Thales, a Greek philosopher, and one of the seven wise men, born in Miletus, Ionia, about 636 B. C, died probably about 546. He took an active part in the political affairs of his native country. Ue visited Crete and Egypt, and acquired in the latter country an acquaintance with geometry. Various physical discoveries are attributed to him. He measured the height of the Egyptian pyramids by observation of the time at which a shadow equalled in length the height of the object; and he is said to have computed the sun's orbit,' to have fixed the length of the year at 365 days, and to have been the first among the Greeks to predict eclipses, though very vaguely. Aristotle calls him the originator of the Ionic natural philosophy, and hence, indirectly, of Greek philosophy in general. Ho taught that all things are instinct with life, and originate from water. The writings attributed to him were declared spurious in antiquity, and his sayings recorded by Aristotle and Diogenes Laertius are probably conjectural.