Clerk, Swiss Patent Office, Bern, 1902-1909. Lecturer, University of Bern, 1908. Associate professor of physics, University of Zurich, 1909-1910. Professor of physics, Unversity of Prague, 1911. Professor of physics, Swiss Federal Polytechnic Institute, 1912-1913. Director, Kaiser Wilhelm Physical Institution, Berlin, 1914-1933. Professor of Theoretical Physics, Institute for Advanced Study, Princeton, 1933-1955.