 Complete the following phrase:  Cauer initially specialised in general relativity but soon switched to electrical engineering. His work for a German subsidiary of the Bell Telephone Company brought him into contact with leading American engineers in the field of filters. This proved useful when Cauer was unable to feed his children during the German economic crisis of the 1920s and he moved to the US. He studied early computer techniques in the US prior to returning to Germany. According to Wilhelm Cauers son Emil the rise of Nazism in Germany stifled Cauers career because he had a remote Jewish ancestor. Cauer was murdered during the 