Hempel worked at the
Albertina in Vienna until 1931, when he was appointed an
associate professor at the
University of Graz. In 1933, Hempel became a full professor at
Dresden Technical University. In November 1933, he signed the
German Professors' Pledge of Commitment to Adolf Hitler and was charged with the managing of
Cornelius Gurlitt's collection. At this time, he also joined
Der Stahlhelm, though his contingent was merged into the
Sturmabteilung in 1934. ==Bibliography==