Page:Africa by Élisée Reclus, Volume 3.djvu/530

 436 WEST AFEICA. the upland plains traversed by tlie Lua-jN'gua affluent of the Zambese, and by the Tchassi-Tchambeze main branch of the Upper Congo. These plains, dotted over with clumps of trees, stretch away beyond the horizon without any apparent eminences higher than anthills. Beyond Tanganyika the region of the waterparting between the Congo and the streams flowing to the Indian Ocean is continued northwards by hilly plateaux intersected by irregular ranges, rising to a height of nearly 7,000 feet between Lakes Tanganyika and Rikwah, and even farther north maintaining elevations of 4,000, 5,000 and 5,600 feet in the U-Nyamezi country. Still more lofty are the uplands stretching thence north-eastwards between Lakes Victoria Nyanza and Muta-N'zige, where rises the three-crested Mfumbiro, source of numerous head- waters of the Kagera main branch of the Upper Nile, and still farther north the Kibanga and Gambaragara Mountains seen from a distance by Stanley and others, and by them estimated at over 10,000 feet. In the north-east the divide between the Congo and the White Nile headstreams is faintly indicated b}^ a few undulations of the surface, or isolated hills rising 1,500 or 1,600 feet above the surrounding plains. A like aspect is probably presented by the Congo-Shari waterparting, so that the Central African depression would appear to have been continuous from the dried-up Congo lacustrine basin to the still flooded Tsad depression, which is known to be a mere remnant of a far more extensive inland sea. But whether the two basins are connected or not by intermediate plains, a part of the region is occupied either by isolated heights, such as Mount Mendif, or by less elevated continuous ranges. South of the Welle rises a group of isolated eminences to which the traveller Potagos has given the name of the George Mountains, and the course of the U-Banghi is confined between lofty walls, which seen from the lower reaches present the aspect of the Pyrenees as beheld from the plains of Gascony. Climate. In the Congo basin the mean temperature, lowered on the seaboard by the influence of the cool marine coast stream, is never excessive, seldom rising above 91° F., even in the hottest months, from January to April. What renders the climate trying to Europeans is its great humidity rather than the tropical heats. In the lower Congo regions the glass falls at times as low as 53* F., showing an annual range of nearly forty degrees between the extremes of heat and cold. On the plateaux it is even more considerable, here travellers complaining of temperatures of 98" F. and upwards followed by cool and even chilly nights. Cameron found that water froze during the night on the plateaux about the sources of the Kassai, while Ponel recorded a fiery temperature of 109° F. on the banks of the U-Banghi. The Congo basin lies entirely within the zone of the south-east trade-winds, which prevail in the interior wherever the normal direction is not disturbed by the trend of the mountain ranges. In the south they take a northerly direction,