42 - BUTEO (Jean). *Opera geometrica*. Lyon, Thomas Bertellus, 1554. In-4 (232 x 167 mm), contemporary binding in fawn calfskin, with extensive decoration on the covers consisting of interlacing patterns and arabesques punctuated by fleurons, all enhanced with brown, green, and red wax, spine with raised bands adorned with gilded fleurons, marbled edges.

BUTEO (Jean). *Opera geometrica*. Lyon, Thomas Bertellus, 1554. In-4 (232 x 167 mm), contemporary binding in fawn calfskin, with extensive decoration on the covers consisting of interlacing patterns and arabesques punctuated by fleurons, all enhanced with brown, green, and red wax, spine with raised bands adorned with gilded fleurons, marbled edges. A rare first edition of the works of the scholar and geometer Jean Buteo, whose real name was Jean Borrel (1492–1572). A native of the Dauphiné region and a canons regular of the Order of Saint Anthony, Buteo was sent to Paris to study under Oronce Fine and invented various mathematical instruments. He notably distinguished himself by refuting those who believed they had found the solution to the quadrature of the circle. This work, illustrated with initial letters and numerous woodcut figures, brings together fifteen articles on various scientific topics, the first nine of which are devoted to geometric or mechanical problems; among these, Ad problema cubi duplicandi stands out as the most original; in it, the author exposes Michael Stifel’s errors regarding the duplication of the cube and provides his own approximation of the cube root of two; the last six articles deal with mathematical aspects related to issues such as the division of land, inheritances, or divorce and are among the earliest studies on these subjects. An exceptional copy bound in a very elegant binding with a decoration that is both rich and airy, blending, in perfect balance, interlacing patterns and arabesques finished with azure fleurons or enhanced with colored wax. Spine restored. Acquired by Émile Rossignol in 1958.