Line and stipple engraving. 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 (over 3,000 metres). Profesor of Physics in Paris, Charles invented several scientific instruments. From the Penn-Gaskell Collection at the Science Museum, London.
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