On the old maps the Nyassa and the more northern lakes, Victoria Nyanza and Tanganyika, are given with a good deal of accuracy.
We must believe, then, that those who compiled these early maps must have had some definite knowledge of these regions.
It is believed that they gained this knowledge from the Arabs. Various settlements were located along the eastern and southeastern coast of Africa, extending from the Red Sea to Sofala.
Strange to say, although the lower region of the Zambesi, for a distance of three hundred miles at least, has been in the hands of the Portuguese since the early part of the sixteenth century, yet it is only since the middle of the present century that we have succeeded in getting any accurate or scientific knowledge of the vast territory.
This knowledge we owe to the untiring exertion of such intrepid African explorers as Dr. Kirk, Charles Andersson, Dr. Livingstone, and others.
Upon Dr. Livingstone's map the total length of the main stream, from the mouth to the point in the course where the Leeba River joins it, cannot be less than twelve hundred miles.
The Leeba River proceeds from Lake Dilolo, which is situated on the summit of the watershed which divides the rivers that run northwest into the Atlantic from those which run southeast into the Indian Ocean.
A curious fact is connected with Lake Dilolo; it appears to have two outlets, one to the north and one to the south. The northern outlet probably joins the system of lakes west of Tanganyika.
The river basin of the Zambesi has many features of interest. On the north it probably terminates with a portion of the river system of the Nile. On the west it is separated from the Orange River basin and the various rivers running through Ovampo Land into the Atlantic by a rather undefined watershed, which crosses the Kalahari Desert. On the northwest the main waters very likely have their rise in the near vicinity of the tributaries of the great Congo River.
A well-defined mountain range on the southeast separates the rivers which flow into the Zambesi from those which unite to form the Limpopo.