history of the earth can only be comprehended by studying the present state of things. Pythagoras cleared the way, and made a path for the geologist. He is said by Ovid to have taught as follows:— “Nothing perishes in this world, but things simply vary and change their form. To be born means simply that a thing begins to be something different from what it was before; and dying is ceasing from being the same thing. Solid land has been converted into sea. Sea has been changed into land; marine shells lie far distant from the deep, and the anchor has been found on the summit of the hills. Valleys have been excavated by running water, and floods have washed down hills into the sea. Marshes have become dry ground. Dry lands have changed into stagnant pools. During earthquakes some springs have been closed up, and new ones have broken out. Rivers have deserted their channels, and have been reborn elsewhere; as the Erasinus, in Greece, and Mysius, in Asia. The waters of some rivers, formerly sweet, have become bitter, as those of Anigrus, in Greece. Islands have become connected with the main land, by the growth of deltas and new deposits. Peninsulas have been divided from the main land, and have become islands, as Leucadia; and according to tradition, Sicily, the sea having carried away the isthmus. Land has been submerged by earthquakes. The Grecian cities of Helice and Burris, for example, are to be seen under the sea, with their walls inclined. Plains have been upheaved into hills by the confined air seeking vent, as at Trœzene, in the Peloponnesus. There are streams which have a petrifying power, and convert the substances which they touch into marble. Volcano vents shift their positions. There was a time when Etna was not a burning mountain, and the time will come when it will cease to burn; whether it be that some caverns be closed up by the movements of the earth and others opened, or whether the fuel is finally exhausted.” Of course there are several errors in these statements, and especially those which relate to the causes of volcanic vents are absurd. Pythagoras also noticed the changes in the animal kingdoms, such as the metamorphoses of insects. Besides being a naturalist this great man taught some most extraordinary doctrines for his time of the world and nation. He stated that virtue was with him and his followers, a harmony, unity, and an endeavour to resemble the Deity. The whole life of man should be an attempt to represent, on earth, the beauty and harmony displayed in the order of the universe. The mind should have the body and the passions under perfect control; the gods should be worshipped by simple purifications and offerings, and above all by sincerity and purity of heart. Pythagoras, by his good teaching and example, established a great school of philosophy, which influenced the world subsequently in a marked manner. A political riot dispersed his followers, and he died about 504 B.C.