In B.C. 276 was born at Cyrene, in North Africa, Eratosthenes, a Greek geographer, who was made Librarian at Alexandria. From the information he collected and collated (supplied, no doubt, by Greek traders) he, first of all known geographers, sketched out with fair accuracy the course of the Nile and its two great Abyssinian affluents as far south as the modern Khartum. He hinted at the lake sources and first mentioned the Nubians. It was the conquest of Egypt from Persian domination by Alexander the Great which really did more to extend Greek commerce and civilisation and the use of the Greek language over eastern Africa and western Asia than has even been done at a far later date in other parts of the world for German commerce, knowledge, and the German language by the unification of Germany under Bismarck, William I., and William II. Greek explorers visited the Nile as far south as the junction of the Astapus (Blue Nile), and Greek settlements were made on the island of Sokotra, and possibly at other points near the mouth of the Red Sea. Greek traders even visited the East African coast as far as Pangani, opposite Zanzibar. The Greeks revealed India to Europe, and the commerce which sprung up there through Greek agencies on the Persian Gulf and the Red Sea gave unwilling navigators, in those days before steam force, some acquaintance with the eastern coast of Africa as far south as Zanzibar. Yet the Greeks in all these regions were (as subsequently happened with the Portuguese) but the followers of the Arabs and Phœnicians. Some impulse, kindred in origin, no doubt, to the evolution of the Phœnicians, had created an ancient civilisation in southern and western Arabia which perhaps reached its climax in the lofty, well-watered, and fertile country of Yaman. Much of southern Arabia, however, several thousand years ago, was less arid than at the present day. The rainfall was greater, and the already civilised inhabitants industriously preserved the precious water by dams for purposes of irrigation. This civilisation may be briefly styled Himyaritic or Sabæan,--perhaps the last name is the more comprehensive. These Sabæan Arabs of south and southwest Arabia, separately or in conjunction with their Phœnician cousins, pursued their search for metals down the east coast of Africa, along which they made settlements which are probably the sites of most of the modern emporiums of commerce on the same coast. They had reached the mouth of the Zambezi and ascended that river, and had penetrated as far south as, let us say, Delagoa Bay. It was perhaps their exploration of the Zambezi which led them to discover alluvial gold in the vicinity of that river, though they afterwards found a shorter route to the gold fields by way of Sofala. In this way they forestalled by some twenty-five hundred years modern Rhodesian enterprise, and gold was worked in the regions to the south of the Lower Zambezi and