The banks of the river were at this time appearing to greater advantage than before. Many trees were putting on their fresh green leaves, though they had got no rain, their lighter green contrasting beautifully with the dark motsouri, or moyela, now covered with pink plums as large as cherries. The rapids, having comparatively little water in them, rendered our passage difficult. The canoes must never be allowed to come broadside on to the stream, for, being flat-bottomed, they would, in that case, be at once capsized, and every thing in them be lost. The men work admirably, and are always in good humor; they leap into the water without the least hesitation, to save the canoe from being caught by eddies or dashed against the rocks. Many parts were now quite shallow, and it required great address and power in balancing themselves to keep the vessel free from rocks, which lay just beneath the surface. We might have got deeper water in the middle, but the boatmen always keep near the banks, on account of danger from the hippopotami. But, though we might have had deeper water farther out, I believe that no part of the rapids is very deep. The river is spread out more than a mile, and the water flows rapidly over the rocky bottom. The portions only three hundred yards wide are very deep, and contain large volumes of flowing water in narrow compass, which, when spread over the much larger surface at the rapids, must be shallow. Still, remembering that this was the end of the dry season, when such rivers as the Orange do not even contain a fifth part of the water of the Chobe, the difference between the rivers of the north and south must be sufficiently obvious. The rapids are caused by rocks of dark brown trap, or of hardened sandstone, stretching across the stream. In some places they form miles of flat rocky bottom, with islets covered with trees. At the cataracts noted in the map, the fall is from four to six feet, and, in guiding up the canoe, the stem goes under the water, and takes in a quantity before it can attain the higher level. We lost many of our biscuits in the ascent through this. These rocks are covered with a small, hard aquatic plant, which, when the surface is exposed, becomes dry and crisp, crackling under the foot as if it contained much stony matter in its tissue. It probably assists in disintegrating the rocks; for, in parts so high as not to be much exposed to the action of the water or the influence of the plant, the rocks are covered with a thin black glaze.