Odhner Arithmometer
Odhner Arithmometer

The first mechanical adding machine was made by the French mathematician Blaise Pascal in 1645. This had a number of interconnected wheels, each with ten teeth representing the digits. Numbers were added by advancing the appropriate wheels. The German philosopher Gottfried Wilhelm von Leibniz extended to Pascal’s machine to doing multiplication by repeated addition.

The mechanical principles of these adding machines were used in hand cranked calculators during the 18th and 19th centuries and electrically powered calculators up to the 1950s.

The first calculating machine to be produced in large numbers was made in France by Thomas de Colmar in 1820. The machine, called an “Aritherometer” and its clones was made up until the 1920s

Facit calculator (1954)
Facit calculator (1954)

In 1905, the Swedish inventor Willgodt Odhner made an adding machine based on a pinwheel mechanism. Dozens of companies made machines incorporating this mechanism which soon superseded the Colmar design. The market leaders were Swedish company Facit, founded in 1918, and the American company Monroe, founded in 1911. Both closed in 1960.

 

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