GALILEI, Galileo


GALILEI, Galileo La operazione del compasso geometrico.

Padua, per Paolo Frambotto, 1640


4to. pp. (viii) 80, 2 fold-out plates. Roman letter, little Italic. Woodcut printer’s device to t-p, fold-out plate with engraved astronomical diagrams, line and woodcut illustrations, decorated initials and headpieces. Faint ink spots to t-p, slight foxing in places, couple of gatherings browned, two holes at gutter of last touching a letter. A very good copy in carta rustica, later eps. Bookplate of Erwin Tomash to front pastedown, armorial bookplate of Ricasoli Firidolei to verso of t-p. In modern folding box.

Very good copy of the second edition—the first with the plate—of this major work in the history of computing. The world-renowned symbol of Renaissance scientific progress, the Italian astronomer and physician Galileo Galilei (1564-1642) was professor at Pisa and Padua, and the inventor of scientific instruments like the thermoscope (an early thermometer) and, most famously, a more powerful telescope with which he first identified, among other major discoveries, Jupiter’s four moons. His support of heliocentric theories and Copernicanism caused him accusations of heresy against which he was summoned to defend himself in front of the Inquisition. The ‘compasso geometrico’ was another of his creations, first discussed in print in 1606. Made of two rulers joined by a volvelle—as shown in the engraved plates—the compass could be used to calculate distance, height, depth and a variety of proportional operations through a system of scales based on Euclid’s study of triangles. In the dedicatory letter, the printer Frambotto celebrated Galileo’s ‘maraviglioso compasso’ as having ‘fundamental importance for the art of war’ and being ‘sought after by leading Captains’; it also addressed everyday problems in civil life. After explaining how the ruler on the compass is subdivided into sections, he proceeds to explore different applications. These include theoretical operations like cube roots, the squaring of a circle and geometrical proportions, as well as practical ones like the scale increase or reduction of the plan of a geographical area, the translation of prices from one currency to another according to their relative value, the calculation of interests and the arithmetic subdivision of armies on the battlefield. In his letter to the reader, Galileo stated that his ‘compasso’ would allow ‘anyone to solve in an instant the most difficult arithmetical operations’ without being skilled mathematicians.

Tomash & Williams G12; Brunet II, 1462: ‘très rare’; Honeyman IV, 1395; Riccardi I/1, 506: ‘buona edizione’. Not in BM STC It. C17 or Smith, Rara.

In stock