CH. X. CONCLUDING REMARKS. 83 they wished really to understand the laws of the Great Creator. This, in itself, was a great advance; but beyond this Copernicus, by his new system, had opened the way for grand astronomical discoveries which you will see followed quickly in the next century, and Tycho, by his long and patient observations, had stored up facts for the use of those who came after him. In the same way Vesalius in anatomy, and Gesner and Cæsalpinus in natural history, had laid a foundation for the regular study of living beings, and had roughly sketched out a plan of classification. In the subject. of light, Porta had invented the camera obscura, explained the principle upon which it acts, and in doing this had made important discoveries about the action of light upon our eye, and the use of lenses, or convex and concave glasses, in magnifying objects. Lastly, Galileo had discovered the principle of the pendulum and the rate of falling bodies, and was now on the brink of the discovery of the telescope and all the wonders which it has revealed. Meanwhile the sixteenth century closed with one very sad event, which must be mentioned here. Giordano Bruno, a Dominican friar, who was born about the year 1550, at Nola, in Italy, was one of the first people who openly taught that the Copernican system was true. He ought to be peculiarly interesting to us, because he was the first person to teach in England that the earth moves round the sun. But poor Bruno was a very plain outspoken man, and his bold language brought him to a sad but noble death. When people said he should not spread the Copernican system because it was contrary to the Bible, he answered boldly that the Bible was meant to teach men how to love God and live rightly, and not to settle questions of science. Most people now would say that Bruno was right, but the judges of the Inquisition did not think so, and were so alarmed at his opinions that they condemned him to death. In the year 1600, just after the century closed, Bruno was burnt at the stake in Rome as an atheist, partly because he insisted on repeating that the earth is not the centre of the universe, and that there may be other inhabited worlds besides ours. Chief Works consulted. -Whewell's 'Inductive Sciences;' Brewster's 'Optics;' Brewster's Martyrs of Science,' 1874; Encyclopædia Britannica,' art. Astronomy;' Drinkwater's Life of Galileo;' Rossiter's 'Mechanics,' 1873; Cuvier, 'Histoire de Sciences Naturelles;' Baden Powell's 'Natural Philosophy.' CHI. XI. GALILEO. 87 CHAPTER XI. SCIENCE OF THE SEVENTEENTH CENTURY. Astronomical discoveries of Galileo-The Telescope--Galileo examines the Moon, and discovers the Earth-light upon it—Discovers Jupiter's four Moons-Distinguishes the Fixed Stars from the Planets-The phases of Venus confirm the Copernican theory-Galileo notices Saturn's Ring, but does not distinguish it clearly-Observes the spots on the Sun-The Inquisition force him to deny the movement of the Earth-Blindness and Death of Galileo. Astronomical Discoveries of Galileo, 1609–1642.-The seventeenth century was not many years old when Galileo startled the world with discoveries such as had never been heard of before. He relates that when quite a young man he was so struck with an account given by some of his companions of a lecture on the Copernican theory, that he determined to study it, and he soon became convinced of its truth. Nevertheless he saw how difficult it would be to prove that the earth moves round the sun, and not the sun round the earth. When he went to Padua he gave a great deal of time to the study of astronomy, and had already made some remarkable observations, when one day, in the year 1609, being in Venice, he heard that a Dutch spectacle-maker had invented an instrument which made distant things appear close at hand. This discovery, which Bacon and Porta had foreseen, was made at last almost by accident in Holland, by two spectacle-makers, Zacharias Jansen and Henry Lippershey, |