BALIANI, Giovanni Battista De motu naturali gravium solidorum et liquidorum. Genoa, Giovanni Maria Farroni, 1646
4to (193 x 236 mm), pp 174 [6, including terminal blank leaf], with printer's device on title and numerous woodcut diagrams in text; a fine, unpressed copy in later vellum, the Franklin Institute copy with bookplate and stamp on verso of title. £7500
Second edition (first 1638) but essentially a new work. 'In the second edition [Baliani] speculated on the possibility that in unmeasurably small successive finite times, the spaces traversed by a falling body might increase in proportion to the natural numbers... Baliani's argument embodied an important step toward the concept of mass and the analysis of acceleration, but it was widely misunderstood as intended to contradict the law that both he and Galileo had explicitly stated, the spaces traversed by a falling body are as the odd numbers 1, 3, 5 ...' (DSB).
'Born at Genoa in 1582, he was superintendent of the fortress in Savona in 1611 and there performed experiments on the fall of heavy bodies. Galileo began correspondence with him at Salviati's suggestion, and in 1615 he visited Galileo in Florence. He was first to explain the siphon in terms of the weight of air. His book on motion in 1638 discussed free fall, the pendulum, and motion on inclined planes; the second edition in 1646 included fluid motions, on which he had consulted Castelli, and offered an impetus-theory explanation of acceleration in fall' (Drake, Galileo at work p 439).
see DSB I pp 424-5; Carli and Favaro 210; Cinti 117; Roberts and Trent p 20; NUC: MiU NN NNC (and the present copy); OCLC adds California Institute of Technology, the Smithsonian, Linda Hall Library, U.S. Military Academy, Brown, and University of Wisconsin
£7500
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