Joseph Fourier

Joseph Fourier (1768-1830), French mathematician. Jean Baptiste Joseph Fourier was born in Auxerre and educated at the monastery of Saint-Benoît-sur-Loire. He taught (1795) at the École Normale, where he had been a student, and at the École Polytechnique in Paris from 1795 to 1798 when he joined the campaign of Napoleon I in Egypt. After returning to France in 1802 he published important material on Egyptian antiquities and was, until 1815, prefect of Isère Department. He was created a baron by Napoleon in 1808. In 1816 he was elected to the Academy of Sciences and in 1827 to the French Academy. His fame rests on his work in mathematics and mathematical physics. In his treatise The Analytical Theory of Heat (1822; trans. 1878), he employed a trigonometric series, usually called the Fourier series, by means of which periodic functions can be expressed as the sum of an infinite series of sines and cosines.