Émile Verdet

Marcel Émile Verdet (; 13 March 1824 – 3 June 1866) was a French physicist. He worked in magnetism and optics, editing the works of Augustin-Jean Fresnel. Verdet did much to champion the early theory of the conservation of energy in France through his editorial supervision of the ''Annales de chimie et de physique''.

The Verdet constant is named after him. Provided by Wikipedia