Marcel Brillouin (19.12.1854-16.06.1948) was a French physicist and a member of the Paris Academy of Sciences (1921). He was born in Melle. He graduated from the École Normale (1878). He taught at Nancy, Dijon and Toulouse, and in 1888 —1900 at the École Normale. In 1900 —31 he was professor at the Collège de France.
His research was in many branches of physics: molecular physics, heat, electrodynamics, radiotelegraphy, relativity and others. In particular, in 1900 he developed a mathematical theory of the diffusion of gases, and he studied the viscosity of liquids and gases, the structure of crystals and the stability of the aeroplane.
His pupils included J. Perrin, P. Langevin, L. Brillouin and others.