Napier's Chessboard Calculator

In an appendix contained in Napier's book entitled "Rabdologia", he described a means of computation through the means of a chessboard, though using chips similar to checkers rather than chesspieces. While Napier used the characters a and b to represent the digits of the numbers on the board, it is clear now that substitution of 0 and 1 for these characters reveals the now common binary positional notation. [NOTE: the phrase "binary notation" implies the use of two characters in the representation system, not necessarily 0 and 1.]

Using the chessboard, Napier described the methods of computing all four standard arithmetic operations (add, subtract, multiply and divide) as well as the extraction of square roots. In this emulation we provide demonstrations of three operations:

Last updated 2001/08/09
© J.A.N. Lee, 2001.