arguments seemed unanswerable, and had been received, with Ptolemy's theory, till they had become almost an article of faith. It required a courage which we can only weakly comprehend at this day for a student to fly in the face of the world, of science and religion, and take the solar system to pieces, to put it together again, and to say, after all, that it is the earth which moves and not the sun. Copernicus was slow in venturing before the public with his theory. He began the formulation of his system in 1507; but he wisely determined to make thorough work of the matter, and publish nothing that he could not support with carefully considered argument and evidence. He would not be satisfied with reconciling general appearances with his theory; he would go into details and show how it fitted individual phenomena. He would show how all the movements of the heavenly bodies could be accounted for and predicted by it; even how those phenomena which had hitherto proved unaccountable, the stationary positions and retrograde motions of the planets, and the precession of the equinoxes, found explanation in it. In the mean time reports had got into circulation respecting his new theory, and the public wanted to know what it was. Astronomers were waiting for it, and he was urged to publish it. But he delayed, revising his sheets daily for the insertion of corrected data, and adding new results; and he shrank from the inevitable conflict with the prejudices of the day. These prejudices were already beginning to make their mark. Men of science could accept his views or give them utterance, so far as they had been made acquainted with them, but the general public was against them. He was ridiculed in a comedy; but his gravity and self-restraint carried him safely through all these trials. At last he permitted his friends to publish the work, which he dedicated, in deprecation of clerical censure, to Pope Paul III, in order, as he said in the dedication, that no one should accuse him of running away from the judgment of enlightened men, and that the authority of his Holiness, if he should approve the work, might secure him against the stings of calumny. "I believe," he also said, "that as soon as what I have written in this book concerning the motions of the earth is known, a cry of shame will be raised against me. I am, further, not so much in love with my ideas as to be careless of what others might think about them. And, although the thoughts of the philosopher differ from the aims of the crowd, because he proposes to seek for the truth, so far as God has given it to human wisdom to do, I am not yet ready to reject entirely opinions which seem to be at variance with mine... . All these motives, together with the fear of becoming—on account of novelty and apparent absurdity—an object of ridicule, had nearly caused me to renounce the enterprise. But some friends—among them Cardinal Schom-
