Jean-Francois Pilatre de Rozier (1754-1785), French balloonist, blowing hydrogen into a flame, causing the flammable gas to ignite. Hydrogen was one of the gases used in balloon ascents. Rozier is famous for being on the first manned hot air balloon flight in October 1783. He also ascended on other balloon flights, including one in 1784. His final flight was on 15 June 1785, when he and Romain crashed in their Royal Balloon near Boulogne, France. Both men were killed in the crash, which is considered the world's first aerial disaster.