Page:Africa by Élisée Reclus, Volume 4.djvu/322

254 SOUTH AND EAST Af'EICA. Climate of the Zambese Basin. In such a vast area of drainage as that of the Ku-Bango and Zambese river Bystems, the climate naturally presents many contrasts according to the aspect of the laud, its general relief and distance from the sea. About the region of the farthest sources, comprising a portion of the plateau where the Cuanza and the Kassai also take their rise, the climatic conditions are the same as those of the Angolan uplands. Here the rainfall is abundant, thanks to the moist west winds from the Atlantic ; but the transitions are at times very sudden from heat to cold. So also on the extensive level plains traversed by the Lower Ku-Bango, cool weather alternates with intense heat, although here little moisture is precipitated by the normally dry atmosphere. These regions form, in fact, a northern continuation of the Great Karroo and of tho Kalahari Desert, and almost everywhere present nearly the same meteorological phenomena. Farther east, the Middle Zambese region in the same way reproduces the conditions prevalent in the Transvaal, while the zone of coastlands, being abun- dantly watered and exposed to the regular action of the trade-winds and marine breezes, belongs rather to tropical Africa. The fierce hurricanes so destructive on the high seas, are unknown on this seaboard of the Zambese delta. The most carefully studied part of the whole basin is that of Lake Nyassa, where European missionaries have been stationed for some years. Here the rains, which begin in December and last till April or May, are sufficiently copious, even in a compara- tively dry year, amounting to 90 inches at Bandawe. Towards the south the rainfall gradually diminishes, being scarcely more than 33 inches at Tete, on the Zambese.* Flora. A striking contrast is presented between the wealth of the vegetation on the seaboard and its poverty farther inland. To the rich flora of the coastlands the aspect of equatorial forests is imparted by the great variety of palms, including even a species of the banyan, or as it is here called, the "many-legged tree." But in the interior an exuberant vegetation occurs only in the districts more favoured by a copious rainfall or an abundant supply of running waters. Such are, for instance, the summits of the cliffs exposed to the heavy vapours constantly rolling up from the bottomless chasm of the great Victoria Falls. Speaking generally the Zambese basin, which is entirely comprised within the torrid zone, yields in richness of vegetation to that of the better watered region of the Congo. Its flora is mainly composed of forms common to that botanical zone, but also includes a few species which have penetrated from the Cape northwards beyond the tropic of Capricorn. One of these immigrants is the • Temperature at Bandawe, on the west side of Nyassa, 1 1° 4' S. latitude : mean for November, hottest month, 85' F. ; May, coldest month, 60° ; extreme heat, 99° ; extreme cold, 64°. Mean tempe- rature at Tete, 16' 10' S. latitude, 62° F.: mean for November hottest month, 83'; July, coldest month, 72° F.