SNEL, Willebrord (1580-1626). Tiphys batavus, sive histiodromice, de navium cursibus, et re navali. Leiden: Elzevier, 1624.

Details
SNEL, Willebrord (1580-1626). Tiphys batavus, sive histiodromice, de navium cursibus, et re navali. Leiden: Elzevier, 1624.

4o (194 x 150 mm). 3 full-page engravings (the chart slightly shaved), diagrams in text. (Title-page slightly soiled.) Contemporary calf (rebacked preserving original backstrip, dried and rubbed); cloth folding case.

FIRST EDITION. Named after the pilot of the mythical ship Argo, Snel's navigational treatise was mainly a study and tabulation of Pedro Nuez's "rhumb lines," which Snel named "loxodromes." Pedro Nuez Salaciense (1502-1578) made a significant discovery based on on observations reported to him in 1533 by Admiral Martim Afonso de Sousa. They related to rhumb line sailing and to great circle sailing. He demonstrated for the first time the spiral nature of these lines, which denote the quarters of the wind on navigational charts. Snel's "consideration of a small spherical triangle bounded by a loxodrome, a parallel, and a meridian circle as a plane right triangle foreshadows the differential triangle of Pascal and later mathematicians" (DSB). Willems 224; Norman 1964.