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MADAS VII T Mechanical Calculator

Physics · L.E. Jones

A sturdy rectangular calculating instrument with a removable metal cover. 

Removing the cover reveals an angled faceplate consisting of several parts. At the top of the faceplate is a sliding register that can be adjusted using two levers at the top left. The register displays two rows of digits. Below each digit is a knob that can be used to change the displayed value.

Below the sliding register is a keyboard with nine vertical rows of keys. Each row has numerical keys from one to nine. To the left of the keyboard is a rotating crank that is used to manually operate the instrument. This knob can be replaced with a button (stored inside the lid) that is used when the instrument is operated using its integrated electric motor.

The motor is located at the lower left of the instrument’s rear. A covered belt along the right hand side of the instrument links the motor to the calculating mechanism.

The metal cover of the instrument includes a rounded protrusion on its front surface to accommodate the protruding crank. A cardboard label is fixed to the inside surface of the lid. This includes instructions for safely using the instrument.

Accession Number:

Alternative Name:

Primary Materials: Iron Alloy, Copper Alloy


Circular label in instrument lid: “Multiplication Automat.Division Addition Subtraction// MADAS”
Damaged label on from cover: “PROPERTY OF UNIVERSITY OF TORONTO”
Label at the upper-right of the sliding register: “SOLD AND SERVICED BY// M. P. HOFSTETTER// TORONTO, ONTARIO”
Metal label at the lower left of the faceplate: “H.W. EGLI Ste Ar[??]// Calculating Machines// ZURICH (Switzerland)”
Engraved at lower left of instrument: “No. 11882// SEULS FABRICANTS// H.W. EGLI S.A.// ZURICH – SUISSE// MADE IN SWITZERLAND// INDUSTRIE SUISSE”.

Dimensions (cm): Height = 25; Width =55; Length = 35.


This is an mechanical calculating instrument using the “stepped drum” mechanism. It is capable of addition, subtraction, multiplication, and division. The instrument has an optional electrical drive that can be used to automate aspects of its operation.


This instrument has various dents, marks, and signs of wear. It is functional using the hand crank but the motor does not work. One electrical contact, connected to the electrical motor at the rear of the instrument, has become detached. Two keys at the lower left of the keyboard are missing. The black paint is especially chipped around the belt cover at the right of the instrument. The paint is worn along the left side of the face plate where the operator gripped the instrument.

Associated Instruments:

Manufacturer: H. W. Egli, Zurich, Switzerland

Date of Manufacture: c. 1940s


This instrument was purchased for Calvin Gotleib, PhD (1921 – 2016), during his doctoral studies at the University of Toronto. It was likely used during Gotleib’s work at the University of Toronto on the development of proximity fusing for antiaircraft shells during the Second World War.

The instrument was donated by Patrick Finnigan to the IHPST on January 11, 2022.

Additional Information and References:

Michael R. Williams. “UTEC and Ferut: The University of Toronto’s Computation Centre,IEEE Annals of the History of Computing, Vol. 16, No. 2, 1994.

University of Toronto Archives and Records Management Services (UTARMS) “Calvin C. Gotlieb Personal Papers” B2002-0003.

The provenance information regarding the use of this instrument in the development of proximity fuses during the Second World War noted above was provided by Calvin Gotleib to Patrick Finnigan during an IEEE awards ceremony.

Historical Notes:

Calvin (“Kelly”) Gotlieb was an instrumental figure in founding the University of Toronto in the years following the Second World War.

The following passage, describing his wartime research work, appears in a letter 1948 letter from Gotlieb to the Department of Labour (UTARMS Calvin C. Gotlieb Personal Papers B2002-0003)

After receiving my B.A. in June, 1942, I joined a group under [U of T] Professor [Arnold] Pitt working on the proximity fuse development in parallel with a similar project being carried out in the United States.

In June of 1943, in answer to a request from the British Admiralty for technical personnel on American proximity fuse techniques, I went to England.

From June to October, 1943, I was engaged in research at A. D. R. D. E. [Air Defence Research and Development Establishment, then named Radar Research and Development Establishment], Malvern, Worcestershire, and in October, I joined a group working with Mr. A.F.H. Thompson at the University of Bristol.

I returned to Canada in February, 1944, and shortly after, started research work on a radio method of measuring the Yaw [of a] shell along with Messrs. P. E. Pashler and M. Rubinoff. This continued as a project administered by the National Research Council of Canada and later by C. A. R. D. E. [Canadian Armament Research and Development Establishment] under the Defence Research Board. A joint paper on this research first appeared in the Canadian Journal of Research, A, 26: 167-198, May, 1948.  

This instrument was therefor likely used during either or both stages of Gotlieb’s wartime research at the University of Toronto.

[Williams 1994, 4] notes that “While the concept of the proximity fuse originated elsewhere, a great deal of work was done at the University of Toronto on both the radio frequency oscillators and the battery systems that were needed.” and that “After the war was over, many of the scientists involved in these projects used this experience to very good effect: the older ones to push for new, computational directions in scientific work, and the younger ones to complete their own postgraduate programs.”

Note also that Gotlieb completed a physics PhD thesis entitled “Problems Connected with the Trajectory of a Yawing Shell” in 1947. 

  • Donated to UTSIC