Hedwig Kohn (5 April 1887 – 26 November 1964) was a physicist who was one of only three women (along Lise Meitner and Hertha Sponer) to obtain habilitation (the qualification for university teaching) in physics in Germany before World War II. Born in Breslau in the German Empire (now Wrocław, Poland), she was forced to leave Germany during the Nazi regime because she was Jewish. She continued her academic career in the United States, where she settled for the rest of her life. Biography Early life Born in Breslau (now Wrocław, Poland), Kohn was the daughter of Georg Kohn, a wholesale merchant of fine cloth, and Helene Hancke, a member of a well-to-do family. Her parents were both German Jews. In 1907, Kohn enrolled in Breslau University (Universität Breslau, now University of Wrocław), a year before women were officially allowed to matriculate. She became the second woman to enter the physics department. She obtained her doctorate in physics under Otto Lummer in 1913 and was soon appointed as Lummer's assistant. She stayed at the university's Physics Institute during World War I, teaching and advising doctoral students in spite of her youth, even receiving a medal for this service after the war. She obtained her habilitation in 1930. Kohn was trained by Lummer in the quantitative determination of the intensity of light, both from broad-band sources, such as a "black body", and from the discrete emission lines of atoms and molecules. Escape from Germany Kohn was dismissed from her position in 1933 due to Nazi regulations which barred Jews from government service (the Law for the Restoration of the Professional Civil Service). In 1935, thanks to US funding, she was able to spend three months at the Licht-Klimatisches Observatory in Arosa, Switzerland, to measure the intensity of ultraviolet rays in the sun. However, this visit did not develop a permanent work. She survived by fulfilling contracts for applied research in the illumination industry until 1938, when she found herself without work or financial resources, and narrowly avoided becoming a victim of the Holocaust. Her only brother was deported to Kovno and murdered. Although a good and respected physicist, she was not internationally famous. The hurdles to her obtaining a job offer out of Germany were enhanced by the lack of university positions in western countries during the Great Depression, her German nationality, her age and being a woman. In some cases,