1614
John Napier invents logarithms

Scottish mathematician John Napier published his 1614 work, "Mirifici Logarithmorum Canonis Descriptio" (A Description of the Wonderful Law of Logarithms) which described the mathematical technique of logarithms, together with 90 pages of logarithm tables.

Logarithms are a mathematical tool that reduces division to a process of subtraction, and multiplication to a process of addition. They were extremely important for simplifying calculations found in diverse fields such as astronomy, navigation, and engineering.

The term logarithm comes from the Greek words for ratio (logos) and number (arithmos).

Complex multiplication problems become much simpler addition problems with logarithm tables. To calculate the product of two numbers, you look up each number in the table to find its logarithm, add those logarithms together, then look up the result in the table to find the number with that logarithm. Similarly, division problems become subtraction problems with logarithms.

Related information:

• Maths is Fun: Introduction to Logarithms
• John Napier: National Library of Scotland's Scottish Science Hall of Fame

Image:

• John Napier of Merchiston by Richard Cooper. Line engraving, mid 18th century. NPG D28039
  Credit: © National Portrait Gallery, London, Creative Commons BY-NC-ND 3.0