The Odhner Arithmometer

The Odhner Arithmometer and its clones were in production from 1890 (the original arithmometer) through 1970's. The production of its Soviet clone, the Feliks, affectionately known in USSR as Железный Феликс (The Iron Felix, after the nickname of F.E.Dzerzhinsky, the founder of the Soviet Cheka, later known as KGB, now FSB), peaked in 1969 with 300,000 machines built during that year.

The simulator below allows you to experiment with the arithmometer (requires Adobe Flash Player, may not work on mobile platforms). Limitations: the 9th digit does not seem to work and there is no overflow bell. Unfortunately we could not find the author of this simulator.

The Slide Rule

The slide rule was developed in the 17th century and was in wide use until the second half of the 20th century. Simple slide rules support calculations with the precision of 2-3 significant digits, while some exotic models (typically helical scales on the side of a cylinder) support calculations with up to 5 significant digits.

The simulator of a basic slide rule (Pickett 160-ES Microline) shown below was created by Derek Ross (code and images, used with permission) using a freeware drag-and-drop javascript library by Walter Zorn. This simulator may not work on mobile platforms.

slide rule top slide rule slider slide rule bottom slide rule left slide rule right slide rule cursor