AERIAL NAVIGATION. 295 



by supporting himself in the air for a time. He started from an elevated posi- 

 tion, and came down by degrees. Dante, a mathematician, also tried to fly, but 

 without great success. He broke his thigh on one occasion. Laurence de 

 Gusman claimed an invention for flying in 1709, and petitioned for a "patent," 

 which was granted by the king's letter. The machine appears to have 

 borne some resemblance to a bird. 



It was not till 1782, however, that the true art of aerial navigation was 

 discovered. The knowledge of hydrogen gas possessed by Cavendish in 

 1766 no doubt led up to it, and in the year following its discovery 

 Professor Black, lecturing in Edinburgh, stated that it was much lighter 



Fig. 293. Montgolfier balloon. 



than the atmosphere, and that any vessel filled with the gas would rise in 

 the air. We now come to the invention of the BALLOON (so called from its 

 shape being similar to a vessel used in the laboratory) by the Brothers 

 Montgolfier. 



Stephen and James Montgolfier were paper-makers, and carried on 

 their business at Annonay, near Lyons, but it was partly by accident that the 

 great discovery was made. They had no knowledge of the buoyancy of 

 hydrogen gas. They took their idea of the balloon (inflated) from noticing 

 an ascending column of smoke. It occurred to Stephen that if a paper bag 

 were filled with smoke it would ascend into the air. A large bag was made 

 and some paper burnt beneath it in a room. When the smoke had filled 

 the bag it was released, and immediately ascended to the ceiling. Here was 



