Miscellanea. Hoc est I. Dissertatio de Barometris, & Thermometris, II. Machinae Aritmeticae, eiusque usus Descriptio, III. De Sectionibus Conicis Parallelorum in Horologiis Solaribus Tractatus.

Finely engraved vignette on title & 9 folding engraved plates. 4 p.l., 56 pp. 4to, cont. vellum over boards (a few minor defects to binding). Venice: A. Pavinus, 1709.

First edition of Poleni's first book; it is today a scarce work on the market. It includes dissertations on barometers, thermometers, and conical sections in sundials, as well as an illustrated treatise describing his arithmetical calculating machine.

Poleni invented his "pin-wheel" calculating machine after reading about those of Pascal (1645) and Leibniz (1671). He built it out of wood, but destroyed it when he heard that Brauer, a Viennese machine-maker, had presented another calculating machine to the Emperor. This book is therefore the only record of his invention and its illustrations were the basis of IBM (Italia)'s reconstruction of it.

"The 'pin-wheel' was embodied in a calculating machine which was devised, and constructed in hard wood, by the Italian nobleman, G. Poleni (see his Miscellanea, Venice, 1709). The pin-wheel is a toothed wheel, the number of whose teeth can be varied at will; a simple movement causes 1,2,3...and up to 9 teeth to project; these interact with an equal number of teeth on the cog-wheel controlling the dial whenever the pin-wheel is turned through a complete revolution, and the pointer is moved forward by an equal number of places. Poleni's mechanism for carrying numbers was somewhat akin to Pascal's sautoir, but it was operated by suspended weights instead of by springs."­Wolf, II, p. 656.

Pin-wheels have the advantage over stepped reckoners of occupying less space. They were employed in the nineteenth century by Thomas, and by the Russian inventor W.T. Odhner, whose calculating machine was later developed into the well-known Brunsviga Calculator.

Two of the folding plates depict the whole machine in its supporting frame and the complicated gearing mechanisms at its center.

Fine and fresh copy. Early ink stamp "SIP" on title in two places. Preserved in a box.

❧ Riccardi, I, 290.

Price: $12,500.00

Item ID: 448

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