Differential Analyzer (Mechanical Computer) – Philadelphia PA


In 1934-1935, the Moore School of Electrical Engineering at the University of Pennsylvania built a differential analyzer, an early type of computer. Designed by Oscar Schuck, it was the second of its kind – the first differential analyzer was constructed at the Massachusetts Institute of Technology in 1931. Funds and skilled labor (for example, electricians and instrument makers) came from the Civil Works Administration (CWA) and the Federal Emergency Relief Administration (FERA).

A government report from Pennsylvania described the differential analyzer: “The machine weighs 3-1/2 tons. It is approximately 30 feet long, 10 feet wide and 5 feet high. It contains 37,761 separate parts, in which are included 1,100 complete sets of ball bearings. The Analyzer has ten integrators (the heart and brains of the outfit)—four more than the first machine which was developed at the Massachusetts Institute of Technology. Seven electric motors with intricate wiring and control devices are required” (1934-1935 FERA report).

The differential analyzer was capable of solving complex math problems in just a few minutes – problems that previously would have taken a small team of mathematicians weeks or months to solve. Dr. Charles Fawcett, professor of electrical engineering at the University of Pennsylvania, further explained the machine’s capabilities: “[It] will not only solve various related mathematical equations, but will ‘memorize’ the results, solve other variables in the equation and then reach back in its memory and give accurate answers” (Clarion-News, 1934).

The New Deal-funded differential analyzer was a mechanical, or analog, computer, utilizing “gears, wheels and mechanical amplifying mechanisms” (Clarion-News, 1934), which helped pave the way for the modern digital computer. The success of the differential analyzer “resulted in contract work for various University departments, private companies, and government agencies” (UPenn Archives) and hastened the development of more complex mechanical calculators, electrical computers, and, ultimately, digital computers.

In fact, the Moore School of Engineering at the University of Pennsylvania was a hotbed of early computing technology and subsequently developed the first digital computer, the ENIAC, in 1945.

The differential analyzer built with the help of the New Deal was, in short, a stepping-stone to the machines of the electronic/digital age, “From our smartphones, touch screens, and tiny cameras to our automobiles, airplanes and medical equipment” (UPenn Engineering).

After several inquiries in May 2022, we were unable to determine whether the differential analyzer still exists.  Chances are it does not.

Source notes

Robert D. Leighninger Jr., Long-Range Public Investment: The Forgotten Legacy of the New Deal, Columbia, SC: University of South Carolina Press, 2007, p. 50.

Federal Emergency Relief Administration, The Emergency Work Relief Program of the F.E.R.A., April 1, 1934 to July 1, 1935, 1935, pp. 23 and 25-26.

“Relief Workers Build World’s Largest Calculator,” The Daily Item (Sunbury, Pennsylvania), April 4, 1934, p. 10.

"Three Ton Machine Will Think For 12 Experts," United Press article, in the Chillicothe Constitution-Tribune (Chillicothe, Missouri), July 16, 1934, p. 4.

“Analyzer Solves Problems Which Baffle Experts,” Clarion-News (Opelousas, Louisiana), November 22, 1934, p. 11.

Moore School of Engineering. Office of the Director Records,” University of Pennsylvania, University Archives & Records Center (accessed May 10, 2022).

Celebrating Penn Engineering History: ENIAC,” Penn Engineering, University of Pennsylvania (accessed May 10, 2022).

Moore School Building,” Penn Facilities & Real Estate Services (accessed May 10, 2022).

"ENIAC"  https://en.wikipedia.org/wiki/ENIAC


Project originally submitted by Brent McKee on May 22, 2022.

We welcome contributions of additional information on any New Deal project site.


Location Info

Moore School of Electrical Engineering (former)
Philadelphia PA , PA 19104

Coordinates: 39.952317 , -75.190298

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