Editing Montgolfier brothers (section)

===Hot air balloon experiments, 1782===

Of the two brothers, it was Joseph who was first interested in aeronautics; as early as 1775 he built [[parachute]]s, and once jumped from the family house. He first contemplated building machines when he observed laundry drying over a fire incidentally form pockets that billowed upwards.<ref>Gillispie, C. C. ''The Montgolfier brothers and the invention of aviation 1783–1784'', p. 15.</ref> Joseph made his first definitive experiments in November 1782 while living in [[Avignon]]. He reported some years later that he was watching a fire one evening while contemplating one of the great military issues of the day—an assault on the fortress of [[Gibraltar]], which had proved [[Great Siege of Gibraltar|impregnable from both sea and land]].<ref>Gillispie, p. 16.</ref> Joseph mused on the possibility of an air assault using troops lifted by the same force that was lifting the embers from the fire. He believed that the smoke itself was the buoyant part and contained within it a special gas, which he called "Montgolfier Gas", with a special property he called levity, which is why he preferred smoldering fuel.

Joseph then built a box-like chamber {{convert|3|by(x)|3|by(x)| 4|ft|m|1|order=flip}} out of very thin wood, and covered the sides and top with lightweight [[taffeta]] cloth. He crumpled and lit some paper under the bottom of the box. The contraption quickly lifted off its stand and collided with the ceiling.

Joseph recruited his brother to balloon building by writing, "Get in a supply of taffeta and of cordage, quickly, and you will see one of the most astonishing sights in the world." The two brothers built a similar device, three times larger having a volume 27 times greater. On 14 December 1782 they conducted their first test flight, using ignited wool and hay as fuel. The lifting force was so great that they lost control of their craft. The device floated nearly {{convert|2|km|mi|sp=us|spell=in}} but was destroyed after landing by the "indiscretion" of a bypasser.<ref>Gillispie, p. 21.</ref>