Poland revived after the I World War and required the knowledge and capabilities of its sons and daughters scattered all over the world. Jan Czochralski did not forget about the native land despite his high position in German industry. He returned to Poland at the invitation of the President of Poland, Ignacy Mościcki, an eminent professor of chemistry, and in 1929 he took the position of professor in the Faculty of Chemistry at the Warsaw University of Technology, where he also obtained one of the first honorary doctorates of this University. He invested the fortune he brought from Germany in Polish indus try and the arts (i.e. founded artistic scholarships). The drawing rooms of his home became popular in Warsaw. Once again he organ ized his workshop: the Department of Metallurgy and Metals Science in the Warsaw University of Technology, and Institute of Metallurgy and Metal Science. The latter mainly was working for the Ministry of Defense. Both of these scientific institutions were equipped with the latest apparatus. Prof. Czochralski also organized the Metallurgical Section of the Chemical Research Institute, one of the leading independent re search institutions in the country.
In the institutions mentioned above, Prof. Czochralski continued the studies which he had undertaken earlier in Germany. He was still engaged in measurements of the rate of crystallization of metals. He also studied the elastic properties of metals and alloys and their corrosion in different gas atmospheres. In addition, Czochralski investigated the influence of experimental conditions on the shape of crystals obtained by his growth method (Wiadomości Instytutu Metalurgii i Metaloznawstwa 3, 69-75 (1936), 4, 85-88 (1937)) and studied another method of obtaining single crystals, by recrystallization of the initial material.
He had fulfilled his pronouncement of youth. He was famous and prosperous, but he also remembered his origin. Jan Czochralski did not forget native Kcynia where his mother lived. In Kcynia he had his second home. He was very interested in everything that concerned his native surroundings. He supported both archeological studies as well as geological search for petroleum beds. He was also interested in the progress of the Polish economy and there are even some papers retained from that period. There is also the term Czochralski process, mentioned in McGraw-Hill Dictionary of Scientific and Technical Terms (3rd edition, p. 408), in the field of ecology.