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Homocentrica. Euisdem de causis criticorum dierum per eaque in nobis sunt.
[Venice, no publisher] 1538 - 4to (202 x 147 mm), ff [4] 78 [misfoliated 73], with fine woodcut portrait of Fracastoro on verso of *4 and numerous woodcut diagrams in text; contemporary manuscript annotations (see below), old paper repair to inside lower blank corner of title, a crisp, large copy recased in old vellum. First edition of the Homocentrica, famous for containing the first printed description of the telescope, with a woodcut illustrating two lenses and rays of light. It is also prepared the way for the Copernican theory by calling into question the epicycles and eccentrics of the Ptolemaic hypothesis. 'For Fracastoro the only valid [method] is that of experience, as he does not hesitate to declare in the Homocentrica . (1538), a work on astronomy in which the movements of the heaves and the celstial spheres with their orbits, the seasons,and the various types of days (civil, solar, sidereal) are illustrated, and in which Fracastrolo again reinstates in place of honor the most ancient system of astronomical theory, the Eudoxian. Apart from the intrinsic value of the work, its attempts to solve certain problems in astronomical and terrestrial physics are interesting, as are the studies on refraction. In the course of the latter Fracastoro points out the apparent enlargement and approach of celestial objects (as well as the moon) observed through two superimposed lenses, analogous to the appearance of a body immersed in water, which vries exactly according to the quantity and density of the water itself' (DSB).After having studied at the University of Padua [Fracastoro] held a professorship of logic there from 1501 to 1508, and as Copernicus studied at Padua from the autumn of 1501 for some years, there can hardly be any doubt that the two young men, both interested in astronomy and medicine, must have known each other at Padua, and possibly may have discussed with each other the difficulties of the Ptolemaic system. In 1508 Fracastoro went back to Verona, where he spent the rest of his life till his death in 1553, devoting himself to medicine, astronomy and poetry. His principal work, Homocentrica, appeared at Venice in 1538 .'At Padua Fracastoro had been on friendly terms with three brothers, Della Torre, one of whom is known as the collaborator of Leonardo da Vinci in his studies on anatomy, while another, Giovanni Battista, devoted himself specially to astronomy and designed a plan of representing the motions of the planets without excentrics and epicycles, using solely homocentric spheres. He died at an early age, but on his deathbed he begged Fracastoro to work out his ideas into a new astronomical system; and in fulfilment of the promise given on that occasion Fracastoro prepared his work Homocentrica, without, however, following strictly the methods of Della Torre' (Dreyer, A History of Astronomy from Thales to Kepler pp 296-298).Although based on the homocentric model of the Greek astronomers and philosophers Eudoxus and Calippus, Fracastoro rearranges this system so that all spheres 'have their axes at right angles to each other. He shows how every motion in space can be resolved into three components at right angles to each other, while conversely three motions at right angles will produce "motions in longitude as well as in latitude." He assumes that an outer sphere may communicate its motion to an inner one, while an inner one does not influence an outer one, and he is therefore able to let the Primum Mobile communicate its daily rotation to all the planets without having with Eudoxus to assume one sphere for each planet to produce the daily rotation. A set of spheres generally consists of five spheres which he calls (beginning with the outermost) circumducens, circitor, contravectus, anticircitor, and ultimus contravectus, of which the fourth and fifth revolve in opposite directions to respectively the second and third, and generally with different velocities' (ibid).Fracastoro's friend Titian painted his portrait; it is now i [Attributes: Soft Cover]
      [Bookseller: WP Watson Antiquarian Books]
Last Found On: 2017-02-28           Check availability:      AbeBooks    


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