Poisson, Siméon Denis (1781–1840)
French mathematician whose main interest lay in the application of mathematics
to physics, especially in electrostatics and magnetism. He developed a two-fluid
theory of electricity and provided theoretical support for the experimental
results of others, notably Charles de Coulomb.
Poisson also made important contributions to mechanics, especially the theory
of elasticity; to optics; to the calculus, especially definite integrals;
to differential geometry; and to probability theory. In all he wrote more
than 300 papers on mathematics, physics, and astronomy, and his Traité
de mécanique (1811) was long a standard work.