Jean Cabannes, French physicist and academic (d. 1959)
Jean Cabannes (born in Marseille on 12 August 1885; died in Saint-Cyr-sur-Mer on 31 October 1959) was a French physicist specialising in optics.

From 1910 to 1914 Cabannes worked in the laboratory of Charles Fabry in Marseille on the topic launched by Lord Rayleigh at the end of the 19th century of how gas molecules diffused light. In 1914 he showed that pure gases could scatter light. This was published in Comptes Rendus in 1915. (Please see reference.) His career was then interrupted for five years by World War I.

In 1919 Cabannes returned to Fabry's laboratory to complete his thesis, after which he moved to Montpellier, and later on to Paris. In 1925 he and Jean Dufay calculated the height of the ozone layer. J. Cabannes, P. Daure and Y. Rocard were among the scientists who, in 1928, discovered that gases diffusing monochromatic light could also change their wavelength (the Cabannes-Daure effect).

This was identified independently by C. V. Raman and K. S. Krishnan in liquids, and by G. S. Landsberg and L. I. Mandelstam in crystals. Cabannes was among the candidates for the Nobel Prize in Physics of 1929 (proposed by C. Fabry), which was awarded to de Broglie.

The 1930 prize went to Raman who gave the complete explanation of the effect now bearing his name, using quantum mechanics.

The lunar crater Cabannes was named after him.

In 1949 he was elected a member of l'Académie des Sciences. In 1924 he received the Prix Félix Robin and in 1951 the first ever awarded Prix des Trois Physiciens from the Fondation de France.

Cabannes was the President of the Société astronomique de France (SAF), the French astronomical society, from 1951-1953.He was married to a daughter of Eugène Fabry (1856–1944), brother of Charles Fabry, and was the father of four children, among whom was the mathematician Henri Cabannes.