Thus, if we consider the known portions of Africa at the time Dr. Livingstone began his first expedition of discovery, and compare them with the known portions of Africa at the time of the finding of Livingstone by the “Herald” expedition, we shall see that nearly all South Africa and much of East Africa has been explored by Livingstone himself; that Baker, Burton, Speke, Grant have added much to our knowledge of the supposed regions of the upper Nile and the “lake country” of East Africa; that Richardson and Barth have informed us of the true nature of the Desert of Sahara, the latter adding a vast fund of information in respect to north-central Africa; that Du Chaillu’s explorations and direct information almost impinge upon the vast area, both upon the east and the south, explored by Dr. Livingstone. The unexplored regions of Africa, therefore, are now small in comparison of the regions explored and in regard to which trustworthy information has been gathered. Whereas, when Dr. Livingstone went to Africa, only the outer portions of the continent had been examined, the regions now unknown are a wide belt eastward of Lake Tsad; a considerable expanse south of Abyssinia; portions of the Desert of Sahara, and of Kalahari; and that expanse in equatorial Africa between the recent explorations of Livingstone among the supposed sources of the Nile and the eastern limit of Du Chaillu’s journeys. It is true that these still unexplored regions embrace the most interesting portion of the continent and extend over an area several times larger than that of France, but in comparison of the portions of this great division of the earth which have now come under the view and the study of civilized man, they are but like a little cloud in a clear sky.