He also explained that the red sky at sunset was not caused by the reflections from Hell, nor was the sun moved behind a mountain by giant angels at night. Copernicus was a Catholic, as all teachers were, but he had been deceived by the esoteric and the exoteric, and had really thought that the priests and so-called educated men actually desired, for themselves, to know the truth. At Padua he had learned to read Greek, and had become more or less familiar with Pythagoras, Hipparchus, Aristotle and Plato. He quoted these authors and showed how in some ways they were beyond the present. This was all done in the exuberance of youth, with never a doubt as to the value and the beauty of the Church. But he was thinking more of truth than of the Church, and when a cardinal from the Vatican came to him, and in all kindness cautioned him, and in love explained it was all right for a man to believe what he wished, but to teach others things that were not authorized was a mistake. Copernicus was abashed and depressed. He saw then that his lectures had really been for himself--he was endeavoring to make things plain to Copernicus, and the welfare of the Church had been forgotten. He ceased lecturing for a time, but private pupils came to him, and among them astrologers in disguise, and these went away and told broadcast that Copernicus was teaching that the movements of the stars were not caused by angels, and that "God was being dethroned by a tape-measure and a yardstick." Alchemy had a strong hold upon the popular mind, and these alchemists and astrologers were fortune-tellers and derived a goodly income from the people. They had their stands in front of all churches and turned in a goodly tithe "for the benefit of the poor." When the astrologers attacked Copernicus he tried to explain that the heavens were under the reign of natural law, and that so far as he knew there was no direct relationship between the stars and the men upon earth. The answer was, "You yourself foretell the eclipse, and assume to know when a star will be in a certain place a hundred years in advance; now, if you can prophesy about stars, why can't we foretell a man's future?" Copernicus proudly declined to answer such ignorance, but went on to say that alchemy was a violence to chemistry as much as astrology was to astronomy. In chemistry there were exact results that could be computed by mathematics and foretold; it was likewise so in astronomy. Copernicus was philosopher enough to know that astrology led to astronomy, and alchemy led to chemistry, but he said all he wished to do was to eliminate error and find the truth, and when we have ascertained the laws of God in reference to these things, we should discard the use of black cats, goggles, peaked hats, red fire and incantations--these things were sacrilege. And the enemy declared that Copernicus was guilty of heresy in saying they were guilty of sacrilege. Moreover, black cats were not as bad as blackboards.