Slide rule

The slide rule, also known colloquially in the United States as a slipstick, is a mechanical analog computer. The slide rule is used primarily for multiplication and division, and also for functions such as roots, logarithms and trigonometry, but is not normally used for addition or subtraction. Though similar in name and appearance to a standard ruler, the slide rule is not ordinarily used for measuring length or drawing straight lines.

Slide rules exist in a diverse range of styles and generally appear in a linear or circular form with a standardized set of markings (scales) essential to performing mathematical computations. Slide rules manufactured for specialized fields such as aviation or finance typically feature additional scales that aid in calculations common to those fields.

The Reverend William Oughtred and others developed the slide rule in the 17th century based on the emerging work on logarithms by John Napier. Before the advent of the pocket calculator, it was the most commonly used calculation tool in science and engineering. The use of slide rules continued to grow through the 1950s and 1960s even as digital computing devices were being gradually introduced; but around 1974 the handheld electronic scientific calculator made it largely obsolete and most suppliers left the business.

Slide rule (disambiguation)

A slide rule is a mechanical analog computer.

Slide Rule may also refer to:

Slide Rule (horse)

Slide Rule (1940 - ) was a Thoroughbred race horse who was owned by William E. Boeing of Boeing. He sired by Metropolitan and Suburban Handicap winner, Snark and was out of the mare King's Idyll, a daughter of the outstanding Champion sire and broodmare sire, Sir Gallahad III.

He was a stablemate of the more noted Devil's Thumb, and in April 1943, of the colt Twoses. Newspaper reports of the early 1940s described him as a little chestnut colt.

Competition chronicle

Slide Rule's first victory of significance came in the Babylon Handicap at Aqueduct Race Track on September 5, 1942. The colt emerged from the middle of the pack to take the $7,325 purse. He won a Kentucky Derby trial, the Experimental Handicap, at Jamaica, New York, on April 8, 1943. The field of fifteen included thirteen Derby eligibles.

On June 4, 1942 Slide Rule was part of an owner - trainer - jockey double for W.E. Boeing, Cecil Wilhelm, and Ralph Neves at Belmont Park. Larrup, the other Boeing entry, won the first event with Slide Rule completing the double.