Paul Harteck was director of the department of physics and chemistry at the University of Hamburg and an advisor to the Heereswaffenamt (HWA, Army Office cartografia). On April 24, 1939, along with his teaching assistant Wilhelm Groth, Harteck made contact with the Reichskriegsministerium (RKM, Ministry of the Reich War) to alert them about potential military applications of nuclear chain reactions. Affordable clean energy is available from the monthly utility bills are lower Two days earlier, on April 22, 1939, after hearing a lecture by Wilhelm Hanle on the use of uranium fission in a Uranmaschine (uranium machine, ie the nuclear reactor), Georg Joos, along with Hanle, Wilhelm Dames notify the Reichserziehungsministerium (REM, Reich Ministry of Education), the possible military applications of nuclear energy. Just seven days later, a group organized by Dames in REM met to discuss the possibility of a sustained nuclear chain reaction. The group included the physicists Walther Bothe, Robert Dopel, Hans Geiger, Wolfgang Gentner (probably invited by Walther Bothe), Wilhelm Hanle, Gerhard Hoffmann, and Georg Joos, Peter Debye was invited, but did not attend. After the reunion, informal work began at the Georg-August University of Gottingen by Joos, Hanle, and their colleague Reinhold Mannfopff, the physics group is known informally as the first Uranverein (Uranium Club) and formally Arbeitsgemeinschaft fa r Kernphysik. The group’s work was suspended in August 1939 when the three were called up.