Les Frères Robert were two French brothers. Anne-Jean Robert (1758–1820) and Nicolas-Louis Robert (1760–1820) were the engineers who built the world's first hydrogen balloon for professor Jacques Charles, which flew from central Paris on 27 August 1783. They went on to build the world's first manned hydrogen balloon, and on 1 December 1783 Nicolas-Louis accompanied Jacques Charles on a 2-hour, 5-minute flight. Their barometer and thermometer made it the first balloon flight to provide meteorological measurements of the atmosphere above the Earth's surface.

Tiberius Cavallo was an Italian physicist and natural philosopher. His interests included electricity, the development of scientific instruments, the nature of "airs", and ballooning. He became both a Member of the Royal Academy of Sciences in Naples, and a Fellow of the Royal Society of London in 1779. Between 1780 and 1792, he presented the Royal Society's Bakerian Lecture thirteen times in succession.