Franz Ernst Neumann

Born Sept. 11, 1798, in Joachimsthal, Uckermark; died May 23, 1895, in Königsberg (present-day Kaliningrad, USSR). German physicist. Member of the Berlin Academy of Sciences (1858) and corresponding member of the St. Petersburg Academy of Sciences (1838). Professor at the University of Königsberg (from 1828).

Neumann’s principal works were in mathematical physics, optics, electrodynamics, and crystal physics. Between 1845 and 1847 he constructed the theory of electromagnetic induction, in which he derived the first mathematical expression for the law of electromagnetic induction. Neumann investigated the phenomena of reflection, refraction, and birefringence of light. He proposed the theory of elastic properties of crystals and established the relation between the symmetry of the physical properties of a crystal and the symmetry of the physical properties of a crystal and the symmetry of the crystal’s external form (Neumann’s principle).