Napiers calculating tables

1614 – Invention of Napier’s Rods – Logarithms

Our excurse into History of Computer continues with 1614 , when John Napier invented a system of moveable rods (Napier’s Rods) based on logarithms. This new system allowed to multiply, divide and calculate square and cube roots

John Napier was born in Edinburgh, Scotland, into the Scottish nobility. Since his father was Sir Archibald Napier of Merchiston Castle, and his mother, Janet Bothwell, was the daughter of a member of Parliament, John Napier became the laird (property owner) of Merchiston. Napier’s father was only 16 when his son, John, was born. As was the practice for members of nobility, Napier did not enter school until he was 13. He did not stay in school very long, however. It is believed that he dropped out (perhaps we was the first most successful school dropout?) and traveled in Europe to continue his studies.

As a person of high energy and curiosity, Napier paid much attention to his landholdings and tried to improve the workings of his estate. He was known as “Marvellous Merchiston” for the many ingenious mechanisms he built to improve his crops and cattle. In addition to these adventures, he described military devices that were similar to today’s submarine, machine gun, and army tank. He never attempted to build any of the military instruments, however.

Napier had a great interest in astronomy, but he was not your average star gazer. His interest in stars led to John’s contribution to mathematics. Napiere was involved in research that required lengthy and time consuming calculations of very large numbers. Once the idea came to him that there might be a better and simpler way to perform large number calculations, Napier focused on the issue and spent twenty years perfecting his idea. The result of this work is what we now call logarithms.

Napier realized that all numbers can be expressed in what is now called exponential form, meaning 8 can be written as 23, 16 as 24 and so on. What make logarithms so useful is the fact that the operations of multiplication and division are reduced to simple addition and subtraction. When very large numbers are expressed as a logarithm, multiplication becomes the addition of exponents.

Napier first made this discovery known in 1614 in his book called A Description of the Wonderful Canon of Logarithms. The author briefly described and explained his inventions, but more importantly, he included his first set of logarithmic tables. These tables were a stroke of genius and a big hit with astronomers and scientists. It is said that English mathematician Henry Briggs was so influenced by the tables that he traveled to Scotland just to meet the inventor . This lead to a cooperative improvement including the development of Base 10.

Napier was also responsible for advancing the  Simon Stevin’s notion of the decimal fraction by introducing the use of the decimal point. His suggestion that a simple point could be used to separate whole number and fractional parts of a number soon became accepted practice throughout Great Britain. Arab lattice multiplication, used by Fibonacci, was made more convenient by his introduction of Napier’s bones, a multiplication tool using a set of numbered rods.

And we all know that today’s world of complex computer networks and programs we’d be nowhere without decimal points nor logarithms… The way was opened to later scientific advances, in astronomy, dynamics, physics; and also in astrology.

So here is to John Napier and his invaluable contribution into computer history!