Rail Cars, Ice Cream and Eggs

Mary Engle PenningtonWho is this nattily dressed woman, and what is she doing atop a 1910 rail car? She’s not a hobo surely, a train robber or movie heroine?

As a woman,Mary Engle Pennington was something almost as rare in her day—an engineer who rode the rails for thousands of miles researching the proper temperatures for transporting and storing food to prevent spoilage. In the end, Pennington—sometimes ruefully referred to as the Ice Lady—set the U.S. Department of Agriculture regulations for commercial refrigeration.

No one person did more than Pennington to advance the safe handling of food, a fact recognized by her posthumous induction into the Hall of Fame of the American Society of Heating, Refrigerating and Air- Conditioning Engineers (ASHRAE). Joseph Bordogna, the Alfred Fitler Moore Professor of Engineering and former SEAS Dean, accepted the award in her name at the ASHRAE meeting held in Dallas in January 2007. Over the course of the 20th century, refrigeration, this onetime luxury, became an indispensable feature of the American home, and is ranked 10th in the National Science Foundation’s list of greatest engineering achievements.

Mary Engle Pennington was born in 1872 in Nashville, Tennessee, but moved to Philadelphia to be near her mother’s Quaker family. In her early teens, she picked up a book on medical chemistry from a local library and became entranced by the world of things she couldn’t see. If, for example, the world’s invisible oxygen disappeared, she realized, all living things would die.

She entered the Towne Scientific School in 1890 and completed a major in chemistry with minors in zoology and botany, earning a “certificate of proficiency” in 1892, then obtaining a Ph.D. in chemistry in 1895. Interestingly, as a woman at Penn in the late 1800’s, Pennington, who had completed all the work necessary for a bachelor of science degree, received the certificate of proficiency because the Towne Scientific School (now part of SEAS) was then a department of the College, which at the time did not award bachelor degrees to women. However, she was able to go on to earn her Ph.D. from Penn because all Ph.D. degrees were administered by the Department of Philosophy (now the Graduate School of Arts and Sciences), which had been open to women from its inception in 1882.

After post-doctoral research at Penn and Yale, she was named director of the Clinical Laboratory at the Women’s Medical College of Pennsylvania in 1898. Later, at the Philadelphia Bureau of Health, she was in charge of ensuring the safety of milk and dairy products sold in the city.

Bordogna delights in her pragmatic approach to developing regulations: “She conducted public policy that was very wise. When regulations were contemplated on how to prepare ice cream and keep it safe to eat, she first went into the streets, got to know the vendors and showed them slides of the kinds of bacteria that were in their pots. She talked them into boiling their equipment.” When the regulations were later introduced, they met little opposition.

In 1905, Pennington joined the U.S. Department of Agriculture as a bacteriological chemist. Later, she was chosen chief of its Food Research Lab, established following the 1906 Pure Food and Drug Act. There, she promulgated her wide-ranging regulations on food handling, based on solid, empirical research. In 1922, after a short stint with a commercial maker of refrigeration insulation, she started her own consulting firm, which she ran until 1952, the year before her death.

Along the way, she was awarded the Notable Service Medal from President Herbert Hoover in 1919 and the Francis P. Garvan medal—the highest award to women—from the American Chemical Society in 1940. “She was a real engineer,” says Bordogna, “in the sense that she put new knowledge to beneficent use in everything she did. Great engineers get their ideas into practice when they have a talent for influencing people about what they’re trying to do. She’s an example of that. I don’t think you can go through a career like hers unless you can interact well with people.”

Today, we benefit in big ways and little from Pennington’s attention to detail. “I get a kick out of knowing that she also invented the precursor to the clever egg cartons we buy our eggs in today,” adds Bordogna.

Credit: Penn Engineering Magazine, “Rail Cars, Ice Cream and Eggs,” by Derek Davis.

Interested? Learn more!

Mary Engle Pennington in the National Women’s Hall of Fame
Women at Penn: Distinguished early graduates, faculty, and benefactors of the University

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