Jacques Charles, French aeronaut and physicist, c 1793.
© Science Museum / Science & Society Picture Library
Line and stipple engraving by P G Tavenard. Profesor Charles (1746-1823) discovered Charles's Law, which described the relationship between the expansion of gas and its rise in temperature. In 1783 he made the first flight in a hydrogen- filled balloon. He was accompanied by one of the Roberts brothers, who built the balloon. They flew for 27 miles in the first instance and later set a record by ascending to an estimated 10,000 feet. Profesor of physics in Paris, he invented many scientific instruments.