"Well, it's no use to be impatient," he thought. "It's no worse for me than it will be for all the rest. One doesn't like it, but then the pleasure of the travelling and what we shall see right up in the hilly part where the great kopjes rise must make up for a bit of trouble." He moved on again slowly, keeping a sharp look out in the direction of the stream and feeling convinced that he had heard a splash. Then as he listened intently he was just about to come to the conclusion that it was fancy, when there was another, this time a regular heavy, wallowing sound. What it was he could not tell, but he felt sure that it must be some huge beast making its way through the shallow water and mud. Mark's next thought was that the brute, whatever it might be, had left the river and was now stealing slowly towards him. "Can't be a hippo," he thought, "or I should hear him crashing through the reeds and bushes. No, it must be one of those loathsome great efts, the scaly slimy brutes, crawling softly;" and at the very thought of it he pressed thumb and finger upon cock and trigger of his piece twice over so as to prepare for action without the premonitory click that accompanied the setting of each lock. It was hard work to keep from turning sharply and running, but the boy set his teeth and mastered the desire. But he held his piece in front with two fingers on the triggers ready to fire, when all at once from a short distance behind him, and right in the direction in which he would have run, there came a deep, elongated puff as of some big animal, and he felt that his first idea was right, and that one of the huge hippos had caused the wallowing sound in leaving the stream and then made its way right behind him so as to cut him off from his friends. "The doctor might well tell me to load with ball," he said. "Why, a shot gun would not have sent the pellets through the monster's hide." There was a repetition of the heavy breath, apparently much nearer, which set the boy's heart thumping rapidly within his chest, and then the heavy beating began to subside as rapidly as it had commenced, for he said to himself, "Oh, you cowardly fool! Why, I am standing close to the bullocks;" and he stepped boldly out in the direction from which the heavy breathing had come, and began to speak softly to the great sleek animals, a couple of them responding with what sounded like so many sighs. Mark's tramp around the camp became a little faster now as he stepped out and began musing about how easy it was to frighten one's self by imagining all sorts of horrors hidden by the darkness. "Why, the doctor's right," he said; "I don't believe that there's anything one might mind in the little river, and of course, if there were lions near, the ponies and the bullocks would know it before I should. There, who's afraid of its being dark? Not I."