The moon was now well up in the sky, and the members of the party were enabled to discern objects at a greater distance than at any time since starting. When Tom Hardynge announced that they had passed through this spur of mountains, the three instinctively turned their eyes to the westward, where the prairie stretched away until it vanished in the gloom.

"There's a clean hundred miles or more of level plain," added the hunter. "I've traveled it many a time and I ought to know."

"You're right," said Dick. "That's a good sweep of prairie, and we ought to make good time over it, for our horses have had a long rest."

"There's only one thing that troubles me," ventured Ned Chadmund, when the heads of all their animals were turned westward; "I'm so hungry and faint that I can hardly sit on my horse."

"That's bad," said Tom, feelingly. "I never thought of that when we had a good chance among the mountains to fetch down some game. We ain't apt to run agin anythin' in the hash line while riding along on the prairie; but we'll try it, and if we don't we'll turn off to a little spot where I know we shall hit it."

Ned expressed his willingness to do this, and the company started. Instead of going in Indian file, as they had done while among the mountains, they rode side by side at an easy swinging gallop, the prairie lightening up as they advanced, and the surface continuing of the same impact character, which rendered it the most favorable possible for horseback riding. To one who, like the boy, had tramped and trudged along until scarcely able to stand, this change was of the most pleasing character. He felt comfortable and anxious to ride ahead for hours, the only drawback being that gnawing hunger, that weary faintness, which could only be dissipated by food.

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."

He much preferred that they should all take care of themselves by giving their animals the rein and permitting the Apaches to make no nearer approach. But the scouts were obstinate and remained as motionless as statues. The tramping of myriad feet came nearer and nearer, until the sound partook of one general, thunderous undertone of the most trying character to the lad. It seemed to him so much like suicide—this waiting for a terrible danger as it steadily approached—that he was strongly tempted to start his horse away on his own account.

"Look!" called out Morris, pointing toward the southwest.

Following the direction indicated, the lad saw what appeared to be a heavy cloud lying low down in the horizon, but creeping slowly upward, like the sulphurous vapor that sometimes hovers over a battle field.

"What is it?" he asked, terrified, knowing that it was not the presage of a storm such as sometimes sweeps over the prairies.

There was something strange and unnatural in its appearance, accompanied, as it was, by the tremulous, thunderous rumbling. By and by, as this uproar came nearer and nearer, a still more curious sight presented itself. The prairie seemed agitated, trembling and quivering with a peculiar, wave-like motion, such as the ocean shows when it is subsiding after a severe storm. There was a sea, a living sea, spreading tumultuously over the plain. Dark, heaving masses were constantly verging nearer, as they moved rapidly toward the northeast. Suddenly light broke in upon the mind of Ned Chadmund.

"I know what it is!" he exclaimed. "They are buffaloes."

"Correct," assented Tom, with a laugh. "They are passing pretty close, but we're out of their way."

The buffaloes surged so near to where the three horsemen stood that more than once Ned started with a fear that they would be overwhelmed; but the hunters showed such calmness and self-possession that he was reassured. All at once a furious trampling was heard, and two of the animals that had become separated from the others in some way, dashed directly by the horsemen and out upon the prairie.

"Now, Ned," called out Tom; "there's your chance! Take that head one! He will make you a good supper if you can fetch him down!"

The lad and his animal were seized with a sudden inspiration seemingly at the same time. Just as the heart of the young hunter swelled with a wild desire to bring down the noble game, the mustang bounded away in pursuit of the very buffalo which had been indicated by the trapper. As the rider saw himself drawing rapidly near the huge body, lumbering awkwardly but rapidly along, he was seized with a fluttering which, perhaps was natural, but which, unless overcome, was fatal to any hopes of procuring any supper. The mustang drew steadily nearer, Ned's agitation increasing every minute, until pursuer and pursued were running side by side.

This was the critical moment when the rider should have fired, and when the horse had been taught to expect him to do so; but when our hero raised the heavy Indian gun to his shoulder, his trembling, together with the jolting of his mustang, now upon a dead run, told him that it would be useless to fire, when the only chance of hitting his prey was by the merest accident. Accordingly, he lowered his gun, in the hopes of quieting his nerves, so as to bring himself up to the self-appointed task. As he did so, his horse began shying off from the buffalo. He was afraid of the horns of the enraged creature, and having given him all the opportunity he could expect, he was not willing to keep him company any longer. The paths continued to diverge until they were twenty yards apart, when the mustang appeared to think all danger was passed. By this time Ned Chadmund felt that he was master of himself, and he turned the head of his horse toward the immense fugitive, still gliding forward at the same terrific rate.

"I'll fetch him this time," he muttered, with a determined air.