description is given by Prof. J. M. Gregory (The Great Rift Valley, London, 1896). It is a natural depression beginning at the lower shore of the Red Sea between Massowa and the straits, taking a south-westerly direction through Abyssinia to the British and German East African possessions, including lakes Rudolf, Nyanza, Tanganyika and Nyassa, and running almost to the Zambezi. While it is unlikely that this valley was ever at one time under the control of any Arabian power, it is probable that the tribes inhabiting it were in more or less regular commercial relations with the North, and that it was a more important avenue of trade than the sea-coast with its broad unhealthy swamps. It is indeed quite possible that the Mashonaland gold, which lay at no great distance south of the valley, might to some extent have found its way along this natural trade-route by exchange from tribe to tribe; and it is entirely unnecessary, in disproving the antiquity of the Mahonaland ruins, to attempt to disprove the manifest fact of early Arab influence and infusion along the East African coast. Neither is it necessary to deny the general infiltration of early Arabian culture in two directions from the head-waters of the Nile, southward down the rift-valley, and westward through the Sudan toward the Gulf of Guinea. In fact this general spread of culture, folk-lore and religious beliefs and practices, is too well attested to admit of denial.
17. Palm oil.—The word in the text, nauplios, is corrected to nargilios, a word which appears in modified forms in other Greek geographers. This is the Sanscrit narikela, narikera, Prakrit nargil, "cocoanut," and the appearance of the word on the Zanzibar coast is of course a confirmation of Indian trade there. (See Lassen, op. cit., I, 267.) The Greek word was koix, whence the adjective koukiophoros, Latin cucifera, from which the Periplus, § 19, coins the Greek adjective koukinos.
This palm oil was from Cocos nucifera, Linn., order Palmeae; probably native in the Indian archipelago, and carried by natural causes as well as Hindu activity to most of the tropical world. It is one of the most useful plants known, providing timber for houses and ships, leaves for thatch and fiber for binding and weaving, aside from the food value of the nut, fresh and dried, and the oil. As a medicine also it was of importance to the Hindus, the pulp of the ripe fruit being mixed with clarified butter, coriander, cumin, cardamoms, etc., to form their narikela-khanda, a specific for dyspepsia and consumption. The nut was described by Cosmas Indicopleustes in the 6th century as argellion: and by Marco Polo in the 13th century (I, 102; II, 236, 248) as Indian nut. (See also Watt, op. cit., 349–363.)
