Comptometer, Macaroni Box Model

This is the prototype for the Comptometer, a key-driven adding machine invented by Dorr E. Felt of Chicago. It is a scarred wooden box (originally used to transport macaroni) that contains the levers and wheels for a 5-column adding machine with one partial column of keys (wooden skewers), four of which are missing. The number dials are at the front. Two screws are on the top of the back panel. A series of rubber bands, used to set the levers to accept the next keystroke, are missing.
Compare to replica, which has catalog number MA*323646.
J. A. V. Turck, Origin of Modern Calculating Machines, Chicago: Western Society of Engineers, 1921, pp. 52-56.
Object Name
adding machine
date made
Felt, Dorr E.
Physical Description
wood (overall material)
cork (overall material)
metal (overall material)
overall: 25 cm x 20 cm x 52.5 cm; 9 27/32 in x 7 7/8 in x 20 21/32 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
Inventing In America
Data Source
National Museum of American History, Kenneth E. Behring Center
Credit Line
Gift of the Heirs of Dorr E. Felt
Additional Media

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