The 15th and 16th books contain a description of the second portion of Asia, namely, the southern or the other side of Taurus. In the 15th book, Strabo describes India and Persia, the latter in two chief divisions, viz. Ariana or East Persia, and Persis or West Persia. These countries Strabo never saw; his description, therefore, is founded on the authority of travellers and historians. The topography of India is meagre, and limited to a few towns and rivers; but his account of the people of the country is more copious, he being supplied with materials from the historians of Alexander and of the campaigns of Seleucus in India. He looks on Megasthenes, Onesicritus, Deïmachus, and Cleitarchus as fabulous writers: but his confidence rests chiefly on Patrocles, Aristobulus (one of the companions and historians of Alexander), and Nearchus, the chief commander of Alexander’s fleet. Artemidorus and Nicolaus of Damascus are occasionally consulted. For Ariana or East Persia, he had for his principal authority Eratosthenes; and for Persia Proper, he had, besides the above authors, Herodotus, Xenophon, and Polycletus of Larissa, an historian of Alexander. In the 16th book, he describes the westerly half of south Asia, viz. Assyria with Babylonia, Mesopotamia, Syria, Phœnicia, and Palestine, the Persian and Arabian Gulfs, the coast of Ethiopia, and lastly, Arabia. For the three first countries (the old Assyrian kingdom), his chief authorities are, besides some of Alexander’s historians, Eratosthenes, Poseidonius, and Herodotus; for the remainder he had, in addition to the same writers, Artemidorus, and probably also Nicolaus of Damascus. The account of Moses and the Jews, Heeren surmises, comes from Poseidonius, but it probably proceeds from oral communication had in Egypt; of these countries our author could describe nothing as an eye-witness, except the north-west of Syria. The accounts of Arabia, the Indian and the Red Seas, are from Agatharchides; and much that he describes of Arabia was obtained from his friends, Ælius Gallus and the Stoic, Athenodorus. The 17th book concludes the work with the description of Egypt, Ethiopia, and the north coast of Africa. Strabo had travelled through the whole of Egypt, as far as Syene and Philæ, and writes with the decided tone of an eye-witness. Much verbal information, also, he collected at Alexandria. His most important written authorities are, for the Nile, Eratosthenes (who borrowed from Aristotle), Eudoxus, and Aristo. For the most remarkable events of Egyptian history, he had Polybius, and for later times probably Poseidonius, besides _vivâ voce_ accounts.