18. Unexplored ocean.—This reflects the settled belief of the Greeks that Africa was surrounded by the ocean and could be circumnavigated. Herodotus gives an account, by no means impossible (IV, 42) of a Phoenician expedition, under the Pharaoh Necho, which did so about 600 B. C., returning to Egypt in the third year of their journey. Eratosthenes and Strabo placed the southern ocean immediately below Cape Guardafui; Pliny though it began even at "Mossylum" west of Guardafui; our author shifts it to the Zanzibar Channel, and Ptolemy carried it as far as the Madagascar Channel. The actual southern extension of Africa was not known to Europeans until the Portuguese discoveries in the 15th century. The Saracens seem to have discovered it in the 9th or 10th century, but their knowledge did not reach Europe. The Guinea coast was known in part to the Carthaginians and Romans, and they supposed that it continued due eastward and thus joined the Indian Ocean, or "Erythraean Sea."
The current ideas of geography at this time are reflected by the accompanying map according to Pomponius Mela, about 44 A. D. The contribution of the author of the Periplus was to establish the southern extension of both Africa and India, to a distance never before understood by his civilization.
19. To the left.—This section begins the account of a second voyage, from Berenice to India.
19. White Village (Leukē Komē) is placed by most commentators at El Haura, 25° 7′ N. 37° 13′ E., which lies in a bay protected by Hasani Island. The name Haura also means "white," and the Arab name itself appears as Auara in Ptolemy. The place is on the regular caravan route that led, and still leads, from Aden to the Mediterranean.
The words "from Mussel Harbor," in the text, are probably there only through an error from copying. The distance and direction are more nearly right from Berenice, which is the starting-point named at the beginning of this paragraph.
19. Petra. (30° 19′ N., 35° 31′ E.) lay on the Wady Musa, east of the Wady-el-Araba, the great valley connecting the Dead Sea with the Gulf of Akaba. It was the great trading center of the northern Arabs, and the junction of numerous important caravan-routes, running from Yemen northward, and from the Persian Gulf eastward. Thus it controlled the Eastern trade from both directions, and held its advantage until the results of Trajan's conquests transferred the overland trade to Palmyra; the sea-trade having been already diverted to Alexandria.
