Gunter, Edmund (1581-1626)

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 rule.