Author(s):
Frank J. Swetz (Pennsylvania State University)
William Leybourn (1626-1716) was a London surveyor and teacher of mathematics. Leybourn wrote several books on land surveying and the use of measuring instruments. His Description and Use of a Portable Instrument, ... Gunter’s Quadrant was revised by the astronomer Charles Leadbetter (fl. 1728) and was published as a third edition in 1731.
Source: Oughtred Society, Archive of Collections, Tom Wyman Collection. Tom Wyman (1927-2014) was the first president of the Oughtred Society. Wyman amassed an extensive collection of early slide rules and books related to them. The image above is #55 in the Wyman Collection.
Index to Mathematical Treasures
Frank J. Swetz (Pennsylvania State University), "Mathematical Treasure: Manual for Use of Gunter's Quadrant," Convergence (June 2018)