THEOPHRASTUS, a celebrated Greek philosopher, was the son of Melanthus, and was born at Erebus in Boeotia. He was at first the disciple of Lucippus, then of Plato, and at last of Aristotle. He succeeded the latter in the 322d year before the Christian era, and taught philosophy at Athens with extraordinary applause. He said of an orator without judgment, "that he was a horse without a bridle." He was accustomed to say, "There is nothing so valuable as time, and those who lose it are the most inexcusable of all prodigals." He died at above 100 years of age. Theophrastus wrote many works; of which the following are the principal of those that are still extant, 1. An excellent moral treatise intitled Characters, which he says in his preface he composed at 99 years of age. Isaac Casaubon has written learned Commentaries on this small treatise: it has been translated from the Greek into French, by M. de la Bruyere; it has also T H E been translated into English. 2. A curious treatise on Plants. 3. A history of Stones; of which Dr Hill has given a good edition, with an English translation, and learned notes, in 8vo. THEOPHYLACT, archbishop of Achrida, the metropolis of Bulgaria, and one of the most learned men of the 11th century, was born at Constantinople, where he was instructed in ecclesiastical learning. He laboured with great zeal to establish the Christian religion in Achrida, where there were still many pagans, and died after the year 1071. He wrote Commentaries upon the Gospels, the Acts of the Apostles, St Paul's Epistles, and upon Habakkuk, Jonah, Nahum, and Hosea, and also several Epistles, and other works in Greek. THEOPOMPUS, a celebrated Greek orator and historian, was born in the island of Chios, and flourished in the reign of Alexander the Great. He was one of the most famous of all the disciples of Isocrates, and won the prize from all the panegyrists whom Artemisa invited to praise Mausolus. He wrote several works, which are lost. THEOREM, a speculative proposition, demonstrating the properties of any subject. THEORETIC, something relating to theory, or that terminates in speculation. See THEORY. THEORY,