Kuka, the capital of Bornu, is near Lake Tsad, but is a small city of inconsiderable importance. Yola, the capital of Adamwa, is larger than Kuka. It was in this province that Dr. Barth discovered the Benue river, a navigable stream and the principal affluent from the east of the Niger. There are many cities in this portion of Africa of far more importance than the capitals of Bornu and Adamwa. Polygamy is universally practiced, and there are probably more slaves than freemen throughout all the vast expanse between the equator and the Desert of Sahara, and Senegambia and Abyssinia. In 1856, Captain Burton, whose “Pilgrimage to El Medinah and Mecca” (which he made in the disguise of a dervish) had just made a sensation in the reading world, explored, with the lamented Speke, a considerable portion of East Africa. The explorations of Grant and Speke in this portion of the continent were also of the greatest value. Thus was a knowledge of the expanse lying between Lake Nyassa, Tanganyika Lake, Victoria Nyanza and the Indian ocean made known to the world. The explorations of Sir Samuel Baker and others in search of the sources of the Nile are familiar to the intelligent public. At this moment there are at least two expeditions engaged in attempting to solve this interesting geographical problem, one, under the patronage of the Prince of Wales, the other under that of the Khedive of Egypt. With this latter is a representative of the same American journal whose Search Expedition under Mr. Stanley discovered the great discoverer on the shores of Tanganyika. [Illustration: AFRICAN BIRD-LIFE.] The most interesting and valuable series of explorations from the west coast of Africa which have been made of late years were those by Paul B. Du Chaillu, an American traveller and student whose work has been freely quoted from in this volume. His explorations embraced some three degrees of latitude and six of longitude near the equator. He penetrated far into the country of the gorilla and the cannibal, and his researches in respect of the people, animals, vegetation, and birds of this part of the continent are confessedly of great value to science.