4-64. Émile Picard

Charles Émile Picard (1856–1941) was the son of a silk-factory manager. He attended the École normale supérieure (ENS), and obtained both the agrégation in mathematics and a job as agrégé préparateur in mathematics at the ENS in 1877. He was recruited by the Paris Faculty of Science in 1878, and named Chargé de cours in differential and integral calculus at the Faculty of Science in Toulouse the following year. In 1881, he married into academic royalty, by wedding Augustine Hermite, daughter of Charles Hermite, and niece of Joseph Bertrand, then Permanent Secretary of the Paris Academy of Science and a future member of the Académie française. Picard was to hold both these positions, in 1917 and 1924, respectively. Augustine and Émile moved in with the Hermites, and lived under the same roof until 1901. They had five children, and their eldest, Louise, married the normalien physicist Louis Dunoyer de Segonzac in 1906.

Also in 1881, Picard was named suppléant to Bouquet at the Paris Faculty of Science for “mechanical and experimental physics”. He later held concurrent suppléant teaching posts under Appell at the ENS in mechanics and astronomy (1883–1885), and under Bouquet in calculus (1885–1886).

In 1886, Picard was named to the Sorbonne chair of differential and integral calculus, in succession to Bouquet. Picard also lectured on mechanics at the École centrale des arts et manufactures from 1894. In 1897, upon the retirement of his father-in-law, Picard was named to the chair of higher analysis, which he held until his own retirement in 1931. From 1900, he also taught at the École normale supérieure de jeunes filles, in Sèvres.

Picard joined Poincaré in the geometry section of the Paris Academy of Sciences on 11 November, 1889, and succeeded him as a member of the Bureau of Longitudes representing the Academy of Science on 25 November, 1912. Picard served as editor of the works of Hermite (Picard, 1905, 1908, 1912, 1917) and co-editor of Halphen’s works (Jordan et al., 1916, 1918, 1921, 1924). From 2 April, 1917, Picard served as Perpetual Secretary of the Academy of Science, and was elected to the Académie française in 1924, as mentioned above.

Picard’s work, excluding marginalia, is reproduced in four volumes (Leray et al., 1978, 1979, 1980, 1981). Bibliographical and biographical elements are found in Lebon (1910), Broglie (1943), Garnier (1956), Institut de France (1968, 436), Félix (1974) and Charle and Telkes (1989, 226).