Curta Type II Calculating Machine

This compact cylindrical handheld stepped drum calculating machine has gray metal sides and a black top and operating handle. Eleven slots along the side of the cylinder have plastic red and black levers that are pulled down to set numbers. The digit entered appears at the top of the slot. Multipliers are indicated by numbers read through holes around the edge of the top and may be up to 8 digits large. The result also is indicated around the edge of the top, and may be 15 digits large. The top rotates, as one one would move a carriage on an earlier stepped drum machine. Sliding markers indicate the position of decimals for entries, multipliers, and results.
To zero the machine, the carriage is raised and the black disc under the operating lever is rotated through one turn using a clearing lever with a ring-like handle. The operating handle is pulled up for subtraction and division. Moving a lever on the side of the cylinder causes subtraction rather than addition in the revolution counting register. The machine fits in a black metal cylindrical case.
The machine is marked on the side: CURTA. The bottom reads: Type II (/) No 515677 (/) Made in Liechtenstein (/) (Customs Union with Switzerland) (/) by Contina Ltd Mauren (/) System Curt Hertstark. The side of the case reads: CURTA (/) OPEN. It also reads: PROPERTY OF HERBERT L. WATKINS.
Compare to 1983.0471.05.
Curt Hertstark, Interview with Erwin Tomash, September 10 and 11, 1987, Oral History 140, Charles Babbage Institute, Minneapolis, Minn. Hertstark dates the beginning of production of the Curta to 1949.
Cliff Stoll, “The Curious History of the First Pocket Calculator,” Scientific American, (January 2004), pp. 82-89. The Model II reportedly was introduced in 1954, after Hertstark had left the company.
Currently not on view
Object Name
calculating machine
date made
Contina Ltd Mauren
Physical Description
plastic (overall material)
metal (overall material)
overall: 14 cm x 6.9 cm x 6.9 cm; 5 1/2 in x 2 23/32 in x 2 23/32 in
place made
ID Number
catalog number
nonaccession number
maker number
Science & Mathematics
Calculating Machines
See more items in
Medicine and Science: Mathematics
Calculating Machines
Data Source
National Museum of American History, Kenneth E. Behring Center
Credit Line
Gift of LaVerne Watkins
Additional Media

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