Radom, Poland, 843 miles from Paris, in 27 hours and 25 minutes. The maximum altitude reached was 21,582 feet. The Centaure of the Comte de la Vaulx, which made the best record, was a balloon of 1650 cubic meters capacity, and had made several notable ascents previous to its record-breaking voyage beginning October 9, 1900. The most remarkable of these previous voyages was one from Paris to Sweden, 824 miles. In the famous 1193 mile journey to Russia, the Centaure was filled with a mixture of hydrogen and of common illuminating gas.
Military Ballooning. The first use of balloons for this purpose was made under the first French Republic by the chemist Guyton de Morveau, and two companies of military balloonists were organized under the command of De Coutelle and sent to the field. The L'Entreprenant, a balloon 27 feet in diameter, was at Maubeuge, June 2, 1794, doing excellent service for the French, and again at Charleroi, from June 21 to 25. The balloons used were of the captive type, held by ropes. During the battle of Fleurus, the L'Entreprenant remained ten hours in the air, and gave General Jourdan all details of the Austrian movements. During the Civil War in the United States, La Montain reconnoitred the Confederate position from a captive balloon near Washington, but finding his observations insufficient, he cut the cable which held the balloon and passed over the enemy's army. Landing in Maryland, he was able to afford General McClellan important information concerning the enemy's movements. The balloon Rhode Island, also used in the Civil War, was the first used in communicating directly with a military post, by means of a wire conductor attached to the anchoring cable, and thus transmitted observations telegraphically to the ground. Later in the war, from a balloon before Richmond, at an altitude of 300 meters (about 980 feet), panoramic photographs were taken of the terrain and surrounding country. In 1870 the Germans before Strassburg made ineffectual attempts to utilize balloons. In this respect the French were more successful, using balloons during the siege of Paris to communicate with the outer world. A school of aërostation was founded in Germany in 1884, under command of Major Buchols. Ascensions were made at the manœuvres near Cologne in 1885, and these experiments were renewed at Mainz in 1887. The German officers also made experiments with luminous balloons for signaling, using an electric lamp in the interior of the balloon. By means of an electric projector carried up by a balloon, they were able to throw light on the terrain at a great distance. Optic telegraphy was the subject of experiments and study in Russia in 1884, and trials were made with arc lights suspended under the balloon and connected with the ground by conductors. In 1879 the English organized a company of military balloonists, and a park of construction for balloons was established at Woolwich. In the Egyptian campaign in 1885 military ballooning was used to advantage. The balloon section was used in South Africa, 1899-1901, with some measure of success.
The balloon was used as an actual means of offense at the siege of Verona, 1849, by the Austrians, who transported in balloons missiles of war, which they threw down upon the enemy. This method of warfare, which has often been proposed, has not been found successful, largely owing to the difficulty in dropping the missiles accurately, slight wind currents deflecting them.
Mechanical Flight. Attempts to imitate the flight of birds by mechanical contrivances antedate the balloon by several hundred years. Several very early instances are on record of persons who, apparently by some parachute-like contrivance, descended obliquely from high towers to a considerable distance; thus in the thirteenth or fourteenth century, Elmerus, a monk, is said to have flown more than a furlong from the top of a tower in Spain, but the distance is probably much exaggerated; and in the seventeenth century, Besnier, a locksmith of Sable, in France, after experiments from windows one story high was able to leap safely from very elevated positions, and to pass over houses or over rivers of considerable breadth. The first properly authenticated account of an artificial wing was given by Borelli in 1670, and his investigations and experiments furnished the principal basis for experiments until 1867. In this year Professor J. B. Pettigrew, an English scientist, pub-
