Julius Ferdinand Ruska (9 January1867, Bühl- 11 February1949 Schramberg) was a German orientalist, historian of science and educator. He was a critical scholar of alchemical literature, and of Islamic science, raising many issues on attributions and sources of the texts, and providing translations. The range of his studies was wide, including the Emerald Tablet, a basic hermetic text. From 1924 he headed an institute in Heidelberg, where he has been a student. Of his seven children, Ernst Ruska and Helmut Ruska were distinguished in their fields.
