John Napier, Scottish mathematician, c 1600.
© Science Museum / Science & Society Picture Library
John Napier (1550-1617), a member of the landed gentry, was born at Merchiston Castle in Edinburgh, Scotland. He studied at St Andrews University and travelled widely throughout Europe before returning to Scotland, where he pursued his interest in mathematics as a hobby. He spent 20 years on the research that would lead to his discovery of logarithms (mathematical functions used to simplify complex multiplication and division) in 1614. He is also thought to have introduced the decimal point into common usage. However, he is probably best known for his invention of a calculating machine which used a set of ivory rods and became known as 'Napier's Bones' or 'Napier's Rods'.