The Congo has a length of more than three thousand miles. The maritime region of the Congo River basin is restricted in its character. For a few miles inward the ground has an upward slope; then the traveler is confronted by ridge upon ridge of hills, which gradually assume the character of high mountains.
The Congo rushes on through this mountainous section, as though through one of our western cañons, till it reaches Stanley Pool. Here the channel becomes much broader, the stream attaining a width of five miles, with an extraordinary depth of water. As the river spreads itself to attain this breadth, it flows placidly on through fertile plains, rich in vegetation.
Geographers have, for convenience, divided the river into well-defined sections, the Upper and the Lower Congo.
The Lower Congo has a length of about three hundred and thirty miles. It is the part of the river between Leopoldville—situated on the banks of Stanley Pool—and the sea and has a navigable current for about one hundred miles, between Vivi and the sea. Above Vivi the river for about fifty miles is lined on either side by high slate cliffs. These tend, of course, to narrow the channel. It is in this section that the Lower Livingstone Falls occur, and prevent navigation.
For a distance of about ninety miles above these falls the course of the river is somewhat broken, but it becomes navigable as far as Manyanka. Here the Upper Livingstone Falls are situated, and the river again becomes unnavigable.
The Upper Congo starts at Stanley Pool, and as far as Stanley Falls—a distance of over one thousand miles—has a navigable current. It is, in fact, the grand highway for commerce right into the heart of Africa.
From Stanley Falls to Nyangwé, a distance of nearly four hundred miles, the river has a more or less broken current.
Between Nyangwé and Lake Moero there is still another stretch of four hundred miles.
More than two hundred miles from Lake Moero lies Lake Bangweolo, or Bemba. At a distance of nearly four hundred miles from Bemba the Congo, under the name of the Chambesi, takes its rise.
During Dr. Livingstone's explorations to discover the sources of the Nile and to penetrate the secrets of the lake region of Africa, he became much interested in the course of the Chambesi, which he thought, at first, might be one section of the Zambesi. The names seemed to him somewhat similar in sound, and he decided to make an exploration of the stream.