Ridley, Mark

4to (6 3/4 x 5 1/8 in.; 170 x 126 mm). Engraved title by Renold Elstrack, engraved portrait, 21 engravings in text (one with two maps showing New England, Virginia and Terra Australis), printer's woodcut device on last leaf X3, lacking the volvelle and final blanks, cropped occasionally affecting headlines and text at foot; with errata and Tixover advertisement on X3r. Modern red morocco gilt, by Elizabeth Greenhill; quarter morocco folding case.

Robert Dunham (pencil inscription on front pastedown; Sotheby's New York, 11 December 1993, lot 764) — Edward Tufte (bookplate, Christie's New York, 2 December 2010, lot 18) 

STC 21045; Sabin 71297; Taylor, The Mathematical Practitioners of Tudor & Stuart England, p. 126

First edition, second issue. Ridley, following William Gilbert's work De magnete, "here presented directions for a series of experiments on the lodestone, magnet, and terella which could be carried out by anyone interested in the subject. He added engravings and descriptions of his improvised instruments for determining the variation, and for making use of the inclinatory needle for finding position at sea. This was in accordance with the method published jointly by Edward Wright, Thomas Blundeville and Henry Briggs."