Find out who invented the slide rule.
The slide rule was invented by several people. The slide rule is based on the use of logarithmic scales, which were invented by John Napier (1550-1617), Baron of Merchiston, and published in 1614. In 1620, Edmund Gunter (1581-1626) of Gresham College, London, England, described an immediate forerunner of the slide rule, his logarithmic line of numbers. William Oughtred (1574-1660), Rector of Aldbury, England, made the first rectilinear slide rule in 1621. This slide rule consisted of two logarithmic scales that could be manipulated together for calculation.
His former pupil, Richard Delamain published a description of a circular slide rule in 1630, three years before Oughtred published a description of his invention (at least one source says that Dela-main published in 1620). Oughtred accused Delamain of stealing his idea, but evidence indicates the inventions were probably arrived at independently.
The earliest existing straight slide rule using the modern design of a slider moving in a fixed stock dates form 1654. A wide variety of specialized slide rules were developed by the end of the 17th century, for trades such as masonry, carpentry and excise tax collecting. Peter Mark Roget (1779-1869), best known for his Thesaurus of English Words and Phrases, invented a log-log slide rule for calculating the roots and powers of numbers in 1814. While the slide rule was popular as a calculating tool for several centuries, it has largely been superseded by the electronic calculator.