Siméon Denis Poisson

Baron Siméon Denis Poisson was a French mathematician and physicist, born in 1781 and dying in 1840, who worked on statistics, complex analysis, partial differential equations, the calculus of variations, analytical mechanics, electricity and magnetism, thermodynamics, elasticity and fluid mechanics. He predicted the Arago spot in an attempt to disprove the wave theory of Augustin-Jean Fresnel. At seventeen he entered the École Polytechnique in 1798 after scoring first in its highly competitive entrance examination, and Joseph-Louis Lagrange recognised his talent early and became his friend. He became deputy professor in 1802 and full professor in 1806, succeeding Fourier, a member of the Institute in 1812, and geometer to the Bureau des Longitudes in 1827, succeeding Laplace.