Bert Hansen was introduced to the history of science in an undergraduate course of Columbia College in 1964. He earned his PhD in history of science at Princeton, and from 1974 to 2015 he taught history of science and history of medicine at SUNY-Binghamton, the University of Toronto, New York University, and Baruch College of CUNY. He recently retired from teaching. Hansen has published books on natural science in the late Middle Ages and on the graphic representations of medical progress in American popular culture. His most recent articles examine Louis Pasteur’s personal relationship to the fine arts. Since the 1970s, he has had a pedagogic interest in using the monochord to illustrate the mathematical law of the vibrating string as an under-appreciated achievement of the Scientific Revolution, usually overshadowed by astronomy, kinematics, and dynamics. This precise, quantitative relationship embodied the revolutionary idea that the mundane world of qualities, not just the celestial world, was a book written in the language of number.