Dominik Fransua Arago
Date of Birth: 02/26/1786
Place of birth: Estazhele (Pyrenees-Orientales)
Arago, DOMINIQUE FRANCOIS (Arago, Dominique Fran & # 231; ois Jean) (1786-1853), French physicist, astronomer and politician. Born February 26, 1786 in Estazhele (Pyrenees-Orientales). He studied at the Ecole Polytechnique in Paris. In 1809-1831 - professor of analytic geometry in this school. In 1830 he was appointed director of the Paris Observatory and the permanent secretary of the Paris Academy of Sciences. In 1830-1848 - member of the Chamber of Deputies from okrugaNizhnyaya Sung. After the revolution of 1848 became a member of the interim government, he served as Secretary of the Navy.
Scientific work Arago devoted to magnetism, optics, astronomy. In 1811 he opened the chromatic polarization of light (whether Zh.Bio and D.Bryustera), first observed rotation of the polarization plane of light in quartz. In 1820 he discovered the magnetization of iron filings near a current-carrying conductor (magnetic induction), and in 1824 demonstrated the action of a rotating metal plate on a magnetic needle (rotation magnetism). It establishes a connection between the northern lights and magnetic storms (magnetic field intensity changes of the Earth).
Arago constructed a number of optical instruments, used in astronomy, physics and meteorology: polariscope (1811), ulanometr (a device for measuring the blue of the sky) (1815), a photometer to determine the brightness of stars (1833).
Arago adhered to the wave theory of light and Fresnel in 1838 described experimental scheme to compare the speed of light in air and a dense media - water and glass (delivered in 1850 and A.Fizo L.Fuko). According to the instructions of Arago U.Levere conducted a mathematical analysis of deviations in the motion of the planet Uranus, which resulted in the open - "on the tip of the pen" - the planet Neptune.
Arago died in Paris October 2, 1853.