He hastened back to the bend, and concealed himself by Gambaru's side among the rushes. It was perhaps five minutes later that the first man of the advance guard appeared round the bend. He walked straight down to the bridge-head, followed by five others. Royce watched them eagerly, his heart beating fast. Everything depended on what would happen in the next minute. To his dismay, instead of walking at once on to the bridge, they stood in a group at the end, all talking together. Were they going to wait until the prisoners came down? If they did, it would spoil everything. For half a minute Royce waited in a fever of suspense. Then, to his great joy, the men formed single file again and began to cross the bridge. Now he had a new anxiety--the fear that John would not act quickly enough. But the first of the Tubus was still some yards from the farther bank when there was a slight swishing sound, a tremendous splash, and a babel of yells from the men whom the cutting of the ropes had plunged into the river. Then John, drenched with water, but beaming with delight, came rushing up to join his master, who, with Gambaru, had left his hiding-place and stationed himself at the near side of the bend. As Royce had expected, the shouts of the men had the effect of bringing up the nearest man of the escort at the double, leaving the group of prisoners, of which he was in charge, to follow. The moment he showed himself round the corner Royce dealt him a blow that stretched him on the ground. Gambaru, acting on Royce's instructions, instantly pounced on the man, tore the turban from his head, and calling to John to assist him, stuffed into his mouth a gag made of the linen, and pinioned his arms with strips shred from his loincloth. Royce, meanwhile, stood waiting for the next man, at the same time watching with some anxiety the operations of his Hausas. All, perhaps, depended on their quickness. His anxiety was needless. With ready wit John perceived the nature of his master's design, and within twenty seconds the fallen Tubu was helpless and harmless. [Illustration: COLLAPSE] A few moments later a second Tubu dashed round the bend. Like the first, he had left his gang of prisoners, and run ahead to discover the cause of the outcry, which had now ceased, for the men of the advance guard had been carried far down the rapid stream. The second man was served as the first had been. A third and a fourth appeared, only to meet the same fate. Then there was a pause. Either the remaining members of the escort had not heard their comrades' yells, or the ensuing silence had reassured them.