I Bernard Cohen ’37, a Harvard professor who founded the Department of the History and Science in 1966, died June 20 at his home in Waltham, Mass. He was 89.

He had been suffering from myoplasia, a condition that required a weekly transfusion, according to Professor of the History of Science Everett I. Mendelsohn.

Cohen, who was the Victor S. Thomas Professor of the History of Science Emeritus, “came to Harvard at a critical time…when the natural science courses wanted to use a case study approach which intimately involved the history of science,” said Research Professor of Astronomy and History of Science Owen Gingerich.

In the 1960s, the Committee on Higher Degrees in History of Science and Learning, established four decades earlier by Cohen’s mentor Georges Sarton, became the History of Science department. Cohen was the department’s first chair.

Under Cohen’s leadership, Gingerich said, Harvard became the nation’s largest producer of science historians and triggered the population of other departments throughout the country.

“That Harvard has the flagship history of science program is owing to his magnetic presence,” he said. “He played an important role nationally and internationally in the professionalization of [the field].”

Born in 1914 in New York City, Cohen graduated high school at the early age of 15.

In 1942, five years after earning his degree, he began teaching at Harvard.

According to Gingerich, Cohen’s full-year Natural Sciences 3 course, “The Nature and Growth of the Physical Sciences,” regularly attracted 350 students.

“He was a great showman,” said Gingerich, who served as a teaching fellow for Cohen. “His particular mix of demonstrations and the way he exuded authority in his teaching was very electrifying to lots and lots of students.”

Mendelsohn recalled a class demonstration in which Cohen would send a brass ball on a wire swinging between two teaching fellows, showing the periodicity of a pendulum.

“If he and we didn’t have confidence [in each other], one of us could’ve ended up with a very smashed face,” Mendelsohn said.

Described by Mendelsohn as a “meticulous scholar,” Cohen’s work covered diverse topics including the growth of physics in the 17th and 18th centuries, the relationship between the natural and social sciences, and the history of computing. According to Gingerich, he also played a critical role in putting together the Collection of Historical Scientific Instruments at Harvard, which is located in the basement of the Science Center.

But Cohen considered his most important work to be his 1999 translation of Newton’s Principia Mathematica, which was a collaboration with the late Anne Whitman ’59 and took 15 years to complete.

“During that time, everyone knew he was working on it,” Gingerich said.

Cohen’s is the first English translation of the work since 1729.

Cohen remained at Harvard until his retirement in 1984.

A memorial service will be held on July 3 at 1 p.m. at the Follen Community Church in Lexington, Mass.

—Staff writer Ryan J. Kuo can be reached at kuo@fas.harvard.edu.