Institute and Museum of History of Science, Florence, ITALY

Evangelista Torricelli

4. Torricelli's Copernicanism

In 1632 Torricelli was unhesitant in affirming his adhesion to the Copernican system (see "Childhood and adolescence"). But when, in February 1645 the Minim friar Marin Mersenne asked for his opinion on the Aristarcus published in France by Roberval, Torricelli responded that he was unqualified to be interested in the content of the work. Certainly, he did not believe that the author of the book published by Roberval was Aristarchus (the author, as is known, was Roberval himself, not the ancient precursor of Copernicus). But the disapproving refusal to discuss the content of the book gives the impression that Torricelli was not keen to be occupied openly with problems of an astronomical nature.


The Copernican System, Andrea Cellarius, Harmonia macrocosmica…, Amsterdam, 1661
(from F. Bertola, Imago Mundi. La rappresentazione del cosmo attraverso i secoli,
Cittadella PD, Biblos, 1995, p. 162).

Nonetheless, it does not seem that he was completely uninterested in celestial phenomena. We have a demonstration in an account of a voyage to Italy made by the Frenchman Balthasar de Monconys. Monconys met Torricelli during his stay in Florence, in the autumn of 1646. In his Journal, published in Lyon in 1665, he recalled that the Italian scientist spoke to him of the movements of the celestial bodies, explaining "how the bodies turned about their centre, how the Sun, the Earth and Jupiter cause all the ether which surrounds them to turn, the closer parts turning more rapidly than those that are further away, in such a way that experience shows when one turns a stick in the centre of some water, and the same happens to the planets, with respect to the sun; to the moon with respect to the earth; to the Medicean stars with respect to Jupiter [...]" [in Journal des voyages de Monsieur de Monconys, Premiére partie, Chez Horace Boissat,  George Remeus, Lyon, 1665, pp. 130-31] It would seem, thus, that the mathematician of the Grand Duke, despite declaring himself to be only a geometer, did not shirk looking at the sky as an astronomer. Perhaps he was advised not to devote too much of his time to such activities. An index-card noticed by the librarian of the Biblioteca Laurenziana in 1741 refers to "writings and studies of astronomy" by Torricelli. Until now, no trace has been found of these writings.


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