AIR BALLqONS. 167 



the celebrated Dr. Black, that if a thin bag were filled with 

 this gaseous substance, it would, according to the establish- 

 ed laws of specific gravity, rise in the common atmosphere ; 

 but he did not pursue the inquiry. The same idea was con- 

 ceived by Mr. Cavallo, to whom is generally ascribed the 

 honour of commencing the experiments on this subject. He 

 had made but little progress, however, in these experiments, 

 when the discovery of Stephen and John Montgolfier, paper- 

 manufacturers of France, was announced in 1782, and en- 

 gaged the attention of the philosophical world. Observing 

 the natural ascent of smoke and clouds in the atmosphere, 

 those artists were led to suppose that heated air, if enclosed 

 in a suitable covering, would also prove buoyant. After se- 

 veral smaller experiments, by which this idea was fully con- 

 firmed, they inflated a large balloon with rarefied air, which 

 immediately and rapidly rose to the height of six thousand 

 feet, and answered their most sanguine expectations. 



It was soon found that machines of this kind might be so 

 contrived, as to convey small animals, and even human be- 

 ings, through the air with ease. The first adventurer in this 

 aerial navigation was Pilatre de Rozier, a daring Frenchman, 

 who rose in a large balloon from a garden in the city of Pa- 

 ris, on the 15th of October, 1783, and remained a consider- 

 able time suspended in the air. He made several aerial 

 voyages afterwards of greater extent, and in two of them was 

 attended by other persons. In a short time, however, the use 

 of rarefied air in aerostation was for the most part laid aside, 

 as inconvenient and unsafe. On recurring once more to the 

 discovery of Mr. Cavendish, the philosophers of Paris con- 

 cluded that a balloon, inflated with hydrogen gas, would an- 

 swer all the purposes of that contrived by the Montgolfiers, 

 and would also possess several additional advantages. They 

 made their first experiment in August, 1783, which was at- 

 tended with complete success. Since that time, air-balloons 

 filled with rarefied air have not been generally used. 



The first aerial voyage in England was performed by Vin- 

 cent Lunardi, a native of Italy. The diameter of his bal- 

 loon was thirty-three feet. Soon after, Mr. Blanchard as- 

 cended, carrying up a pigeon, which flew away from the 

 boat, laboured for some time with its wings to sustain itself 

 in the air, and finally returned and rested on one side of the 

 boat. He ascended so high as to experience great difliculty 



