The Theory of Perspective.

1766. COWLEY, John Lodge. The Theory of Perspective Demonstrated; in a Method Entirely New. By which the Several Planes, Lines, and Points, used in this Art, are shewn by Moveable Schemes, in the True Positions in which they are to be Considered. [6], xi, [1], 117, [1] pp., with 11 full-page geometric engravings printed on heavy paper, of which 10 are cut-out to demonstrate solid forms. In two volumes. 4to, 268 x 210 mm., bound in contemporary blue glazed paper boards, edges uncut, in half calf folding case. London: Printed for T. Payne, 1766. First edition, second issue, of this rare scientific cut-out book. Cowley's Theory was designed as a geometrical primer with engraved diagrams that could be removed from the book to form solids, thus demonstrating the doctrines of the 11th, 12th, and 15th books of Euclid. The present work amends his Appendix to the Elements to Euclid (1758), and forms a new and more comprehensive attempt to explain the doctrines of planes as applicable to perspective; it is among the most elaborate and most unusual of all eighteenth-century works on geometry and perspective. Included are the eleven engraved plates, of which ten are cut-out to form regular and irregular solids, prisms, pyramids, cones, etc., each accompanied by Cowley's analytic text. Plate IX incorporates strands of coloured cotton thread to illustrate the various projected lines from a single vanishing point. Cowley's mathematical textbooks were extremely popular in their day, widely disseminated and well used, and are rarely found intact. As early as 1806 this work was recorded as "scarce" by Adam Clarke in The Bibliographical Miscellany (cf. Sotheran). Two issues of this first edition were published, one by Bennett in 1765, and the present one by T. Payne. Some spotting throughout, as is true in most copies. Overall, in superb, original condition. ESTC T178295. Vagnetti EIVb47. Lowndes II, 540. Not in Norman, Sotheran Bibliotheca Chemico-Mathematica, Honeyman Collection, Wheeler Gift, or Cajori.