Born Feb. 26, 1786; died Oct. 2,1853, in Paris. French astronomer, physicist, and political figure. Member of the Paris Academy of Sciences from 1809. Studied at the École Polytechnique in Paris. Secretary of the Bureau des Longitudes in Paris since 1805. Professor at the École Polytechnique during 1809–31. Permanent secretary of the Paris Academy of Sciences and director of the Paris Observatory from 1830. Served in the Chamber of Deputies in 1830–48, as a member of the bourgeois republican opposition. After the February Revolution of 1848, joined the Provisional Government as marine minister. Supported suppression of the uprising of June 1848. In 1852 refused to swear an oath of allegiance to Napoleon III.
Arago was an important figure in French science. Upon his instructions, U. Leverrier made a mathematical analysis of the irregularities of the movement of the planet Uranus, which led to the discovery of Neptune, while H. Fizeau and L. Foucault measured the speed of light and obtained the first photograph of the sun. Arago’s main contributions are in astronomy, optics, electromagnetism, and meteorology. He invented the polariscope and studied the polarization of light. He obtained the first artificial magnets from steel. In 1824 he discovered magnetism of rotation, that is, the impact of a rotating metal plate on a magnetic needle, and established the connection between the aurora borealis and magnetic storms.
WORKSOeuvres complètes. . . , vols. 1–3. Edited by M. J.-A. Barral. Paris-Leipzig, 1854–62.
In Russian translation:
Biografii znamenitykh astronomov, fizikov i geometrov, vols. 1–2. S̄t. Petersburg, 1859–61.
Obshcheponiatnaia astronomiia, vols. 1–4. St. Petersburg, 1861.
Izbrannye stat’i iz zapisok Fransua Arago o nauchnykh predmetakh. . ., vols. 1–2. St. Petersburg, 1866.