Penn Library

John W. Mauchly and the Development of the ENIAC Computer

World War II and the Moore School

Few aspects of life remained untouched by World War II. Even before the attack on Pearl Harbor, the United States had begun to mobilize the nation's scientific and engineering resources, particularly through the work of the National Defense Research Committee (NDRC). But the NDRC was not the only vehicle for science mobilization. At the Moore School change resulted more from the military training programs established for the U.S. Army and Navy and through several secret wartime projects supported by the U.S. Army Ordnance Department's Ballistics Research Laboratory. The Ballistics Research Laboratory (BRL) was charged with producing firing tables in conjunction with the ever-changing field artillery that were being used in the war.* This need had brought the contract for the Moore School differential analyzer, a mechanical analog calculating engine that had preceded the ENIAC work. Such efforts created a demand for additional faculty, and when Mauchly completed his summer training course, he was offered a position as an adjunct instructor.
Page discussing use of differential analyzer in Gilbert Bliss, Mathematics for Exterior Ballistics, 1944. (Van Pelt Library, UP) (click to expand to 55k)

Women at work on Moore School calculating machines during the 1940s. (click to expand to 121k)
The pressing needs of BRL also brought to the Moore School a team of skilled women who operated desk-top calculating machines to produce manually firing tables. Electrical Engineering had traditionally been a male discipline, and the arrival of women raised some waves, particularly among the School's undergraduates. However, these women, some of whom were hired directly by the School and others who were assigned out of the Army's Women's Auxiliary Corps (WACs), were generally older than the students. To make matters worse, many of them already held mathematics degrees. As a contemporary student comic strip, "Moore School Mike" depicts, the self-image of engineers was as much about their awkwardness as their sexual desires. This and material within Mauchly's own papers reveal the very gendered nature of engineering workplaces during World War II.
Much of Mauchly's daily life was occupied with both war research and his teaching duties. He took over some of the basic electrical engineering courses opened up by faculty members who had been reassigned to war research. At the same time, he was assigned to a U.S. Army Signal Corps project to calculate antenna radiation patterns for radar use. In conjunction with this project, Mauchly himself had hired a team of mostly female mathematicians to perform manual calculations. During his private time Mauchly studied cryptography, which also dealt with statistical quantities. All of this work extended his exposure to complicated calculations, which only increased his interests in electronic computation.

Graph by Mauchly depicting letter frequencies
for cryptographical study. (click to expand to 83k)

Detail of a collage depicting the Moore School during WWII, showing Mauchly in classroom. (click to expand to 110k)

* Some pertinent web resources:
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