found: Wikipedia, February 20, 2020(Karl Schaum; Ferdinand Karl Franz Schaum (14 July 1870, Frankfurt am Main--30 January 1947, Giessen) was a German chemist who specialized in the field of photochemistry; he studied mathematics and sciences at the Universities of Basel, Berlin, Leipzig and Marburg, earning his doctorate at the latter institution in 1893; afterwards, he served as an assistant to Theodor Zincke at Marburg and to Wilhelm Ostwald in Leipzig; in 1897 he obtained his habilitation at Marburg with a thesis on types of isometry; in 1904 he became an associate professor of physical chemistry at the University of Marburg, where he was an important influence towards the career of chemist Max Volmer; in 1908 he relocated to the University of Leipzig as an associate professor of photochemistry and scientific photography; from 1914 to 1935 he worked as a full professor of physical chemistry at the University of Giessen)