Hedwig Kohn was a groundbreaking German physicist—both for her work and being a female scientist in the early 1900s—who spent part of her career at Duke.
Hedwig Kohn was a groundbreaking German physicist—both for her work and being a female scientist in the early 1900s—who spent part of her career at Duke.

Before joining the Duke physics department as a research associate in 1952, Hedvig Kohn had to face sexism and flee the Nazis.

A physics department colloquium Wednesday showcased the story of the former Duke physicist and the obstacles she faced as a Jewish female scientist in early 20th century Germany. “The Life and Work of Hedwig Kohn: From the Kaiserreich to the Subbasement of the Duke Physics Building” was presented by Ohio State University physics professor Brenda Winnewisser, Ph.D ’65, to an audience of faculty and students.

“It’s a story of persistence,” said Horst Meyer, Fritz London professor emeritus of physics, Kohn’s friend and former colleague. “Her life was a story of endurance, hard work, kindness and professional competence.”

Kohn was born in Germany in 1887, a time when educational opportunities for upper-middle-class women such as herself were rather limited. Despite this disadvantage, she discovered an affinity for math and science and dedicated herself to the study of physics, seeking out a tutor to complement her secondary schooling with advanced math and science instruction.

In 1907, after completing gymnasium, a German equivalent to high school, Kohn made the decision to enter university in her hometown of Breslau. As an auditor rather than a student, because females were not allowed student status at the time. Winnewisser noted that Kohn’s mother and tutor greatly influenced her pursuit of higher-level physics.

“It was very important that her mother encouraged her in her ambitions, even though it was not an intellectual family,” she said. “Her tutor was a truly inspiring teacher. It’s not too surprising that with this sort of help and training she entered university.”

The year after Kohn started taking university courses, the rules were changed and women were officially allowed to enroll. She began research in emission spectroscopy, observing the metal vapors given off by different flames. She received her doctorate in 1913, and in 1914, she was granted her first university staff position as an unpaid personal assistant to the prominent physicist Otto Lummer. The following year, however, World War I broke out. With many of the department’s men enlisting in the army, Kohn was quickly promoted. She alone took the place of all five of Lummer’s full assistants, running labs and advising students. During the war, she continued her research, and in 1918, she decided to apply for Habilitation, the qualification for a full professorship and for giving formal lectures. Only men, however, were eligible for the position.

“The dean handed her the booklet [of Habilitation requirements] and asked, ‘Does this apply to you, Miss Kohn?’ And she simply looked at it and said, ‘Well, I guess it doesn’t,’” Winnewisser said.

Kohn did not allow this setback to deter her from her research, however. To continue studying the photoelectric effect in gases and vapors, she applied for money from the Kaiser Wilhelm Institute for Physics—the former research home of Albert Einstein. She traveled to Berlin to speak directly with Einstein about her work, and it was ultimately agreed that she would be granted the funds to continue her study. Unfortunately, due to Germany’s economic crisis, several years passed before Kohn received the necessary money. While she waited for her funds, competing researchers proved what she was trying to test, and Kohn was left with what seemed to be limited prospects.

While Kohn was working at the Kaiser Wilhelm Institute, the gender barrier to Habilitation was removed. She successfully applied after contributing to an important reference book by her former mentor, Lummer. In 1930, Kohn became the third woman eligible to lecture and teach, 12 years after her first attempt to do so and 17 years after receiving her doctorate.

But three years later, Hitler took power and Kohn’s years of hard work were suddenly in jeopardy. In April 1933, it was announced that Jews were banned from civil service, including at universities, unless they were granted special exceptions.

That September, Kohn’s permission to teach and lecture was revoked. Kohn nevertheless chose to remain in Germany to stay with her family, taking on a job in the electricity industry.

“She felt she had reasons not to leave,” said Winnewisser. “It was her homeland, her family was there, she didn’t want to abandon them. The director of the [Breslau Physics] Institute told her, ‘Stay here, this nonsense won’t last, I’ll make sure you’re taken care of.’”

In 1938, Kohn realized that Germany was no longer safe for her. Escaping to the United States proved to be quite the difficult task, however. With the help of other physicists, Kohn secured a teaching position that would grant her a visa at the University of North Carolina at Greensboro. In 1940, she escaped Germany, traveling across Asia and the Pacific Ocean to the United States.

After teaching at UNC Greensboro for a year, Kohn began work at Wellesley College in Massachusetts. In 1950, at the age of 63, she decided to retire but realized that her financial situation left her unable to do so. She found a solution in the form of Hertha Sponer, a Duke physicist and fellow German refugee.

Sponer had received her Habilitation shortly before Kohn and came to Duke in 1936. She offered Kohn work as a research associate, sharing her Naval research grant. From 1952 until her death in 1962, Kohn worked at Duke, mentoring students and postdoctoral researchers as well as conducting her own research and becoming a beloved figure in the department.

“She was in the lab all the time, and students loved to work with her,” said Meyer. “She was really an extraordinary human being.”

Though she had only a brief and casual relationship with Kohn, Winnewisser became interested in Kohn years after her death. She has been working on a biography of Kohn that will be published Spring 2014.

Physics professor Roxanne Springer, the faculty host for the presentation, noted that though the difficulties faced by Kohn as a woman in physics are not nearly as prevalent today, they are still present to some degree.

“The situation is vastly, vastly better, but there are still problems,” she said.