Comptometer - Wooden Box Model

This key-driven non-printing adding machine has a metal mechanism, steel keys with German silver and plastic key tops, and steel dials at the front that record the result. It is a production model of the Comptometer made by Felt & Tarrant Company of Chicago during its early years.
The eight columns of keys have nine keys each. Celluloid discs in the key tops are color-coded to mark off dollars and cents. Complementary digits are indicated on the discs, to aid in subtraction. The key tops are alternately concave (odd digits) and flat (even digits). There is a spring around each key stem. Eight levers above the dials serve as decimal markers. Nine windows at the front of the machine reveal the result.
A metal piece to the left of each “1” key is moved to prevent carrying when the complementary digits are used for subtraction. Depressing a lever on the right side of the machine allows one to turn a nearby knob and zero the number dials.
The serial number, indicated in the front center of the machine under the decimal markers, is 1876. A second mark, on a metal tag screwed to the machine in back of the keyboard, reads: TRADE COMPTOMETER MARK (/) PAT’D (/) JUL.19.87 JUN. 11. 89. (/) OCT.11.87 NOV.25.90 (/) JAN.8.89 DEC.15.91. (/) Felt & Tarrant Mfg. Co. (/) CHICAGO.
This machine was transferred to the Smithsonian from the U.S. Geological Survey in 1908.
1991.3107.06 (Catalog of the Felt & Tarrant collection).
Currently not on view
Object Name
adding machine
date made
Felt & Tarrant Manufacturing Company
Physical Description
cherry wood (overall material)
metal (overall material)
plastic (overall material)
overall: 15.7 cm x 21 cm x 38.4 cm; 6 3/16 in x 8 9/32 in x 15 1/8 in
place made
United States: Illinois, Chicago
ID Number
maker 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
Transfer from US Geological Survaey
Additional Media

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