Chap. 14.] Diftovery of Montgolfier. 509 



in iefs than ten minutes it reached the height of fir 

 thoufand feet. It was carried in a horizontal di- 

 rection to the diftance of feven thoufand fix hundred 

 and fixty-eight feet, and then defcended gently on the 

 ground. 



The true caufe of the afcent of thefe machines is, 

 the air being rarefied and expanded within them by 

 the application of heat. 



Thefe experiments were no fooner communicated 

 to the philofophers of Paris, than it occurred to them, 

 that as the weight of inflammable air was not more 

 than the eighth or tenth part of that of common air, a 

 balloon might be inflated with this light air, which 

 would anfwer all the purpofes of thofe of M. Mont- 

 golfier, with feveral additional advantages. They 

 conftructed a globe of luteftring, which was made im- 

 pervious to the inclofed air by a varnifh of elaftic gum 

 diffolved in fpirits or eflential oil. On the 2jd of 

 Auguft, 1783, they began to fill a globe of thirteen 

 feet diameter with inflammable air ; on the 27 th of the 

 fame month it was carried to the Champs de Mars, and 

 being difengaged from the cords, it arofe in two mi- 

 nutes to the height of three thoufand one hundred and 

 twenty three feet. When this balloon went up, its 

 weight was thirty- five pounds Iefs than the fame bulk 

 of common air. 



The firft perfon who afcended into the atmofphere 

 in one of thefe machines was M. Pilatre de Rozier. 

 On the I5th of October, 1783, this adventurer went 

 up from a garden in the Fauxbourg St. Antoine in 

 Paris, in a balloon of the Monrgolfier kind, or thofc 

 inflated by heat or rarefied air ; its diameter was about 

 forty-eight feet, and its height about feventy-four ; he 

 afcended from amidft an aftonimed multitude to the 

 height of eighty-four feet from the ground, and there 



kept 



