The description and use of the Sector, Cross-staff and other instruments

Frontispiece to 'The description and use of the Sector, Cross-staffe and other instruments' by Edmund Gunter (1581-1626), Professor of Astronomy at Gresham College, London from 1619. First published in 1624, this print is from the 2nd edition. Gunter published seven figure tables of logarithms of sines and tangents in 1620 in Canon Triangulorum, or Table of Artificial Sines and Tangents. The words cosine and cotangent are due to him. He made a mechanical device, Gunter's scale, to multiply numbers based on the logs using a single scale and a pair of dividers. It was called the 'gunter' by seamen and was an important step in the development of the slide rule. Gunter published his description in 1624 in 'The Description and Use of the Sector, the Crosse-staffe and other Instruments'.