a famous Greek philosopher, a friend or pupil of Thales, was born at Miletus in the 42d Olympiad, in the time of Polycrates, tyrant of Samos, 610 B.C., and died at the age of 63. He was the first who publicly taught philosophy, or wrote upon philosophical subjects, and carried his researches very far into nature. It is said that he discovered the obliquity of the zodiac, was the first who published a geographical table, invented the gnomon, and set up the first sun-dial in an open place at Lacedemon. The primary essence he held to be infinite (ἀπόρρητος), all-embracing, and divine; that this infinite always preserved its unity, but that its parts underwent changes; that all things came from it; and that all returned into it. According to all appearance, he meant by this obscure and indeterminate principle the chaos of the other philosophers. He asserted that there is an infinity of worlds; that the stars are composed of air and fire, which are carried in their spheres, and that these spheres are gods; and that the earth is placed in the midst of the universe, as in a common centre. He added, that infinite worlds were the product of infinity, and that corruption proceeded from separation.