Increasing their distance from the path, the three marched rapidly through a belt of thin woodland which screened them sufficiently, and came back to the track, after a long round, at a point which Royce calculated to be a good mile ahead of the raiders. They pressed on, avoiding the path, on which Royce's boots would have left tell-tale tracks, but keeping as near to it as was safe. John halted every now and then to look back, and to listen for sounds of the enemy's advance. Royce gave his whole attention to the features of the surrounding country. As they covered mile after mile without finding a spot where anything in the nature of an ambush could be successfully attempted, Royce's hopes sank lower and lower. The country became more and more hilly, and the path followed the undulations in almost a straight line over bare soil. It did not pass through tracts of thick bush or clumps of woodland, which might have afforded opportunities for an ambuscade. Nor were there abrupt corners or overhanging banks that would have lent themselves to the springing of a surprise on the enemy. The Hausas wondered why their master kept on marching so doggedly, now that they were miles ahead. "Eat now, sah?" said John at last. "You can eat as you walk, if you like," replied Royce, "but we won't rest yet." Some little while later, as they were rounding the shoulder of a low hill, John suddenly cried: "Ribber, sah! Savvy ribber here all same." "I can't see it," said Royce. This answer appeared to tickle John, who laughed heartily. "See him bimeby," he said. "Hear him now." And then Royce caught a faint sound like the rustle of leaves in the wind. A few minutes' walking proved that John was right. The track made a sharp bend. On the left of it the ground fell away steeply to a river valley, down which a stream was tumbling rapidly, no doubt to join the Yo somewhere to the east. Royce's drooping spirits took a joyous leap, for the path led down to a frail swinging bridge which spanned the stream. It was made of plant rope, and looked too slight to bear the weight of more than a few men at a time. The possibilities of the situation flashed upon his mind. It was clear that the stream was not fordable at this spot, otherwise there would be no bridge. The African native never puts himself to unnecessary trouble. It was equally clear that the bridge was not strong enough to bear the weight of horses; therefore the mounted men would not cross here, but must go either to the right or to the left to seek a ford. Best of all, on the side of the track remote from the stream, the ground rose so steeply as to form almost a precipice. Here, if anywhere, an attempt to throw the party into confusion might succeed, and the idea of a plan to do even more than that had already suggested itself to Royce.