Monroe Calculating Machine

This full-keyboard, non-printing, manual, modified stepped drum calculating machine has a metal frame painted black, with rounded corners. The eight columns of black and white plastic keys have a red clearance key at the bottom of each column. Rotating rods between the rows of keys serve as decimal markers. Three keys are in a column to the right of the number keys. One clears the entire keyboard. The other two are set to determine whether or not the keyboard clears after each calculation. The operating crank on the right side rotates clockwise for addition and counterclockwise for subtraction.
In back of the keyboard is a carriage that has a row of 16 numeral dials for recording results and a row of eight numeral dials behind these that serves as a revolution register. Digits for the revolution register are red and black. Between the windows for these registers are two thin metal rods that carry decimal markers. The carriage shift lever is at the front of the machine. On the carriage, to the right of the result register, is a lifting knob. A crank on the right of the carriage for zeros registers on it. The machine has four rubber feet.
A mark on the front reads: MONROE. A red tag attached to it reads: PATENT DEPT. (/) #254. A white tag attached to it reads: Monroe Calculator 8 Banks (/) Hand Side Crank (/) #92701 (/) (A. Williamson) (/) Rack B Shelf #3.
This is model #254 from the Patent Division of Burroughs Corporation. Date based on assumption model number is 92701.
Compare to MA*334711, MA*307386, and 1983.0831.1.
J. H. McCarthy, The American Digest of Business Machines, Chicago: American Exchange Service, 1924, p. 551.
Currently not on view
Object Name
calculating machine
date made
Monroe Calculating Machine Company
Physical Description
plastic (overall material)
metal (overall material)
overall: 19.5 cm x 44 cm x 40 cm; 7 11/16 in x 17 5/16 in x 15 3/4 in
place made
United States: New Jersey, Orange
ID Number
catalog number
accession number
See more items in
Medicine and Science: Mathematics
Science & Mathematics
Calculating Machines
Data Source
National Museum of American History, Kenneth E. Behring Center
Credit Line
Gift of Burroughs Corporation
Additional Media

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