Wooden Box Model Comptometer

This key-driven non-printing adding machine has eight columns of metal keys with nine keys in each column. It is an early production model of an adding machine designed by Dorr E. Felt of Chicago.
The keys in each column are stamped with the digits from 1 to 9 and the digits are painted white. No complementary digits are indicated, and the key tops are flat and entirely of metal. There is a spring around each key stem and the key stem passes through the key top. The stems become progressively longer as the digits become larger. The case is of cherry. The lower part of the metal plate on the front side is missing. Nine windows in the upper part of this plate reveal digits on nine number wheels that indicate totals. A zeroing lever and knob are on the right side of the machine. There are no decimal markers or subtraction levers.
A metal tag screwed to the top of the machine behind the keyboard reads: FELT & FOSTER (/) CHICAGO (/) PAT’D JULY 19.87.OCT 11.87. A label received with the machine indicates that it was used by Mr. G. W. Martin in offices of the Chicago Gas Company from 1887 to 1903.
A metal model tag stored with the object reads: 3. Photographs in the Accession Journal of Felt & Tarrant Manufacturing Company indicate that machine #3 in that collection was rather different, resembling more closely a wooden box Comptometer in the Smithsonian collections with catalog number MA*273035.
References: U.S. Patents 366945 and 371496.
Felt & Tarrant, Accession Journal, 1991.3107.06.
J. A. V. Turck, Origin of Modern Calculating Machines, Chicago: Western Society of Engineers, 1921.
Currently not on view
Object Name
adding machine
date made
Felt & Foster
Physical Description
cherry wood (overall material)
metal (overall material)
overall: 12.9 cm x 19.2 cm x 36 cm; 5 3/32 in x 7 9/16 in x 14 3/16 in
place made
United States: Illinois, Chicago
ID Number
catalog number
accession number
Science & Mathematics
Adding Machines
See more items in
Medicine and Science: Mathematics
Adding Machines
Data Source
National Museum of American History, Kenneth E. Behring Center
Credit Line
Gift of Victor Comptometer Corporation
Additional Media

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