BOBTELSKY, MORDEKHAI (Max ; 1890–1965), Israel inorganic chemist and pioneer of heterometry, born in Vladislavov (Naumiestis), Lithuania. Bobtelsky taught at Orel and Vitebsk (1916–1922). He worked with Fritz *Haber in Berlin, and then in a large inorganic chemicals factory in Aussig (Usti nad Labem), Czechoslovakia. He went to Palestine in 1925 as chief chemist of Palestine Potash Ltd. and joined Hebrew University, Jerusalem (1927), becoming professor of inorganic and analytical chemistry in 1937. Many of his writings were devoted to heterometry.