Werner Heisenberg foundation of the matrix formulation of quantum mechanics through only the use of observables. In February 1943, Heisenberg was appointed to the Chair for Theoretical Physics at the "Friedrich-Wilhelms-Universität" (today, the Humboldt-Universität zu Berlin). In April, his election to the "Preußische Akademie der Wissenschaften" (Prussian Academy of Sciences) was approved. That same month, he moved his family to their retreat in as Allied bombing increased in Berlin. In the summer, he dispatched the first of his staff at the "Kaiser-Wilhelm Institut für Physik" to Hechingen and its neighboring town of Haigerloch, on the edge of the Black Forest, for the
Institute of Physics when the expansion of access to universities removed demand. In 1960, the Physical Society and the Institute of Physics merged, creating a single organization with the unwieldy name "The Institute of Physics and the Physical Society", which combined the learned society tradition of the Physical Society with the professional body tradition of the Institute of Physics. Under the leadership of Thomas E. Nevin an Irish branch of the Institute of Physics was formed in 1964. Upon being granted a royal charter in 1970, the organization was renamed as the Institute of Physics. There are four grades of membership: Associate Member,