CHAP, v.l BALLOONS. 89 



but less than that of the cold air, and its production easier and 

 less expensive. On the 5th of June, 1783, Montgolfier's first ex- 

 periment on a large scale took place, at Annonay, before the States 

 of the Vivarais, accompanied by an immense crowd. A balloon with 

 an opening at its lower end through which the air warmed by a 

 brazier supported by a wire basket ascended into the balloon, rose to 

 a vertical height of two kilometres (6,560 ft.) amid the enthusiastic 

 plaudits of a multitude of spectators. 



The experiment of Annonay, which was considerably applauded, 

 was in less than three months afterwards reproduced in Paris under 

 different conditions. The physicist, Charles, who shared the general 

 ignorance in which Montgolfier had left the public with regard to the 

 nature of the gas which filled his balloon, had the idea also of using 

 hydrogen. He took for the construction of the envelope silk ren- 

 dered impermeable by a coating composed of indiarubber dissolved 

 in boiling spirit of turpentine. The hydrogen was obtained by the 

 reaction of sulphuric acid on iron ; it took several days to produce 

 the quantity of gas necessary for the filling of the balloon. At last 

 on the 27th of August, 1783, the Globe (the name of the first 

 hydrogen-balloon) ascended from the Champ de Mars in presence of 

 an immense crowd, and, after travelling three-quarters of an hour, 

 descended at Gonesse in the suburbs of Paris. At the first bound, it 

 was carried to a vertical height of 1,000 metres ; then, hidden by a 

 cloud, it disappeared, and reappeared in a clear space at a much 

 greater height, and then was again hidden in the clouds. 



This is not the place to give the history of balloon-ascents, which 

 were repeated frequently towards the end of the last century and in 

 our own ; but we have described these two first experiments, not only 

 on account of the stir they made and the enthusiasm they evoked, 

 but because they pointed out two different modes of ascension and 

 two systems of balloons, which were called at the time fire and air 

 balloons respectively. 



This brilliant application of hydrostatic principles and of new 

 physical and chemical discoveries received almost at one bound a 

 great development, while at the present day we are far from having 

 made the most of the means the discovery has placed at our disposal. 



In the first experiments of Montgolfier and Charles, they were 

 contented with the ascent of the balloons themselves ; the idea of 



