Becquerel, Jean Antoine Edmond Marie (X 1897 ; 1878-1953)

General Engineer of Bridges and Roads (Ponts-et-Chaussées). Professor at the National Museum of Natural History (1909) where before him three generations of Becquerel had already passed. His scientific work mainly concerns magneto-optics: he creates a new science, the optics of very low temperatures, and his studies on the magnetic rotary power allow him to discover the action of the crystal field, as well as a new phenomenon, metamagnetism. Assistant physics repeater at the École Polytechnique from 1911 to 1919, holder from 1919 to 1924, he was an examiner of students from 1924 to 1948. Like his ancestors, he was a member of the Academy of Sciences (1946)