Napier's rods, 17th century.

Image number: 10328823

Napier's rods, 17th century.

John Napier (1550-1617), discoverer of logarithms, created the popular calculating tool known as Napier's rods or bones. Napier's rods reduced muliplication to a sequence of simple additions; division and square roots could also be achieved. This instrument consists of a wooden box containing ten rotating cylinders each of which bears the numbers '0 times' to '9 times'. These sets would have been made to order for a wealthy client and regarded more as an adornment and status symbol than as tools for practitioners. Made by Dring and Fage, England.

Image number:
Science Museum/Science & Society Picture Library
Date taken:
30 October 2003 09:22
Image rights:
Science Museum

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