Democritus, of Abdera, a scholar of Leucippus, who flourished four hundred and fifty-six years before Christ, was the first publisher of the Atomic Cosmogony, invented by Mochus, the Phœnician, said to have been received by his master Leucippus. Both admitted plurality of worlds. Democritus was the first who taught that the milky way is occasioned by the confused light of an infinite number of stars; which doctrine is still maintained by the best informed of philosophers. He also extended that idea to comets; the number of which Seneca says the Greek philosophers did not know; and that Democritus suspected there were more planets than we could see. This was also the opinion of many others, the truth of which has been verified in the discoveries of Pallas, Juno, Vesta, and the _Georgium Sidus_. Democritus is considered as the parent of experimental philosophy; the greatest part of his time was devoted to it; and he is said to have made many discoveries. He, like Meteon, and Newton, maintained the absurd idea of the existence of a vacuum, which was denied by Thales and Descartes. Democritus also maintained that the sea was constantly diminishing. He declared that he would prefer the discovery of one of the causes of the works of Nature, to the possession of the Persian monarchy. Often laughing at the follies of mankind, he was thought by the vulgar to be out of his mind; but Hippocrates, being sent to cure him, soon found him to be the wisest man of the age; and Seneca reckons him the most acute and ingenious of the ancients, on account of his many useful inventions; particularly his ingenious making of artificial emeralds, tinging them of any colour; of softening ivory, dissolving stones, &c. Although the chief attention of Plato and Aristotle was directed to other grand objects, yet they much contributed to the improvement of astronomy. Notwithstanding the most famous in this respect was Eudoxus, the scholar of Plato, who was famous for his skill in astrology, natural and judicial, or the art of foretelling future events by the relative situations of the stars, of their various influences, an art which prevailed for many ages among the ancients, and is yet assiduously cultivated by the modern Arabians and other orientals, although in a great measure exploded in European nations. By the former or which divisions in this science are foretold the changes of seasons, rain, wind, thunder, cold, heat, famine, diseases, &c., from a knowledge of the causes that are believed to act upon the earth and its atmosphere; whilst the latter foretold the characters, fortunes, &c., of men, from the stellary disposition at the moment of their respective nativities.