1-158-177 - Oxford Science Archive/Heritage Images

Title page of The Description and Use of the Sector by Edmund Gunter, 1636. It shows mariners holding various navigational instruments, including a sector and a cross-staff at the top, and a horary quadrant at bottom right. 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. (London, 1636)