MONTE, Guidobaldo, Marchese del (1545-1607). Planisphaeriorum universalium theorica. Pesaro: Girolamo Concordia, 1579.

A fine, crisp copy of a treatise on the planisphere by an important patron of Galileo, from the library of Scottish polymath and traveler George Strachan. Dealing with spherical trigonometry on a two-dimensional surface, this book discusses the planispheres of Gemma Frisius and Juan de Rojas, inventor of the universal astrolabe. The author, Guidobaldo Monte, was a mathematician with a particular interest in military architecture. Galileo's essay on hydrostatic balance caught his attention, and Monte secured him a series of patrons ultimately leading to his appointments to the chair of mathematics at Pisa and later Padua. "Guidobaldo was Galileo’s patron and friend for twenty years and possibly the greatest single influence on the Mechanics of Galileo. In addition to giving Galileo advice on statics, Guidobaldo discussed projectile motion with him, and both scientists reportedly conducted experiments together on the trajectories of cannonballs" (DSB). Cinti 4; Riccardi II, 179.

Folio (253 x 185mm). Woodcut on title and diagrams throughout text (a few leaves with gentle toning). Contemporary vellum with remains of ties (upper edge a bit worn). Provenance: George Strachan, c.1572-after 1643, arabist, classicist, mathematician, and traveler (signature on title dated 1611) – Earls of Hopetoun (armorial bookplate).