**Marcel Brillouin** worked on topics ranging from history of science to the physics of the earth and the atom.

- George Brillouin was born on 22 April 1817 at Saint Jean d'Angély, Charente Maritime, to Louis Brillouin and Marguerite Sorin.
- André Brillouin became an engineer and provided electric light to replace gas lighting.
- Brillouin was able to return to Paris in 1872 and, having spent the intervening time well, excelled at his studies.
- Despite his outstanding mathematical abilities, it was physics that Brillouin concentrated on, perhaps being influenced by Pierre Auguste Bertin (1818-1884) who was a physicist and Deputy Director of the École.
- After graduating from the École Normale, Brillouin was a physics assistant to Eleuthère Elie Nicolas Mascart (1837-1908) at the Collège de France while he worked for his doctorate in mathematics and physics which was awarded in 1881.
- Brillouin's first research publication, published in the Journal de Physique Théorique et Appliquée in 1878, was Liquéfaction des gaz Ⓣ(Gas liquefaction).
- In 1881, Brillouin also published "Du partage des courants instantanés" Ⓣ(Sharing instantaneous currents) in which he states he is a "Doctor of Mathematical Sciences." A major publication in 1882, Comparaison des coefficients d'induction Ⓣ(Comparison of induction coefficients), must also be one of two theses he submitted for his doctorate.
- Mascart was the professor whom Brillouin had worked under at the Collège de France and who had supervised his doctoral studies.
- Léon Brillouin studied at the École Normale Supérieure from 1908 to 1912, then went to the Ludwig Maximilian University of Munich where he studied under Arnold Sommerfeld.
- The Brillouin zones of solid state physics are named for Léon Brillouin.
- Jacques Brillouin became a composer.
- After the papers connected with his thesis, Brillouin published Sur la torsion des prismes Ⓣ(On the torsion of prisms) (1886), Essai sur les lois d'élasticité d'un milieu capable de transmettre des actions en raison inverse du carré de la distance Ⓣ(Essay on the laws of elasticity of a medium capable of transmitting actions in inverse ratio to the square of the distance) (1887), Questions d'hydrodynamique Ⓣ(Hydrodynamic issues ) (1887), Note sur un point de thermodynamique Ⓣ(Note on a point of thermodynamics) (1988), Chaleur spécifique pour une transformation quelconque et thermodynamique Ⓣ(Specific heat for any transformation and thermodynamics) (1888), and Déformations permanentes et Thermodynamique Ⓣ(Permanent deformations and thermodynamics) (1888).
- In 1891 Brillouin published the book Récherches récentes sur diverses questions d'hydrodynamique exposé des travaux de von Helmholtz, Kirchhoff, Sir W Thomson, Lord Rayleigh, etc.
- From 1900 to 1931 Marcel Brillouin was Professor of Mathematical Physics at the Collège de France.
- Brillouin was elected to the Académie des Sciences on 21 November 1921.
- Brillouin wrote around 200 papers on theory and experiment.
- The kinetic theory of matter was enriched by Brillouin's contributions to the theory of diffusion and viscosity in gases and liquids, and he also took part in the once topical controversy on the apparent contradiction in statistical mechanics between the reversibility of the laws of dynamics and the irreversibility of those of thermodynamics.
- Two books by Brillouin, in addition to the one mentioned above, are Propagation de l'Électricité: Histoire et Théorie Ⓣ(Propagation of electricity: history and theory) (1904) and Leçons sur la Viscosité des Liquides et des Gaz Ⓣ(Lessons on viscosity of liquids and gases ) (1906-07).
- Brillouin was friends with most of the top scientists of his day.
- Brillouin died in Paris but was buried in Saint-Martin-lès-Melle, Deux-Sèvres.

Born 19 December 1854, Melle, Deux-Sèvres, France. Died 16 June 1948, Paris, France.

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**O’Connor, John J; Robertson, Edmund F**: MacTutor History of Mathematics Archive