opponents, who, feeling that they could not successfully fight him on his own ground, had entrenched themselves behind an unassailable bulwark, Galileo proceeds to discuss the well known passage in Joshua which the Aristotelians were fond of adducing to demonstrate the contradictions between the modern views and Holy Scripture. His object is to beat his adversaries with their own weapons, by showing that if this passage is taken literally, and God really arrested the sun in his course in answer to Joshua's prayer, and thus prolonged the day, it makes the incorrectness, nay the impossibility, of the Ptolemaic system quite clear, while the Copernican agrees with it very well. According to the Ptolemaic ideas, Galileo goes on, the sun has two motions, the annual one from west to east, and the daily one from east to west. Being diametrically opposed to each other, they cannot both be the sun's own motions. The annual motion is the one which belongs to it; the other originates in the primum mobile, which carries the sun round the earth in twenty-four hours and occasions day and night. If therefore God desired to prolong' the day (supposing the Ptolemaic system to be the right one) He must have commanded, not the sun but the primum mobile, to stand still. Now, as it is stated in the Bible that God arrested the sun in its course, either the motions of the heavenly bodies must be different from what Ptolemy maintained them to be, or the literal meaning must be departed from, and we must conclude that the Holy Scriptures, in stating that God commanded the sun to stand still, meant the primum mobile, but, accommodating themselves to the comprehension of those who are scarcely able to understand the rising and setting of the sun, said just the opposite of what they would have said to scientifically educated people. Galileo also says that it was highly improbable that God should have commanded the sun alone to stand still, and have allowed the other stars to pursue their course, as all nature would have been deranged by it without any occasion, and his belief was that God had enjoined a temporary rest on the
