COHEN, ERNST JULIUS

COHEN, ERNST JULIUS (1869–1944), Dutch physical chemist. His father, Jacques Cohen, also a chemist, went to Holland from Germany and founded the Netherlands Coal Tar Distillery. Ernst Julius was born in Amsterdam, and became the leading disciple of van't Hoff. From 1902 he was professor of inorganic and general chemistry at Utrecht. He explained the previously mysterious phenomenon of "tin disease" and pursued research on the polymorphism and physical metamorphosis of numerous solid substances, notably iodides. Cohen established the historical committee of the Dutch Chemical Society and its historical library, and the Dutch Society for the History of Medicine, Natural Sciences, and Mathematics. He was the first president of the Dutch Chemical Society, chairman of the Dutch Committee on Coinage, and president of the International Union of Pure and Applied Chemistry. Among his many books are Piezochemie kondensierter Systeme (1919), in collaboration with W. Schut, Physico-Chemical Metamorphosis and Some Problems in Piezochemistry (1926), and textbooks for medical students and on physical chemistry and inorganic chemistry. In 1941 his property was seized by the Germans. Two years later he was arrested and sent to a concentration camp, but released after an appeal by the Dutch Chemical Society. Early in 1944, he was advised to flee the country, but he refused. He was arrested, and transported to the gas chambers of Auschwitz. -BIBLIOGRAPHY: Donnan, in: Journal of the Chemical Society (1947), 1700. (Samuel Aaron Miller)