Monroe Model 213-11-011 Adding Machine

This machine incorporates ideas of Purdue University graduate Clyde Gardner (1881-1923) who had a long career in the adding machine industry. He began as a draftsman at the Pike Adding Machine Company in 1903. By 1909, when Pike was acquired by the Burroughs Adding Machine Company, Gardner was chief engineer. He moved with the Pike plant to Detroit, where he worked as an engineer and patent expert at Burroughs.
In 1919 Gardner left Burroughs to work on his own design for an adding machine. On April 19, 1923, the Gardner Calculator Company was established in Ebensburg, Pennsylvania. Gardner died only two days later. His patents eventurally were acquired by the Monroe Calculating Machine Company, which manufactured this printing adding machine to complement its line of calculating machines.
The object has a green-black steel frame, a green keyboard, and 13 columns of black and white color-coded plastic number keys. To the right of the keyboard are total, error, and subtotal keys, and subtraction and addition bars. A non-add key is to the left of the keyboard. In back of the keyboard is a printing mechanism and a fixed carriage for the three-inch paper tape. The machine prints results of up to 14 digits. An asterisk printed next to a number indicates that it is a total. There is a black rubber-covered cord that plugs into the back.
The machine is marked on the front: MONROE (/) REGISTERED TRADE MARK. It is marked on a white sticker on the bottom of the machine: DATE (/) INSTALLED 10/Apr/57. It is marked on a gold sticker on the bottom of the machine: Licensed under Gubelman Patents. It is also marked there: 213-11-011-D (/) # 15128. According to the National Office Machine Blue Book, the serial number dates a Monroe machine to about 1932.
American Office Machines Service vol. 3, 1937, 3.21. According to this source, the machine was introduced as the Gardner adding machine in 1924.
National Office Machine Blue Book, May, 1975, as compiled by Office Machine Americana, January 2002.
John E. Gable, History of Cambria County, Pennsylvania, Topeka, Kansas: Historical Publishing Company, 1926, pp. 781-782.
Currently not on view
date made
Monroe Calculating Machine Company
place made
United States: New Jersey, Orange
Physical Description
paper (overall material)
cloth (overall material)
plastic (overall material)
steel (overall material)
overall: 23.6 cm x 35.8 cm x 34.5 cm; 9 9/32 in x 14 3/32 in x 13 19/32 in
ID Number
catalog number
accession number
Credit Line
Gift of O.L. Polinger
See more items in
Medicine and Science: Mathematics
Science & Mathematics
Adding Machines
Data Source
National Museum of American History


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