Definitions for rabdology
This page provides all possible meanings and translations of the word rabdology
The practice of performing arithmetic using Napier's bones.
the method or art of performing arithmetical operations by means of Napier's bones. See Napier's bones
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 death, it describes three devices to aid arithmetic calculations. The devices themselves don't use logarithms, rather they are tools to reduce multiplication 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 to describe this technique. The rods were used to multiply, divide and even find the square roots and cube roots of numbers. The second device was a promptuary and consisted of a large set of strips that could multiply multidigit numbers more easily than the bones. In combination with a table of reciprocals, it could also divide numbers. The third device used a checkerboard like grid and counters moving on the board to perform binary arithmetic. Napier termed this technique location arithmetic from the way in which the locations of the counters on the board represented and computed numbers. Once a number is converted into a binary form, simple movements of counters on the grid could multiply, divide and even find square roots of numbers.
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