BORELLI, GIOVANNI ALFONSO(b. Naples, Italy, January 1608; d. Rome, Italy, 31 December 1679), astronomy, epidemiology, mathematics, physiology (iatromechanics), physics, volcanology.

    in law and medicine. We can guess that on this trip Borelli stopped in Naples to see Marco Aurelio Severino, perhaps renewing an old association. He must have visited Castelli in Rome. We know that he visited Tuscany, but unfortunately too late to see Galileo. But he did spend some time in Florence, and while there he met both Viviani and Prince Leopold, the youngest brother of the grand duke. After Florence he went on to Bologna where he very favorably impressed Bonaventura Cavalieri. Then he was off to Padua and eventually Venice where he planned to catch a ship back to Messina. Among the topics of discussion in Florence must have been the work of Santorio, for in Venice he bought a copy of De statica medicina and mailed it back to Viviani along with other items of scientific interest. By 1643, then, even though he had not yet published, he was beginning to be known in Italy, and what evidence we have indicates that he had already exposed himself to the studies that were to concern him for the rest of his life: mathematics, physiology, and planetary astronomy.

From 1643 to 1656 Borelli remained in Sicily, so far as we know; he published two works and possibly had a hand in a third. The first developed out of a dispute that may have had some polemic roots in the political and intellectual rivalry between Messina and Palermo. In 1644 a Pietro Emmanuele of Palermo published a Lettera intorno alla soluzione di un problema geometrico. This was attacked, so he followed it a year later with a Lettera in difesa di un problema geometrico. In the second, at least, Borelli's reputation was impugned, and Borelli replied in the Discorso del Signor Gio: Alfonso Borelli, accademico della Fucina e professore delle scienze matematiche nello Studio della nobile città di Messina, nel quale si manifestano le falsità, e gli errori, contenuti nella difesa del Problema Geometrico, risoluto dal R. D. Pietro Emmanuele (Messina, 1646). The Fucina also reacted to protect both itself and Borelli by encouraging the publication of several pamphlets. In one of them, Daniele Spinola's Il Crivello (Macerata, 1647), the resolution of the original problem was provided by Giovanni Ventimiglia, a student and a friend of Borelli.

As this controversy died down, Sicily was invaded by an epidemic of fevers. Messina was especially hard hit and the senate encouraged its local dotti to try to discern its causes. One study that resulted was Borelli's On the causes of the malignant fevers of Sicily in the years 1647 and 1648 . . .; to which he added a section entitled And at the end the digestion of food is treated by a new method (Cosenza, 1649). During his investigation of the epidemic Borelli had visited other cities, observed autopsies, and noted in detail the circumstances under which the disease was prevalent. He concluded that in no way were the fevers caused by meteorological conditions or astrological influences, but were probably caused by something getting into the body from the outside. Since this thing seemed to be chemical, Borelli prescribed a chemical remedy, sulfur, and for this recommendation he acknowledged the counsel of his friend and colleague Pietro Castelli (d. 1661). In the addendum he again disclosed a chemical approach; he characterized digestion as the action of a succo acido corrosivo turning food into a liquid form. Borelli would repeat and expand this particular inquiry during his stay in Pisa.

In 1650 Borelli was considered for the chair of mathematics at Bologna. Cavalieri had died in 1647 and the authorities there wished to fill the post with someone equally able. Accordingly they made inquiries concerning Borelli and received strong endorsements for him as the best mathematician in Italy after Cavalieri. They also learned that Borelli was a trifle capricious and had a leaning toward the “moderns,” Copernicus and Galileo (il Gubernico et il Galileo). Whether or not this latter was a factor, Borelli was passed over and the chair went to Gian Domenico Cassini. So Borelli remained in Messina and was there when Maurolico's Emendatio et restitutio conicorum Apollonii Pergaei was finally published in 1654. The original of the Conics of Apollonius had contained eight books, but the sixteenth century possessed only the texts of the first four. Maurolico had attempted to reconstruct Books V and VI. The extent of Borelli's connection with this project is not certain. We do know that he had composed a digest of the first four books before he left Messina. On this account alone he would have been prepared for an opportunity that presented itself when he later arrived in Pisa. Sometime previously the Medici had acquired an Arabic manuscript which seemed to contain all the original eight books. As early as 1645 Michelangelo Ricci had corresponded with Torricelli about the possibility of translating and publishing it, but with no results. Somehow Borelli had learned of it, however, for just a month after his inaugural lecture at Pisa, in the spring of 1656, he wrote to Leopold suggesting that with the aid of someone who knew Arabic he could edit these “most eagerly awaited” last four books. This led, in 1658, to a long summer's collaboration in Rome with the Maronite scholar Abraham Ecchellensis during which the two substantially completed an edition of Books V, VI, and VII. (It turned out that Book VIII was missing from the manuscript.) After many frustrating delays the work finally saw print in 1661 along with an