GALILEO. 69 



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 Eome 

 maintaining that the comets were heavenly bodies (as they are). 

 Galileo induced one of his pupils to reply to Grassi, and himself cor- 

 rected 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 II Sag- 

 giatore (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 Eiccardi,* 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 in- 

 terests of the papacy were, or seemed to be, involved. His accession 

 was hailed by Galileo's friends, and II 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. 



