Page:Africa by Élisée Reclus, Volume 1.djvu/68

 obtained from him a quantity of glass trinkets for the purpose of insuring the stranger's safety by employing them in this way. But since those first visits Lake Albert, already temporarily annexed to the Khedive's possessions, has been navigated in every direction by two steamers, which to pass the Nile cataracts had to be taken to pieces and put together again above the last portages. The transport of the Khedive required no less than 4,800 hands, of which 600 were needed to haul the boiler across the swamps, through the woods, and over the hills. The escarpments along the east coast are far more elevated than those on the opposite side.

It is sometimes asserted that the Nile traverses Lake Albert without mingling with the surrounding waters. But recent inquiry has shown that such is not the case. According to the varying temperatures, the warmer fluvial current spreads in a thin layer over the surface of the lake, gradually blending with it under the influence of the winds. But when the stream is colder it descends to the lower depths of the lacustrine cavity, where it replaces the lighter fluid. Hence, although the inflow is distant scarcely 12 miles from the outflow, the Somerset Nile becomes lost in the great lake, whose superfluous waters must be regarded as the main feeder of the emissary.

This emissary, variously known as the Kir, the Meri, the Bahr-el-Jebel, or "Mountain River," and by other names according to the dialects of the riverain populations, flows normally north and north-east in a tranquil stream winding at a width of from 2,000 to 6,000 feet between its verdant banks. In the middle of the channel the depth varies from 16 to 40 feet, so that throughout the year it is accessible to large vessels for 120 miles below the lake. The shores are fringed with wooded islands and islets, while large masses of tangled vegetation drift with the current, especially at the beginning of the floods. These floating islands consist of a substratum of decomposed foliage and reeds strong enough to support an upper layer of living vegetation, by whose roots and tendrils the whole mass becomes solidly matted together. Daring the course of five or six years the flora becomes renewed, the surface growth decomposing in its turn, and causing the aquatic garden to break up and float away in smaller sections with the stream. But it often happens that the vegetable refuse accumulates in sufficiently large quantities to enable these floating islands to strike root here and there in the bed of the stream, and in the Nile basin whole rivers have sometimes been covered with such buoyant masses, firm enough to bear even the weight of caravans. Owing to the rapid development of this rank vegetation, the Nile has frequently been choked in its upper reaches and compelled to cut new channels in the surrounding alluvia. On the plains stretching west of the present Nile traces are seen in many places of these old beds, or "false rivers," as they are called. The low chain of hills skirting this plain on the west, and forming the water-parting between the Nile and Congo basins, might not inaptly be named the "Explorers' Range." The crests following