In the winter of 1939, at the beginning of the World War II, at the request of his coworkers at his institute, Jan Czochralski organized the Depart ment of Materials Research as a service institution. At the price of producing spare parts for the Germans and the city self-government administration, the service institution provided job and security (giving appropriate documents) to dozens of persons in occupied Warsaw. It also supplied the National Army fighting for the freedom of the country.
Cooperation with the National Army (for example, extracting persons imprisoned by the Germans, helping the Jewish ghetto in Warsaw, saving collections of destroyed museums, and rendering help to Polish men of letters and artists) was the natural feature of the activities of Czochralski. He considered it his moral duty to use his German connections and a good knowledge of the German language for the Polish cause, risking both being imprisoned by the Germans and/or being suspected of collaboration. And indeed after the war, the senate of Warsaw University of Technology accused him of collaboration with the Germans and turned down his offer to continue the research, excluding him in this way from the scientific life of the country. This was the price paid by Czochralski for his wish to serve his Motherland.