Wondering if the Tubus were in sight, Challis halted the column, ordering the men to be silent, and walked warily forward. When he came up with the guide, the latter pointed to the path about a hundred yards in front. And there Challis saw, not Tubus, but two enormous square-mouthed rhinoceroses, lying in the mud right across the path. At the moment he caught sight of them the great beasts scrambled to their feet, turned their heads in his direction, and snorted. They had evidently scented him. Knowing that the rhinoceros is usually a timid and inoffensive creature, living on herbs, and not a flesh-eater like the lion, Challis expected the beasts to sheer off. But these animals, like other denizens of the wilds, are sometimes driven into hostility and aggression by alarm. There was a moment of suspense. Then the rhinoceroses raised their blunt-horned heads, snorted again, and came at a lumbering charge straight for the head of the column. The guide shouted and threw his spear, which glanced off the tough hide of the first, then he uttered a yell and bolted. Challis had only an instant for making up his mind what to do. On one side of the path was yielding bog, on the other was drier ground, dotted with bushes. The path itself was blocked by the halted column. He dared not use his rifle, for fear of giving warning to the enemy. The leading rhinoceros was charging straight towards him. The only chance of safety was to run. He turned and sprinted across the open ground. The rhinoceros, infuriated by the guide's spear, swerved off the path and followed him. Its companion headed straight along the path. In a few seconds Challis found that the beast, in spite of its size and unwieldiness, was gaining upon him. He darted aside when it was close behind him, expecting that it would continue in its half-blind charge. To his alarm it struck off almost immediately in his direction. There was no friendly tree in sight. The rhinoceros broke through the bushes as if they were cobwebs. Challis dodged, first on one side, then on the other, but the beast showed an alarming nimbleness. More than once Challis escaped its formidable horn only by inches. [Illustration: THE RHINOCEROS IN PURSUIT] Running on in desperation he stumbled, and had given himself up for lost when he was conscious of a diversion. A dark form, running with extraordinary speed, dashed obliquely towards him, and buried a spear deep in the animals' side. It turned savagely to deal with this new assailant, who had darted off at an angle. For a few yards the rhinoceros followed him, then it staggered, made a vain effort to recover itself, and fell a huge heap upon the ground. The negro rushed back, plucked out his spear, and driving it again into the quivering beast dealt it a death-blow. Challis went up to him. Umgabaloo fell on his knees. "I was right," thought Challis, glowing with pleasure. "Any one who says that the negro knows no gratitude lies."