French physicist (1892–1987) known for his theory that matter has the properties of both particles and waves. Untranslated TLS in French, signed “Broglie,” one page, 8 x 10.5, personal letterhead, November 17, 1936. Letter to the secretary general. In very good condition, with central horizontal and vertical folds, scattered creases, staple hole to top left, and uniform toning. RR Auction COA.