Gunter, Edmund,1581–1626, English mathematician and astronomer, educated at Westminster School, London, and Christ Church, Oxford. He invented (1618) a small portable quadrant and discovered (1622) the variation of the magnetic compass. His Gunter's chain is a surveyor's chain graduated on the decimal scale. He devised Gunter's scale, a logarithmic scale of equal parts as well as trigonometric functions, which with the aid of compasses served as a slide ruleslide rule,
instrument for making numerical computations and readings, the results of which may be read easily and quickly after performing simple mechanical manipulations.
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