Rabdology
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In 1617 a treatise in Latin titled Rabdologiæ and written by John Napier was published in Edinburgh. Printed three years after his treatise on the discovery of logarithms and in the same year as his d
Cover page of Rabdologiæ
Napier's bones
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Napier's bones is a manually operated calculating device created by John Napier of Merchiston, Scotland for the calculation of products and quotients of numbers. The method was based on lattice multip
Rabdology
…and division of natural numbers to simple addition and subtraction operations. The first device, which by then was already popularly used and known as Napier's bones, was a set of rods inscribed with the multiplication table. Napier coined the word rabdology (from Greek ῥάβδος [rhabdos], rod and λόγoς [logos…
A set of Napier's bones
An unusual 18th-century set of Napier's bones in which the numbers are on rotating cylinders rather than rods of square cross-section