Mileage of Navigable Water.—As a highway into the in terior of the continent the Zambezi, like all other large African rivers, in greater or less degree, suffers on account of the bar at its mouth, the shallowness of its stream, and the rapids and cat aracts which interrupt its course. Nevertheless its importance to commerce is great, as the following recapitulation of its navigable stretches will show: (I) From the sea to the Kebrabasa Rapids, 400 m. (2) From Chikoa, (above Kebrabasa) to within 140 m.
of the Victoria Falls, 700 m. (3) From the rapids above the Victoria Falls to the Katima Molilo Rapids, ioo m. (4) Above the Gonye Falls to the Supuma cataract, 30o m. (5) Above the Supuma cataract, 120 m. Thus for 1,62o m. of its course the Zambezi is navigable for steamers with a draught up to 28 in.
Several of the Zambezi affluents are also navigable for many miles. The Lungwebungu, which enters the upper river, is navi gable for a long distance, thus supplying communication with the extreme north-west corner of the Zambezi basin. Parts at least of the Luena, Kafukwe, Loangwa and the Kwando tributaries are also capable of being navigated. The Shire is also navigable for a considerable distance. The sum of such navigable reaches within the Zambezi basin as exceed ioo m. is nearly 4,00o m.
Exploration of the River.—The Zambezi region was known to the mediaeval geographers as the empire of Monomotapa and the course of the river, as well as the position of Lakes Ngami and Nyasa, were filled in with a rude approximation to accuracy in the earlier maps. These were probably constructed from Arab The first European to visit the upper Zambezi was David Livingstone in his exploration from Bechuanaland between 1851 and 1853. Two or three years later he descended the Zam
bezi to its mouth and in the course of this journey discovered the Victoria Falls. During 1858-60, accompanied by Dr. (after wards Sir) John Kirk, Livingstone ascended the river by the Kongone mouth as far as the Falls, besides tracing the course of its tributary, the Shire and discovering Lake Nyasa. For the next 35 years practically no additions were made to our knowledge of the river system. In 1889 the entrance of vessels from the sea was much facilitated by the discovery by D. J. Rankin of the Chinde channel north of the main mouths of the river. Major A. St. Hill Gibbons and his assistants, during two expeditions, in 1895-96 and 1898-190o, ably continued the work of explora tion begun by Livingstone in the upper basin and central course of the river. Of non-British travellers Major Serpa Pinto exam ined some of the western tributaries of the river and made measurements of the Victoria Falls (1878).