who had been thrown out of the Kuratorium already before its dissolution, broke ties to PTR/PTB. Under Stark and – after 1939 – under his successor Abraham Esau, the PTR strongly dedicated itself to armament research. A newly founded laboratory for acoustics was not only to investigate general – but mainly also military – fields of application. This included, among other things, the acoustic finding of artillery, the military utilization of ultrasound and the development of decoding procedures. In addition, researchers of PTR developed acoustic mines and a steering system for torpedoes which orientated itself on the sound field of traveling ships. Due to its classical metrological tasks, the PTR was also closely connected with the armament industry of the Third Reich. Since exact measures are a basic requirement for the manufacture of military equipment, the PTR gained a key role in armament production and defense. The extent to which the PTR was also involved in the German nuclear weapons project is controversial. It is, however, known that – prior to his time as PTR president – Abraham Esau conducted – until 1939 – a group of researchers dealing with nuclear fission. Later, he took over the specialist area "nuclear fission" in the Reich Research Council which supervised, from spring 1942 on, the German uranium project. Shortly after that, Hermann Göring subordinated the working group under the former PTR physicist Kurt Diebner to Division V for atomic physics at the PTR. Esau received the title "Authorized Representative of the Reichsmarschall for Nuclear Physics", a post which he, however, ceded to Walther Gerlach already at the end of 1943. To escape the bombing raids of the allies, the PTR was, in 1943, relocated at the initiative of the president and Thuringian privy councillor Abraham Esau to different places in Germany (for example to Weida and Ronneburg in Thuringia and to Bad Warmbrunn in Lower Silesia). During the attacks on Berlin, the buildings of the PTR were heavily damaged. In 1945, the Reichsanstalt was virtually destroyed and the few departments which still existed were scattered all over the country. Re-founding of PTB in Braunschweig and other PTR successors Approximately from 1947 on, successor institutes were developed in addition to the PTR in Berlin-Charlottenburg, i.e. one in East Berlin – for the Soviet Occupation Zone – and one in the Bizone – and later Trizone. With the well-meaning support of the British Military