Joseph Michel Montgolfier (1740-1810) and Jacques Étienne Montgolfier (1745-1799), brothers and French inventors of the montgolfière, the first practical hot air balloon. On December 14, 1782, they succeeded in an outdoor launch of an 18 meter silk bag, which reached an altitude of 250 meters. In their first public demonstration on June 5, 1783, they sent up at Annonay, near Lyon, France, a 900 meter linen bag inflated with hot air. The flight covered 2 kilometers and lasted 10 minutes, reaching an estimated altitude of 1,600 - 2,000 meters. On November 21, 1783, the first free flight by a human was made by Pilâtre de Rozier and Marquis d'Arlandes who flew aloft for 25 minutes about 100 meters above Paris for a distance of 9 kilometers using a Montgolfier balloon. Only one of the Montgolfier brothers ever flew in a balloon, and only once. Hot air balloons were soon surpassed by gas balloons, and did not return to popularity until the 1960s when propane gas became available as a practical fuel.