Occasionally, while riding along in this manner, the three would halt and listen, and then, when certain that they heard nothing, move on again. This was repeated several times, until the two hunters remained motionless longer than usual. When Ned asked the cause of this, Tom replied by asking him whether he heard anything. He answered that he did not. "I hear it," added the scout, as he dismounted and applied his ear to the ground. "What do you make it?" inquired Dick. "Can't tell." Hardynge remained standing beside his steed for several minutes, looking off to the southward, and then he knelt down and bent his ear to the ground again. "It is off yonder," he added, pointing to the southward, and leaping at the same time upon the back of his mustang. Ned listened to catch some explanation; but at this interesting juncture, for some reason only known to themselves, the two men began talking in the Indian tongue. It was interesting to hear their gutteral exclamations, but it would have been much more interesting could he have understood what they were saying, and to know why it was, when talking, that they laughed and looked meaningly toward him. The lad affected not to notice all this, although it piqued his curiosity not a little. A half mile more was ridden at a leisurely gait, when all three drew up their mustangs, and Dick Morris looked meaningly at their young comrade. "Do you hear anything _now_?" Yes, there could be no mistaking it, faint though it was. All three sat motionless and listened. At first, it might have been taken for the far-off rumble of thunder--a fluttering, distant rattle, such as is occasionally heard during the hot summer months. It was not exactly of that character, either, being more like a continuous rattle, coming from some point many miles away. "What do you suppose it is?" asked Tom, of the lad. "I never heard anything like it before. What is it?" "Does it sound like the tramp of animals?" "Not much, it seems to me. It can't be that." "That's just what it is." Ned started. "So it is--so it is. I can notice it now. I hear the sound of horses hoofs on the prairie. The sound is growing more distinct, too, and they must be coming this way, Tom. Is that so?" "That's just what's the matter. We'll see 'em all inside of half an hour, unless we turn tail and run." "Let's do it, then, for there can't be much time to spare." The hunters showed no disposition to flee from the danger approaching, and Ned began to grow alarmed. "Why do you stay here?" he asked. "If your horses are so fleet that no one can catch them, what is the use of letting them do it?" "Don't get scart, my boy," returned Tom Hardynge. "We'll take care of you."