To the annoyance of Galileo’s opponents and delight of his friends, by the end of October, 1623, “Il Saggiatore” appeared. This work is a masterpiece of ingenuity; for the author not only dexterously avoids falling into the snares laid for him by Father Grassi, but prepares signal defeats for him. Galileo takes his attack on him, “The Astronomical and Philosophical Scales,” paragraph by paragraph, throws light on each, and disputes or confutes it. And it is done in so sparkling and spirited a style, and the reasoning, pervaded by cutting sarcasm, is so conclusive, that “Il Saggiatore” certainly deserves to be called a model of dialectic skill. Our limits preclude going further into its scientific contents. For our purpose it will suffice to say that Galileo took occasion in it to lash many errors in Grassi’s work unmercifully, and thereby incurred the eternal hatred of the all powerful Jesuit party. Thus it was to a great extent the purely scientific “Saggiatore” which subsequently conjured up the tragic element in Galileo’s fate. Another interesting point in the work is the way in which Galileo replies to Grassi’s interpellations about the system of the universe. Admirable as is the ingenuity with which he performs this ticklish task, one cannot sympathise with the denial of his inmost convictions. He parries the provocations of his adversary by demonstrating that the Ptolemaic and Copernican doctrines had nothing to do with the controversy about comets, and that this question was only raised by “Sarsi” in order to attack him (Galileo). He adds the ambiguous remark: “As to the Copernican hypothesis, I am fully convinced that if we Catholics had not to thank the highest wisdom for having corrected our mistake and enlightened our blindness, we should never have been indebted for such a benefit to the arguments and experiences of Tycho.”[183] He then shows that the Copernican system, “which, as a pious Catholic, he considers entirely erroneous and completely denies,” perfectly agrees with the telescopic discoveries, which cannot be made to agree at all with the other systems. But since, in spite of all this caution, a defence of the new system might have been detected in these statements, Galileo hastens to the conciliatory conclusion, that since the Copernican theory is condemned by the Church, the Ptolemaic no longer tenable in the face of scientific research, while that of Tycho is inadequate, some other must be sought for.