celebrated philosopher of Ephesus, in Asia Minor, flourished about b.c. 503, in the reign of Darius, son of Hystaspes. Of his personal history we know nothing more than that he was the son of Blyson, attended the lectures of the philosophers Hippasus and Xenophanes, and made a particular study of the doctrines of the Pythagoreans. Heraclitus was one of those spirits whose eye was formed so as to view only the miseries of human life, and who gave vent to their sensibility by tears, as Democritus did by laughter. He was usually called the Weeping Philosopher. He was a voluminous writer, but his most esteemed work was a treatise on nature, which, however, was so obscure, that he obtained the surname of Σκοτοφάγος. It is said that Euripides sent this work to Socrates, and that the philosopher having read it, remarked that all he could understand was very good, but that much of it was unintelligible. Heraclitus retired from intercourse with men to some deserted spot, where he could pursue without interruption his philosophical speculations; but his austere mode of living brought on a dropsy, and finding no relief, he determined to destroy himself by fire, and thus perished in his sixtieth year. Others say that he was devoured by dogs. Heraclitus regarded fire as the beginning and end of all things, as a matter subtile, eternal, unalterable, and ever moving. The less subtile portions of fire produced air, those of air generated water, and from this again was formed earth. The soul he considered as an igneous substance, or an exhalation (ἀναβαίνων). He was in fact a materialist, and admitted only body, form, and motion. Every thing was only a change of body, death only a change of form. This treatise was first published by Crates, and put into Greek verse by Scythinus. Some fragments of it which remain have been published by Stephens, with other pieces, in a work entitled Poësis Philosophica, Paris, 1573. Also Fragmenta et Literae, Gr. et Lat. ed. Lubin, Rostock, 1601. See likewise De principio rerum naturalium ex mente Heracliti physici exercitatio, Lips. 1697; De rerum naturalium genesi ex mente Heracliti Heraclius physicus dissertation, Lips. 1702.