Astronomical Images : 'Place and motion of the Earth' in the purported Cartesian world system

Vincenzo Maria Coronelli

Astronomical Images

<p style='text-align: justify;'>In his <i>Atlante veneto</i> of 1690, Vicenzo Coronelli (1650-1718) included a discussion of the world systems of Ptolemy, Copernicus, and Tycho Brahe. Accompanying this discussion of the 'Sistemi del mondo' were nine figures, presented together on a single bifolium (Plate 9); these figures were later reproduced in Coronelli's <i>Epitome cosmografica</i> (1693), where they were each printed onto a separate sheet. Figures VIII and IX comprise Coronelli's attention to the Cartesian world system. However, these two illustrations bear strikingly little resemblance to the Cartesian vortices of Descartes' <i>Le monde</i>. Figure IX, seen here, offers 'observations on the system of Descartes concerning the place and motion of the Earth.' The heliocentric system is similar to that presented in Figure VIII, but displays in addition the orbital paths of Mercury and Venus. While there is a suggestion of <i>something</i> emanating from the Sun and filling the space between it and the orbit of Mercury, it is far from clear what this is; it is only in the text that Coronelli provides any indication of the more familiar components of Cartesian cosmology, referring to a fluid, space-filling heavenly matter that supports the planets and moves them in their orbits, just as a man in a boat is moved by sails or oars. The inclusion of planetary models in these cosmographical works reflects the development of the genre in the early modern period. In attempting to describe the Earth in relation to the heavens, cosmographical texts often borrowed from the diagrammatic tradition of medieval spherical astronomy; for instance, the nested-sphere diagrams representing the heavens and the terrestrial Elements according to Aristotle. Planetary models, however, typically belonged to the tradition of <i>Theorica planetarum</i>; the depiction of world systems in Coronelli's texts therefore reflects the increasing scope of cosmography to include elements of planetary as well as spherical astronomy.</p>