Jacques-Philippe-Marie Binet

French mathematician and astronomer, b. at Rennes, in Brittany, 2 February, 1786; d. in Paris, 12 May, 1856. After two years of study at the Ecole Polytechnique, he was appointed, in 1806, student-engineer in the government department of bridges and roads. Teaching, however, soon attracted him. For some time, he was professor of mathematics at the Lycée Napoléon. He then became, at the Ecole Polytechnique, successively, répétiteur of descriptive geometry, examiner, professor of mechanics, and inspecteur-général of studies. In 1823, he succeeded Delambre in the chair of astronomy at the Collège de France. Because of his intense devotion to the cause of Charles X, the Government of July, 1830, removed him from the Ecole Polytechnique, although it allowed him to retain his professorship at the Collège de France. He had been made a member of the Société Philomathique, in 1812. In 1843, he was elected to succeed Lacroix in the Académie des Sciences, of which he was a most active member and had become president at the time of his death. Binet was a man of modest manner and a devout Catholic.

To mathematics, mechanics, and astronomy, Binet contributed many valuable articles on a great variety of topics. These articles were published in the "Bulletins de la Société philomathique", in the "Comptes rendus de l'Académie des sciences", in the "Journal des Mathématiques" (Liouville) and, chiefly, in the "Journal de l'Ecole polytechnique". He also rewrote, to a large extent, the second volume of the "Mécanique analytique" of Lagrange for the edition of 1816. A few of his principal articles are: "Mémoire sur la théorie des axes conjugués et des moments d'inertie des corps", enunciating the principle sometimes called Binet's Theorem (Journ. de l'Ec. pol., IX, 1813); "Mémoire sur la détermination analytique d'une sphère tangente à quatre autres sphères (ibid., X, 1815); "Mémoire sur la détermination des orbites des planètes et des comètes" (ibid., XIII, 1831); "Mémoire sur les intégrales définies eulériennes et sur leur application à la théorie des suites ainsi qu'à l'évaluation des fonctions des grands nombres" (ibid., XVI, 1839; Paris, 1840); "Mémoire sur les inégalités séculaires du mouvement des planètes" (Journal de Math., V, 1840); "Mémoire sur la formation d'une classe très étendue d'équations réciproques renfermant un nombre quelconque de variables" (Paris, 1843).

Comptes rendus de l'Académie de sciences; Journal de l'Ecole polytechnique.

Paul H. Linehan.