In the same year, 1619, a Jesuit, Father Grassi, delivered a lecture on the three comets in the Roman College, in which he gave out that such phenomena were not mere appearances, but real heavenly bodies; copies of this lecture were widely circulated, and Galileo was strongly urged by his adherents to publish his opinion. He was prudent enough to evade for the time a fresh controversy, which, in the existing critical state of affairs, might bring him into danger, and apparently took no part in the scientific feud which was brewing. But he induced his learned friend and pupil, Mario Guiducci, consul of the Academy at Florence, to publish a treatise on comets. Numerous alterations and additions, however, which are found in the original MS. in the Palatina Library at Florence, attest that he had a direct share in the editorship.[164] The opinions hitherto held by philosophers and astronomers on this subject were discussed, and the author’s own—that is Galileo’s—expounded. Grassi’s views were sharply criticised, and he was reproachfully asked why he had passed over Galileo’s recent astronomical discoveries in silence. Grassi, who recognised the real originator of the work, in the reply which he issued a few months later entirely ignored the pupil, that he might the more vigorously attack the master. Under the pseudonym of _Lothario Sarsi Sigensano_, he published a pamphlet against Galileo, entitled, “The Astronomical and Philosophical Scales.”[165] It is written with caustic bitterness, and is a model of Jesuitical malice and cunning. The comet question was for the time a secondary matter with Grassi, and he begins with a personal attack on Galileo, by disputing the priority of several of his most important discoveries and inventions, and reproaching him, with pious indignation, with obstinate adherence to a doctrine condemned by theologians. Up to this point he is only angry and spiteful, but as he goes on he becomes cunning. He sets up for a warm defender of the Peripatetic physics, and attacks the Copernican system, and its advocate Galileo, to compel him either to ignominious silence or dangerous demonstrations. Under pretext of meeting Guiducci’s reproach that he (Grassi) had taken Tycho as his authority, he asks whether it would have been better to follow the system of Ptolemy, which had been convicted of error, or that of Copernicus, which every God-fearing man must abhor, and his hypothesis, which had just been condemned? In discussing the causes of the movements of comets, it seemed to him that the arguments were insinuated on which the forbidden doctrines were based. “Away!” he exclaims in righteous indignation, “with all such words so offensive to truth and to every pious ear! They were prudent enough certainly scarcely to speak of them with bated breath, and not to blazon it abroad that Galileo’s opinion was founded upon this pernicious principle.”