measurement, as determined, was not very wide of the truth. Precise accuracy was impossible, because several of the data involved were imperfect, but, in any event, the principle was a correct one. An actual measurement of the globe on which we live had been made.
All this happened in the third century b.c. It is curious to reflect that sixteen or seventeen hundred years later the most cultivated intellects of Europe, far from having advanced upon this measurement of Eratosthenes, were disputing as to whether the earth is round at all. It must be recalled also, however, that a certain number of minds in each generation held to the teaching of the old Greeks. Columbus was by no means alone in the faith that the Indies could be reached by sailing out to the west. His great merit was that he had the courage of his convictions. Yet, beyond question, Christendom as a whole was far more amazed when Columbus returned with demonstrative evidence of the truth of the theory, than the Greek world would have been had a similar demonstration been presented in the day of Eratosthenes, or at any time within several succeeding centuries.
Let us turn to another field of science and ask what conception the Greek held of the origin of the world. We are met with a somewhat mystical answer. Doubtless the conceptions themselves were vague; the language is correspondingly so. Yet here and there we encounter an idea of greater clearness, and in the end we are not left greatly in doubt as to the trend of general opinion. The idea of growth of development in connection with the universe came early to these thinkers. This was perhaps particularly true of the Ionian philosophers in Asia Minor—Anaximander and Anaximenes, Heraclitus and Anaxagoras. We have seen that the last-named philosopher believed the sun to be a molten mass, and the moon an earthy body, and that he was probably led to this opinion through study of meteorites, and particularly of the very famous one that fell at Ægespotomi. Pondering the fall of this body, Anaxagoras was led to the conception of a vortex motion through which the heavenly bodies are kept out in space. A stone whirled about the head in a sling would give full warrant to the idea that centrifugal force could hold the whirled body out in space. If the motion of the string or the hand slackens, the stone in the sling falls. So it is, said Anaxagoras, with the whirling bodies in space. If their motion is retarded they must fall back to earth as meteorites are observed to do. That idea grasped, it was but a step to the assumption that the earthlike bodies up in the heavens—the sun, the moon, the planets—had been projected out into space in the time of world-making. This implies a whirling motion of the earth itself; but we have already seen that the Pythagoreans had propounded that idea a half-century before the time of Anaxagoras. Here then is the conception of a primordial mass of molten matter which throws off the sun, the moon, and planets by centrifugal force, an idea which surely contains the germ of the nebular theory of Kant and La Place. Nor is this all. Anaxagoras distinctly states that matter becomes changed into stone through cooling. Accept this statement with the conception that the sun is still molten, but that the moon like the earth is cool and inhabited (which Anaxagoras is alleged by Dionysius to have asserted), and we have the entire modern theory of earth-formation pretty distinctly outlined. The man who thus anticipated La Place came from Asia Minor to Athens in the Golden Age of the fifth century b.c.
At an even earlier day there lived in Asia Minor a philosopher who appears to have guessed out a curiously illuminative idea of the origin of man himself. This was Anaximander, the pupil of Thales, and therefore one of the earliest of Greek thinkers. Only a few words of the writings of Anaximander are preserved, and his opinions therefore are known to us only at second hand. But he held at least one theory, which as vouched for by various copyists and commentators entitles him to be considered perhaps the first teacher of the idea of organic evolution. According to the idea of Anaximander, man developed from a fishlike ancestor, "growing up as sharks do until able to help himself, and then coming forth on dry land." It is well known that the Greek philosophers of Asia Minor
