October of the same year was called to the chair of mathermatics at this university, reports in a letter of 6th November,[1] in which he tells Galileo what reception he had met with from the heads of the college, that the proveditor of the university, Mgr. D'Elci, had expressly forbidden him at his first interview to treat in his lectures of the double motion of the earth, or even take occasion in any digression to mention it as probable!
An accidental circumstance, however, was the immediate cause of turning the controversy into the channel which proved so fatal to Galileo. One day in December, 1613, Castelli and several other learned men were guests at the Grand Duke's table at Pisa, where the court was then staying. The conversation turned chiefly on the remarkable phenomena of the Medicean stars, whose veritable existence in the heavens Boscaglia, professor of physics at the university, was constrained with a heavy heart to confirm in answer to the question of the Grand Duke's mother, Christine. Castelli eagerly seized the opportunity of applauding Galileo's splendid discovery. Boscaglia, a Peripatetic of the purest water, could not master his displeasure, and whispered meanwhile to the Grand Ducal mother that all Galileo's telescopic discoveries were in accord with the truth, only the double motion of the earth seemed incredible, nay impossible, as the Holy Scriptures were clearly opposed to it. The repast was then over, and Castelli took leave, but he had scarcely left the palace when he saw Christine's porter hastening after him and calling him back. He obeyed, and found the whole company still assembled in the Grand Duke's apartments. Christine now began, after a few introductory remarks, to attack the Copernican doctrines, appealing to Holy Scripture. Castelli at first made some humble attempts to avoid bringing the Bible into the controversy; but as this was of no avail he resolutely took the theological standpoint, and defended the modern views of the universe so impressively and convinc-
- ↑ Op. viii. pp. 290, 291.
