40 AERIAL NAVIGATION. 
by throwing out sand, while the ascensive force could be 
controlled by means of the valve. This mode of varying 
the elevation of the balloon was far safer, and in every 
respect more convenient than that adopted with the fire 
balloon. An anchor was provided to help in making a 
successful descent on approaching the ground. Charles 
ascended to the height of nearly two miles on the first 
day of December, 1783, the barometer column sinking to 
20.05 inches, and the thermometer falling from 41° F. to 
21°F. Although this expedition was entirely successful, 
there is no record of his ever making another ascent. 
He was the real inventor of the balloon, and perfected 
it to such an extent that no very important improvement 
was made during the next two-thirds of a century. 
It is rather remarkable that after the experiments just 
described, indicating the rapid development of aerostat- 
ics in France, the first ascent by a human being in any 
other country should be in America, so remote from 
France that the news of Montgolfier’s experiment at An- 
nonay did not reach here until six months afterward. 
The American astronomer, David Rittenhouse, at once 
conceived, independently of Charles, the idea of utilizing 
hydrogen for ballooning purposes. The Philadelphia 
newspapers of December 24 contained brief accounts 
just received in regard to Charles’ experiment of August 
27. In association with his friend, Francis Hopkinson, 
Rittenhouse first tried bladders filled with hydrogen, 
and then made forty-seven small balloons, which were 
filled with the same gas. No account has been trans- 
mitted of the mode of construction adopted. These were 
fastened around a cage in which animals were placed. 
This compound balloon was allowed to ascend, but held 
captive by means of arope. A carpenter, James Wilcox, 
was then induced to ascend, and the rope was cut. He 
rose nearly a hundred feet, and descended by cutting in- 
cisions into several of the balloons. 
