Napier's system

Early in the seventeenth century, Scottish mathematician John Napier (1550-1617), Baron of Merchiston, developed a simplified method of multiplication and division. Napier's system, which he called logarithms (commonly abbreviated to "logs"), allows one to reduce multiplication to addition, and division to subtraction, using exponents of 10. For example, the log of 100 (102) is 2 and the log of 1000 (103) is 3. The multiplication of 100 x 1000, which equals 100,000, can be accomplished by adding the numbers' logs: log(100) + log(1000) = 2 + 3 = 5. The number with a logarithm 5 is 100,000.

Napier published his methodology in A Description of the Admirable Table of Logarithms in 1614. In 1617, he published a description of a device based on the principles of logarithms.