upon us when we remember that the science of this treatise of Galileo's is quite erroneous. It denies that the moon controls the tides. The treatise was not published. It was shown in MS. to a few trusted friends, but the ideas here set forth were developed in Galileo's Dialogues published in 1632.
In 1618 three comets appeared in the sky. Galileo communicated his views of their nature to a few friends. He considered them to be merely atmospheric appearances which rise far beyond the moon, to be sure, and not heavenly bodies. The conclusion was erroneous, of course. In 1619 the Jesuit Father Grassi delivered a lecture in Rome maintaining that the comets were heavenly bodies (as they are). Galileo induced one of his pupils to reply to Grassi, and himself corrected the MS. work so that its severe criticisms of the Jesuit (who was, after all, defending a true thesis) are Galileo's own. A reply was written by Grassi in which Galileo is personally attacked and the Copernican system assailed. Galileo's answer is the famous Il Saggiatore (the assayer) which was printed October, 1623. It was brilliantly, but very carefully written, and before it was published it passed from hand to hand among Galileo's friends, who purged it of every phrase likely to be dangerous. The imprimatur was given on a report of Father Riccardi,[1] a former pupil of Galileo's, of whom we shall hear more.
In July Pope Gregory XV. died and was succeeded by Urban VIII. who, as Cardinal Maffeo Barberini, had for many years been one of Galileo's strongest supporters. A new era seemed to open with his accession. His many letters to Galileo had always been friendly, often cordial. In thanking Galileo for his letters on solar spots (1613) the cardinal had written: "I shall not fail to read them with pleasure, again and again, which they deserve. . . . I thank you very much for your remembrance of me, and beg you not to forget the high opinion that I entertain for a mind so extraordinarily gifted as yours." In 1620 the cardinal composed a poem in Galileo's honor and sent it to him as a 'proof of great affection.'
During the progress of Galileo's affair with the Holy Office in 1615 and 1616, the cardinal stood his friend and believed that it was chiefly to his own efforts that an issue so satisfactory to the astronomer personally was brought about. He was a friend to Galileo; he was not a believer in the Copernican doctrine; he made no efforts to prevent its condemnation. He proved to be inexorable where the interests of the papacy were, or seemed to be, involved. His accession was hailed by Galileo's friends, and Il Saggiatore was dedicated to him, and he accepted the dedication. The book is considered a model of
- ↑ Riccardi had been convinced that the Ptolemaic theory was false and had accepted in its place not the theory of Copernicus, but that of Tycho Brahe.
