Occhio errante dalla ragione emendato. Prospettiva

Venice: Lucio Spineda, 1628. SOLE EDITION. Hardcover. Fine. Contemporary limp vellum in fine condition (paste-down torn). The text is in excellent condition with a few instances of light toning (in gatherings O, S, and X), and a small worm-track in the margin of the first few lvs. The text is illustrated with woodcut diagrams. An extremely rare book. OCLC cites only 1 copy in North America (Columbia University) and 5 other institutional copies outside of Italy (two in Denmark, two in France, one in Switzerland). Vagnetti described the book without having seen a copy. Riccardi described an incomplete copy. First (and only) edition of this wide-ranging work on selected problems in perspective and its underlying geometry, largely organized around what the author considers to be commonly found theoretical or practical errors. Diano proves himself to be well read in the contemporary literature of optics and perspective, citing Kepler, Maurolico, Aguilon, and others. The final two chapters describe perspective instruments of the variety used by Dürer.

Ferdinando di Diano (born around 1571) was an Italian mathematician, philosopher, and theologian, author of some fifteen texts on various subjects, including the natural sciences.

In "The Eye, Wandering from Reason, Emended. Perspective"(1628), Diano distinguishes between 'perspectiva naturalis' (physiological optics) and 'perspectiva artificialis' (the graphic method that allows the rationalization of space). Diano considers human perception via 'perspectiva naturalis' to be fallible; one cannot be sure what one perceives visually is true or merely a 'deception of the mind'. That is, the observer does not know if the images that reach the retina are altered in some way by the mind. By contrast, through 'perspectiva artificalis' (using optical and measuring tools to "construct" an accurate perspective view), the individual can affirm the reliability of one's senses.

It is this enhancement of the ability of men to thwart the illusions of visual perception that is at the heart of the "The Eye, Wandering from Reason, Emended. Perspective." In Diano's views, it is the ability to distinguish our perception from reality that distinguishes the soul of rational people from those of madmen and beasts.