born Jan. 22, 1775, Lyon, France
died June 10, 1836, Marseille
French physicist, founder of the science of electromagnetism.
A prodigy who mastered the entire known field of mathematics by age 12, he became a professor of physics, chemistry, and mathematics. He formulated a law of electromagnetism, called Ampère's law , that describes the magnetic force between two electric currents. An instrument he devised to measure the flow of electricity was later refined as the galvanometer . His chief published work was Memoir on the Mathematical Theory of Electrodynamic Phenomena (1827). The ampere (A) unit of electric current was named for him.