CAMPANI, Giuseppe.

Discorso di Giuseppe Campani, intorno a' suoi muti oriuoli, alle nuove sfere Archimedee & ad un' altra rarissima, & utilissima inventione de personaggio cospicuo.

      Roma, Francesco Moneta, 1660. In-12, [dimension: 108 x 78 mm] de (16), 111 pp., 1 f. bl. Vélin. (Reliure de l'époque.) Première édition de cet ouvrage "d'une rareté légendaire" selon Weil. Les frères Matteo et Giuseppe Campani, maîtres horlogers romains, ont inventé une horloge à balancier, au même moment qu'Huygens, dont ils ne connaissaient pas les travaux. Le pape Alexandre VII leur avait commandé une horloge "muette", qui n'émette pas le tic-tac ordinaire et dont l'heure soit lisible même de nuit. "This little book is of particular interest, not on the account of the silent clocks, but because it describes the accidental invention by the author of a pendulum as applied to a clock, and adduces some evidence on the question of Huygens' priority in the application of the pendulum. (...) In trying different arrangements of balance, Giuseppe lenghtened the arms of the balance and attached by wax two leaden weignts at their ends. While he was watching the action, the upper weight fell off, leaving only the lower weight and, to his astonishment, the clock containued to work, with the balance out of equilibrium; further he found the going extremely regular. He then showed the clock to his brother, who remarked that it was a great invention, discovered accidentally, applicable to all kinds of clocks, and that it was in fact the pendulum discovered by Galileo Galilei for measuring accurately the time in his celestial observations. (...) I feel not doubt that Giuseppe did discover the application of a pendulum to a clock, without knowledge of Huygens' recent work." (Baillie). La "sphère d'Archimède" présentée à la fin du volume est l'instrument à mouvement perpétuel de Cornelius Drebbel offert à James 1er. Le seul exemplaire à notre connaissance, mis en vente au XXe siècle est celui du Dr. Weill vers 1960, qui est décrit "Contemp. limp vellum" et qui est probablement cet exemplaire. Bel exemplaire. Riccardi 1, 218 (ne cite que l'exemplaire de la Marciana). Weil, Catalogue 29 n°23 : "of legendary rarity" (probably this copy). Baillie, Clocks and watches, An historical bibliography pp. 59-60. More details and pictures on request