d. At this dinner the discussion centered on floating bodies. Galileomaintained that bodies can float only if their specific gravity is less than that of water. Among thedinner guests there were, however, some followers of Aristotle's philosophies, and they arguedthat bodies float if their shape is wide and smooth so they cannot cut through the resistance of thewater. Floating bodies were a topic on which Galileo was especially knowledgeable, as he hadbeen interested in the subject since, when as a student, he had read Archimedes. He was able tosupport his point so brilliantly that one of the guests of honor, Maffeo Cardinal Barberini, sidedwith him. Years later, Cardinal Barberini became Pope Urban VIII and turned against Galileo,becoming one of his bitter enemies, but at that moment he was as congenial as one could be,sincerely admiring Galileo's dialectical skill. Perhaps to please the Cardinal, the Grand Dukeasked Galileo to put his argument into writing, which he did. The result was The Discourse onFloating Bodies.Galileo's sharp, almost sarcastic wit made him especially suited to arguments and debates,of which he was to have many in the following years. Some of these resulted in famous writingsthat added to his lasting glory; many antagonized people of his time and turned many of them into"enemies."The Peripatetics at the Grand Duke's table were not very dangerous as potential enemies,but his next adversary was. Even before the Discourse on Floating Bodies was published in1612, Galileo was engaged in a conflict with an astronomer whose name he did not know and wasnot to find out for over a year -- the Jesuit father Christopher Scheiner (1575-1650). In 1610,Galileo had claimed to be the first discoverer of sunspots; so had Father Scheiner, and the twohad entered into a bitter dispute. Father Scheiner had communicated his opinions on hisobservations of sunspots in several letters to Mark Welser, a German patron of scienc...
