Life of Marcellus, in Parallel Lives. In this the mechanical inventions of Archimedes are described. Polybius. See vol. i., p. 201. In his Histories Polybius describes the mechanical contrivances and war-engines of Archimedes, and also gives an account of his death. Ptolbmy (Claudius Ptolemaeus). See vol. i., p. 269. Geographia (or Almagest of the Arabs). The edition published by Nobbe, in 3 vols., Leipzig, 1842, was one of the best complete editions of the Greek text. The edition published in Didot's Bibliotheca Classicorum Grocorum, Paris, 1883, is excellent. Earlier editions contain many errors. Strabo. See vol. i., p. 255. The Geography of Strabo. Trans, by H. C. Hamilton and W. Falconer, 3 vols., London, 1857. There are several other editions of Strabo's work available in English. Tertullian. See vol. i., p. 195. Apologeticus. Theophrastus. See vol. i., p. 188. Utpivlaroplas, On the History of Plants. Written in 10 books. This is one of the earliest works on botany which have come to us. It was largely used by Pliny. In complete works, Schneider, Leipzig, 1818-1821, 5 vols. On Plants, edited by Wimmer, Breslau, 247 1842-1862. On Plants, edited by Slackhouse, Oxford, 1814. atria, On the Causes of Plants, This was originally in 8 books, of which 6 are now existant. Bibliog. vid. History of Plants. II.--PERIOD COVERED BY VOLUME II. Albategnius, Mohammed bbn Jabir. See vol. ii., p. 15. The original MS. of his principal work, Zidje Sabt, is in the Vatican. A Latin translation was first published by Plato Tiburtinus at Nuremberg, in 1537, under the title De scientia stellarunt. Various reprints of this have been made. Albertus Magnus. See vol. ii., p. 127. Philosophic* Naturalis Isagoge, Vienna, 1514. Alhazen (full name, Abu Ali al-Hasan Ibn Alhasan). See vol. ii., p. 18. Only two of his works have been printed, his Treatise on Twilight and his Thesaurus opticae, these being available in Michael Casiri's Bibliotheca Arabico-Hispana Escuri-alensis, 2 vols., Madrid, 1760-1770. Bacon, Francis. See vol. ii., p. 192. Novum Organum was published in London, 1620. The Letters and Life of Lard Bacon, in 7 vols., by James Spedding, appeared in 1862-1874. Bacon, Roger. See vol. ii., p. 44. Only an approximate estimate of the number of Bacon's works can be given even now, although an infinite amount of time and labor has been spent in collecting them. His great work is the Opus ma jus, "the Encyclopaedia and the Organum of the Thirteenth Century." A partial list of some of his other works is the following: Speculum alchemio, 1541 (trans, into English); De mirabili potestate artis et naturo, 1542 (trans, into English, 1659); Libellus de retardants se-nectutis accidentibus, 1590 (trans, as "The Cure of Old. Age," 1683); and Sanioris medicino Magistri d. Rogeri Baconis Anglici de arte chymio scripta, 1603. 248 Boyle, Robert. See vol. ii., p. 205. Philosophical Works, 3 vols., London, 1738. Copernicus, Nicolaus. See vol. ii., p. 54.