It was then nine o'clock in the morning, and the two explorers (for such they might truly be called) followed the river by its left bank. Their way did not offer the smooth and easy surface of an embankment or towing-path, for the river-banks were covered with brushwood, and quite hidden in a bower of every variety of plants; and the festoons of the "cynauchum filiform," mentioned by Burchell, hanging from tree to tree, formed quite a network of verdure in their path; the bushman's knife, however, did not long remain inactive, and he cut down the obstructive branches without mercy. William Emery drank in the fragrant air, here especially impregnated with the camphor-like odour of the countless blooms of the diosma. Happily there were sometimes more open places along the bank devoid of vegetation, where the river flowed quietly, and abounded in fish, and these enabled the hunter and his companion to make better progress westward, so that by eleven o'clock they had gone about four miles. The wind being in the west, the roar of the cataract could not be heard at that distance, but on the other hand, all sounds below the falls were very distinct. William Emery and the hunter, as they stood, could see straight down the river for three or four miles. Chalk cliffs, 200 feet high, overhung and shut in its bed on either side. "Let us stop and rest here," said the astronomer; "I haven't your hunter's legs, Mokoum, and am more used to the starry paths of the heavens than to those on terra firma; so let us have a rest; we can see three or four miles down the river from here, and if the steamer should turn that last bend we are sure to see it." The young astronomer seated himself against a giant euphorbia, forty feet high, and in that position looked down the river, while the hunter, little used to sitting, continued to walk along the bank, and Top roused up clouds of wild birds, to which, however, his master gave no heed. They had been here about half an hour, when William Emery noticed that Mokoum, who was standing about 100 feet below him, gave signs of a closer attention. Was it likely that he had seen the long-expected boat? The astronomer, leaving his mossy couch, started for the spot where the hunter stood, and came up to him in a very few moments. "Do you see any thing, Mokoum?" he asked. "I _see_ nothing, Mr. William," answered the bushman, "but it seems to me that there is an unusual murmur down the river, different to the natural sounds that are so familiar to my ears." And then, telling his companion to be quiet, he lay down with his ear on the ground, and listened attentively. In a few minutes he got up, and shaking his head, said,-- "I was mistaken; the noise I thought I heard was nothing but the breeze among the leaves or the murmur of the water over the stones at the edge; and yet----" The hunter listened again, but again heard nothing.