I have said that Nature has supplied each side of Africa with one great river. By going some hundreds of miles southward along the coast from Zanzibar the traveller reaches the mouth of the Zambesi. Livingstone sailed up this river once, and about a hundred miles from its mouth discovered another river twisting away northwards among the mountains. The great explorer was not the man to lose such a chance of penetrating the interior. He followed this river up, and after many wanderings found himself on the shores of a mighty lake. The river is named the Shiré, and the lake--the existence of which was quite unknown before, is Lake Nyassa. Lake Nyassa is 350 miles long; so that, with the Zambesi, the Shiré, and this great lake, we have the one thing required to open up East Central Africa--a water-route to the interior. But this is not all. Two hundred and fifty miles from the end of Lake Nyassa another lake of still nobler proportions takes up the thread of communication. Lake Tanganyika is 450 miles in length. Between the lakes stands a lofty plateau, cool, healthy, accessible, and without any physical barrier to interrupt the explorer's march. By this route the Victoria Nyanza and the Albert Nyanza may be approached with less fatigue, less risk, and not less speed, than by the overland trail from Zanzibar. At one point also, along this line, one is within a short march of that other great route which must ever be regarded as the trunk-line of the African continent. The watershed of the _Congo_ lies on this Nyassa-Tanganyika plateau. This is the stupendous natural highway on which so much of the future of East Central Africa must yet depend.