Now at the time of Galileo the accepted opinion was that the earth stood still, and that the sun and all the planets revolved round the earth. This opinion the professors and philosophers of the time sought to justify by quoting the Holy Scriptures, pointing out such a passage, for instance, as that in which Joshua is said to have commanded the sun to stand still. Galileo replied that the Bible was intended as a guide in religious matters, but not as a text-book of science, and that the only method of arriving at truth in science was by carefully observing the phenomena and seeking for their most reasonable explanation. However, he was faced with a strong opposition. Some of the enemies refused to believe their eyes, saying that although the telescope was useful in observing objects on land or sea, it was misleading when pointed at the stars. Others refused to look through it at all. [Illustration: Fig. 29.--The Earth in Space.] About one of these objectors Galileo wrote to his friend Kepler, “Oh, my dear Kepler, how I wish that we could have one hearty laugh together! [Illustration: Fig. 30.--Galileo’s Pendulum Clock.] Here at Padua is the principal professor of Philosophy, whom I have repeatedly and urgently requested to look at the moon and planets through my glass, which he obstinately refuses to do. Why are you not here? What shouts of laughter we should have at this glorious folly! And to hear the professor of Philosophy at Pisa labouring before the Grand Duke with logical arguments, as if with magical incantations to charm the new planets out of the sky.” At length the enemies of Galileo denounced him in Rome, and Galileo was called before the Inquisition to answer for his strange doctrines. The court before which he was judged decided that his doctrines were contrary to divine revelation, and threatened him with torture if he should continue to teach them. Galileo had no choice but to renounce his doctrine that the earth moved round the sun, and to do penance for having taught it. He was now seventy years old, and although he was allowed to return to his home his useful work was nearly at an end. He devoted the remainder of his days to Mathematics and to the invention of the pendulum clock, as already stated. The centuries which succeeded Galileo have fully justified him and his teachings. The idea that the earth moved round the sun is now completely established, and is universally accepted by all educated people. Not only that, but science is now free to pursue its course without regard to the errors and prejudices of the old schools of Philosophy. It is now recognised that no artificial limits can or must be put in the way of the march of the human intellect, and that the increase of knowledge makes invariably for the increased happiness of mankind. CHAPTER VI THE BAROMETER