The Calculator


This stylus-operated non-printing seven-wheeled adding machine is made of steel painted black. Below each wheel is a disc with the digits from 0 to 9 printed close to the center. Each wheel has ten holes, one of which has been cut large enough to reveal a digit on the disc below. Numbers are entered by rotating wheels. Clockwise rotation adds a digit, counterclockwise subtracts. The result appears in the large holes of the wheels. The two rightmost and the two leftmost wheels are painted black. The three center ones are unpainted. This makes it easy to distinguish cents, dollars up to $999, and larger amounts. The machine is marked: THE CALCULATOR CO. (/) GRAND RAPIDS, MICH. (/) PATD. The back of the instrument is covered with green felt. The silver-colored metal stylus resembles a nut pick. Documentation is stored separately.

This example was donated to the Smithsonian by Richard J. De Prez, who inherited it from his father.

Compare to Smallwood calculator (see MA.336184).


Popular Science Monthly, July, 1920, vol. 97, p. 9 - advertising for agents - machine sold for $12.50. According to Robert Otnes, the Calculator Corporation was at the address in Grand Rapids given on 1982.0542.02 (trade literature relating to this object) in the 1917 Grand Rapids city directory. Before this it had a different name and afterward a different address. By 1920 it moved to a different building.

Date Made: 1920

Maker: Calculator Corporation

Location: Currently not on view

Place Made: United States: Michigan, Grand Rapids

Subject: Mathematics


See more items in: Medicine and Science: Mathematics, Adding Machines, Science & Mathematics


Exhibition Location:

Credit Line: Gift of Richard J. DePrez

Data Source: National Museum of American History

Id Number: 1986.0542.01Accession Number: 1986.0542Catalog Number: 1986.0542.01

Object Name: adding machine

Physical Description: brass (overall material)steel (overall material)Measurements: overall: .5 cm x 26.7 cm x 6.3 cm; 3/16 in x 10 1/2 in x 2 15/32 in


Record Id: nmah_690295

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