Siméon-Denis Poisson

Born on 21 June 1781 in Pithiviers, France, Siméon-Denis Poisson was a mathematician whose research advanced the study of electricity, mechanics, and other areas of physical science. Poisson was apprenticed by his father to an uncle who was a surgeon. It didn’t take long for Poisson to realize that he much preferred mathematics over medicine. In 1798 he entered Paris’s École Polytechnique, where he studied under Pierre-Simon Laplace and Joseph-Louis Lagrange . After attaining his degree in mathematics two years later, Poisson was appointed répétiteur at the school and quickly rose to the rank of professor. Besides his professorship, Poisson took on a number of other educational posts, including chair of mechanics in the newly formed Faculty of Sciences in 1809. He also devoted considerable time to research. Over his career he published more than 300 scientific papers, not only in the field of pure mathematics, on such topics as definite integrals and Fourier analysis, but also in the application of mathematics to physics, particularly mechanics (including celestial mechanics) and electrostatics. In addition he made significant contributions to the study of probability and statistics. His 1837 treatise on the deliberations of juries introduced the Poisson distribution, which describes the probability of a random event occurring in a fixed interval of time or space. Other concepts to which his name has been associated include Poisson brackets in differential equations, Poisson’s constant in electricity, Poisson’s equation in potential theory, Poisson’s integral, and Poisson’s ratio in elasticity.

Date in History: 21 June 1781