Becquerel, Alexandre-Edmond 1820-91
French physicist

Born in Paris, he was the son and assistant of Antoine C�sar Becquerel. At 18 he decided to join his father at the Natural History Museum of Paris. In 1852 he was appointed to the chair of physics at the Conservatoire des Arts et M�tiers, taught chemistry at the Soci�t� Chimique de Paris (1860-63), and eventually succeeded his father at the Museum in 1878. His research covered electricity, magnetism and optics. He demonstrated in 1843 that James Joule's law governing heat and electric current applied not only to solids, but also to liquids. He also investigated diamagnetism, the magnetic properties of oxygen, and solar radiation, and constructed the 'actinometer' (an instrument that determined light intensity by measuring electric current) and a phosphoroscope.