Curta Type II Calculating Machine

This compact cylindrical handheld calculating machine has gray metal sides and a black top and operating handle. There are 11 slots along the side of the cylinder with 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 eight digits large. The result also is indicated around the edge of the top, and may be up to 15 digits large. The top may be rotated, as one one would move a carriage on an earlier stepped drum machine. Sliding markers indicate decimal divisions 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. Operating instructions were received with the machine and are stored with it. The machine fits in a black metal cylindrical case. The lid of the case turns clockwise to open.

The machine and case are marked: CURTA, A mark on the bottom of the object reads: Type II (/) No 517304 (/) Made in Liechtenstein (/) (Customs Union with Switzerland) (/) by Contina Ltd Mauren (/) System Curt Herstark. The machine is marked on the lid: OPEN.

The Curta calculating machine was invented the Austrian Curt Hertzstark (1902–1988). He worked on the design during World War II as a prisoner at the Nazi concentration camp of Buchenwald, and produced the machine after the war in Liechtenstein. The Curta Type II was sold from at least 1954 until early 1972, when handheld electronic calculators replaced it.

For related documentation, see 1983.0471.06 and 1983.0471.07

References:

Curt Hertstark, Interview with Erwin Tomash, September 10 and 11, 1987, Oral History 140, Charles Babbage Institute, Minneapolis, Minnesota. 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.

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