French physicist (1870–1942) who won the 1926 Nobel Prize in Physics “for his work on the discontinuous structure of matter, and especially for his discovery of sedimentation equilibrium.” TLS, one page, 8.25 x 10.5, Faculté des Sciences de Paris letterhead, January 22, 1935. An untranslated letter mentioning the Conseil Supérieur de la Recherche Scientifique. Perrin has also added a handwritten postscript. Intersecting mailing folds (vertical fold to “P”) and light handling wear, otherwise fine condition. R&R COA.