Jacques Alexandre César Charles (12.11.1746—7.04.1823) — French physicist, member of the Paris Academy of Sciences (1803), and its president in 1816. Born in Beaugency. Self-taught. Professor of experimental physics at the Conservatoire des arts et métiers in Paris.
He studied the expansion of gases and established (1787) the law of the change of pressure of a given mass of an ideal gas with temperature at constant volume (Charles's law). Immediately after the brothers J. and E. Montgolfier he built a balloon of rubberised fabric and was the first to use hydrogen to fill it. He made a flight in this balloon in 1783. He invented a number of instruments. He was the first to attempt to obtain photographic images.