The Works of Edmund Gunter: Containing the Description and Use of the Sector, Cross-staff, Bow, Quadrant and other Instruments ....

London: A.C. & Francis Eglesfield, 1673. 'Fifth Edition' (actually third edition). 20th cent. three quarter leather by Sangorski.. Very good, bright copy; small spot on the front cover; feint tide mark to a few leaves.. 4to, [24], 309, [3], 224, [168], [4] pp. (with the half title and both engraved & printed title); 3 plates and numerous text illustrations.

An important edition because it was edited by William Leybourn. Leybourn is best known for his books on the use and construction of dials. He was, perhaps, best able to to edit the works (truncated) of the man who devised and constructed one of the most useful mathematical instruments for calculations prior to the slide rule. It is an infrequent occurrence when the editor of a book is as able as the author in his chosen field. Though it is stated 'fifth edition' on the title it is actually the third edition - there being no edition prior to the third of 1653 known. The book is in four parts or sections each dealing with different aspects of instruments and their construction, navigation, and the final section devoted to logarithms. There is a superb folding plate of Gunter's sector bound into the book. This appears to have been intended as a pattern for the manufacture of the sector. Waters has a lengthy account of the sector commenting that Gunter, " ... first made arithmetical navigation a practical proposition at sea ... [this] did but pave the way towards the realization of his main objective, the general adoption of charts on Mercator's projection and the application of the principles of plane trigonometry to the problems of position finding at sea." A handsome copy, complete with half title, engraved title, and leaf of advertisements. Wing G 2241; Crone # 274; see Waters, The Art of Navigation .... (Inventory #: 5133)