their day's work depended. They learnt at what time in the month the moon was full, so that they could see their way by moonlight; and they remarked very early the times when spring, summer, autumn, and winter came round, because the sowing of their seeds and the gathering of their fruits depended upon these seasons. In this way we find that as far back as history goes men have always had some knowledge of the facts of nature; and those nations, like the Egyptians and Chinese, which long ago had become highly civilized, had learnt a very great deal, and must probably have known some things of which we are still ignorant. There has been a great deal written about the science of the Chinese, Indians, and Egyptians, but I shall not tell you anything about them here, because their knowledge has had very little to do with the science which has come down to us, and it would besides be difficult to give you any real idea of what they knew without writing a book on the subject. We will start, therefore, with the Greeks, at the time when they first began to try and explain some of the natural events which they saw taking place every day. This was about the year 700 B.C., when Thales, one of the seven wise men, was living, and you will see in the next chapter that even at this time, when Greece was famous for its learning, the people had still some very strange ideas about the working of the universe. CH. I. SCIENCE OF THE GREEKS. 7 CHAPTER I. 639 TO 470 B.C. Ignorance of the Greeks concerning Nature-Ionian School of Learning -Thales discovers the Solstices and Equinoxes, and knows that the Moon Reflects the Light of the Sun-Anaximander invents a Sundial-Discovers the Phases of the Moon-Makes a Map of the Ancient World-Pythagoras teaches that the Earth moves, and that the Morning and Evening Star are the same-He studies Geology, and knows that Land has in some places become Sea-True sayings of Pythagoras and his Followers about Geology. ABOUT 600 years before Christ was born, the Greeks were the most learned people in Europe. They were naturally a handsome and clever race, and their young men were trained to be both good soldiers and good scholars. An English boy, if he could be carried back to those days, would find that the young Greeks could read, write, draw, and argue as well as himself, and probably that they could leap, wrestle, and run far better than himself or any of his schoolfellows. But on some points he would find that their ideas were very strange. If he spoke to them of the world as a round globe they would stare in astonishment, and tell him that such an idea was absurd, for everyone knew that the world was flat with the sea flowing all round it. If he asked them, in his turn, about Mount Etna, they would surprise him by replying that the god Vulcan had his smithy underneath the mountain, where he was forging thunderbolts for Jove, and that Etna was the chimney of his forge. But if he spoke of the sun as a globe of light, they would turn away from him in horror as a wicked unbeliever in the gods, for who among the Greeks did not know that the sun was the god Apollo, who drove his chariot every day across the sky from east to west? In fact, the Greeks, though learned and brave, were quite ignorant of what we now call 'natural knowledge;' they did not know that the rising and setting of the sun, and the eruption of a volcano, are things which happen from natural causes; but everything which was not done by man, they thought was the work of invisible beings or gods. It was not long, however, before some wise men began to think more deeply about these things. You will have read in Grecian history how the Greeks, after the taking of Troy, crossed over the Hellespont and founded colonies on the coast of Asia Minor; one of the largest of these colonies was called Ionia, and the Ionians became famous for their learning and wisdom. Thales, 640.-Here Thales, one of the seven wise men of Greece, was born at Miletus, about 640 B.C. Thales travelled in Egypt, and learned many things from the Egyptians, and then returned to his own land and founded a school of learning. He was the first Greek who studied. astronomy, and although, like his countrymen, he believed that the earth was flat and floated on the water, yet he made several great discoveries. The Greeks had always divided their year into two parts only, summer and winter, but Thales discovered that there are four distinct divisions marked out by the sun. He noticed that in the middle of winter the sun, instead of passing overhead, reached at mid-day only a certain low. point in the heavens, and then began to set again, so that |