1-158-190 - Oxford Science Archive/Heritage Images

Method of measuring angles with a cross-staff, 1636. Edmund Gunter (1581-1626) was an English mathematician and astronomer who invented many measuring instruments which bear his name; Gunter's Chain, the 22-yard-long, 100-link chain used by surveyors; Gunter's Line, the forerunner of the modern slide-rule; Gunter's Scale, a navigational tool; and the portable Gunter's Quadrant. He also introduced the words cosine and cotangent into the language of trigonometry. From The Description and Use of the Sector by Edmund Gunter. (London, 1636).