 He published a number of studies on Slavic languages, countries and people, as well as translations of important Slavic works of literature, and was a pioneer in opening the field of study of Slavic peoples in the U.S. beyond the dominance of Russian studies of the times.Clarence received his bachelor's degree at the Columbia University in 1912 and master's in 1913.During First World War, he worked in the intelligence police corps of the translation section of the Military Intelligence Division, having rank of sergeant.