John Napier (1550 - 1617) was a Scottish mathematician, who made many contributions to arithmetic, including the invention of logarithms. When Kepler found out about Napier's logarithms he applied them to Tycho Brahe's stellar and planetary observations, and established his famous three laws of planetary motion.
John Napier is also remembered for 'Napier's Bones', a calculating device that allowed the user to carry out multiplication and division. When Napier was alive, most people could add and subtract small numbers, but very few people could multipy, and long division was considered a university subject!
Using the 'bones' you can carry out multiplication and division. For example if you want to multiply 12345 x 6, you arrange the bones in the correct order, and simply read off the answer. However should you wish to multiply a number that contains a digit that occurs more than once, eg 266255, then you will need some extra bones. You can either buy a second set, or you can photocopy the existing set of bones.
We include a specially written booklet, that explains how to get the best from your 'bones'. Napier