Page:Popular Science Monthly Volume 2.djvu/346

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Dilolo, a small body of water, reached February 20, 1854, is the source of the Leeba. It was only on his return that Livingstone ascertained this. But the courses taken by the different streams he crossed struck him; and the observations he made on his journey back impressing him with the conviction that the Dilolo country was the water-shed of the streams running east and west, led him to confirm the theory of Sir R. Murchison, of which he had not heard at the time, that the form of the interior of the South African Continent is that of an elevated, saucer-shaped plateau. In other words, that the country is gradually depressed toward its centre, sloping from an inner environing mountain-ridge toward which the land rises from the coast. The western ridge was crossed at a spot called Tala Mungongo, lat. 9° 42' 31" S., and, by carefully noticing the course of the various streams flowing thence to the centre, and forming his judgment from what Arab traders had told him—subsequently confirmed by his own observation—that the rivers set inland from a similar ridge on the eastern side of the continent, the conclusion forced itself on Livingstone's mind, that these river systems, uniting at last, pass out to the north and south in two main drains; the northern finding its way to the Atlantic as the Congo on the west coast, and the southern to the Indian Ocean as the Zambési on the east. The configuration of the country alluded to will account for the course of the Leeba from the lake being about S. E., while the Leeambye joins it flowing west from the eastern ridge of the central plateau. But Livingstone also speaks confidently of "a sort of elevated partition in the great longitudinal valley" between the latitudes about 6° and 12° S. It would not be fair to him to suppress the fact that, considering this peculiar configuration of the country, and hearing from some Zanzibar Arabs of the existence of a lake Tanganyenka (Tanganyika) and Nyanja (Nyassa) to the east of Londa where he then was, he was led to the probable conjecture that the region about them would be found to be the water-shed of the Nile to the north, as it was that of the Zambési to the south. Thus his sagacity brought him to anticipate the existence of facts which have since been confirmed by the travels of Burton, Speke, and Grant, and Sir S. Baker; and which only remain to be thoroughly investigated and defined in the completion of those researches the exciting story of whose partial accomplishment we have recently heard.

A few words must dispose of Livingstone's westward journey. Passing various tribes as he wends along, chiefly on oxback, accompanied by his faithful Makololo, he encounters no opposition, but the contrary, till he enters the territory of the Chiboque. There, however, he gets on the track of the Mambari, or half-caste Portuguese slave-traders, from whom the native chiefs exacted heavy tribute, and the hostilities with which he is threatened, on his stanch refusal to submit to their impositions, were avoided simply by his firmness and tact. On his arrival at Loando, May 31, 1854, he was well received by the