612 TRANSACTIONS OF THE 



velocity is less than that of the vrind, availed nothing in the air where the 

 velocity of both wind and balloon must be the same ; wings of different 

 constructions proved alike ineffectual, and the navigators were, at length, 

 compelled to confine themselves to raising or lowering the balloon at will, 

 in the rarified air balloons, by increasing or diminishing the fire ; and in the 

 inflammable air balloons, by permitting the gas to escape through a valve> 

 as the only practicable means of governing the course of their vessel by 

 taking advantage of the different currents of air that lie above the variable 

 atmosphere nearest the earth. 



In 1785, Blanchard, prompted by the fate of Rozier and others, who had 

 lost their lives by the destruction of their balloons by fire and other means, 

 constructed the parachute to enable the traveller to desert the balloon in 

 ease of accident, and descend at a uniform rate. 



The French Revolution now broke out, and the balloon soon after began 

 to be applied to practical purposes in rcconnoitering in war. It was first 

 used to effect this on the plains of Fleurus, where the victory of Jourdain, 

 over the Austrians, was chiefly attributable to telegraphic signals made 

 from a balloon under the direction of Guyton Morveau. They served a 

 more valuable purpose in the voyages of MM. Guy de Lussac and Biot, in 

 1804, in determining the degrees of magnetic force at great elevations. 

 Two ascensions were made during this year by MM. Biot and De Lussac, 

 the first to the height of 13,000 feet, and the last to the height of 23,000 

 feet, and valuable results obtained for the science of meteorology. In 

 1806, Carlo Broschi, the royal astronomer at Naples, with Signer Andre- 

 ani, the first Italian aeronaut, attained a height exceeding this elevation, 

 but the atmosphere became so rarified as to burst the balloon, and the 

 adventurous voyagers were precipitated to the ground. Both escaped at 

 the time with their lives, owing to the checking of the velocity by the frag- 

 ments of the machine, but Broschi contracted a disease in his flight of 

 which- he died not long after. 



The longest aerial journey in Europe on record, was made from London, 

 in 1836, by Messrs. Holland, Mason and Greene, who alighted eighteen 

 hours after starting, in the neighborhood of Weilberg, in the duchy of Nas- 

 sau, five hundred miles from the place of ascension. The first balloon 

 ascension in America was made in 1796, from the city of New York, by 

 Blanchard the English aeronaut. 



The next important step in this direction, on this continent, was also 

 made in the city of New York, by Mr. Thomas Bobjohn, a distinguished 

 chronometer and organ maker, in 1847. Mr. Robjohn's -experiments con- 

 sisted of several balloons of different sizes, made in the form of a cigar 

 and moved by screw propellers, turned by means of a coiled spring, and 

 by a small engine worked by steam, generated by a spirit lamp. With 

 these machines he succeeded in obtaining a speed of from four to seven 

 miles an hour, in the old Broadway Tabernacle, and, I believe in the Mer- 

 chants' Exchange, and other places in the city of New York. J^ncouraged 

 by these results he commenced the construction, at Hoboken, N. J., of a 



