John Napier

John Napier 1550-1617, Scottish mathematician. He invented logarithms and wrote Mirifici logarithmorum canonis descriptio (1614), containing the first logarithmic table and the first use of the word logarithm. His Rabdologiae (1617) gives various methods for abbreviating arithmetical calculations. One method of multiplication uses a system of numbered rods called Napier's rods, or Napier's bones; this was a major improvement on the ancient system of counters then in use. In 1619, after Napier's death, his Mirifici logarithmorum canonis constructio, which gave the method of construction of his logarithms, was published by his son Robert and edited by Henry Briggs. Napier introduced the decimal point in writing numbers. Napier was also known as an outspoken exponent of the Protestant cause. His religious writings include A Plaine Discovery of the Whole Revelation (1593), the earliest Scottish interpretation of the scriptures.

Napier, John (1550–1617). Mathematician. Napier invented logarithms, greatly simplifying calculations involving multiplying and dividing. As Kepler put it, he doubled the life of astronomers (by halving the time they took number-crunching). He was 8th laird of Merchiston. Educated in France and then at St Andrews, he published his Mirifici logarithmorum canonis descriptio in 1614, with tables and explanations. The basic principle was to reduce multiplication to addition by using powers: thus 10²×10³=10⁵. In the course of 20 years' work, he came up with the base 10 for logarithms, so that the examples above would be 2, 3, and 5. In 1617, he published Rabdologia, describing ‘Napier's bones’, or rods calibrated logarithmically; as developed into the slide rule, this was essential in science and engineering until the electronic calculator was invented.

David Knight

Napier, John (1550–1617). Mathematician. Napier invented logarithms, greatly simplifying calculations involving multiplying and dividing. As Kepler put it, he doubled the life of astronomers (by halving the time they took number‐crunching). Educated in France and then at St Andrews, he published his Mirifici logarithmorum canonis descriptio in 1614, with tables and explanations. In 1617, he published Rabdologia, describing ‘Napier's bones’, or rods calibrated logarithmically; as developed into the slide rule.