The boy was in terror lest the brute should strike the piece and knock it down, in which case it was likely to be discharged and to be placed altogether beyond his reach. But the dreaded creature sat as motionless as if he were a carved statue in front of some gentleman's residence, his eyes fixed upon his supper, which had escaped him by such a narrow chance. The situation was about as interesting as it could well be, and, in fact, it was rather too interesting for Fred, who was alarmed at the prospect of being besieged by a mountain wolf. After the lapse of a minute or two, the brute quietly rose from his haunches, trotted a few paces, and then gave utterance to the dismal wail peculiar to his species. It had a baying, howling tone, which made the chills creep over the boy from head to foot. He had heard the barking and howling of wolves when crossing the prairies, but there was deep, thunderous bass to the one which now struck upon his ear such as he had never before heard, and which gave it a significance that was like a voice from the tomb. The instant the brute left his station, Fred reached down, seized the muzzle of his gun, and drew it up. Then he made his way some twenty feet above, where he could feel secure against any daring leap from his foe. He had scarcely perched himself in this position, when the bay of the wolf was answered from fully a dozen different directions. He had called to his comrades, and their replies came from every point of the compass--the same rumbling, hoarse, wailing howls that had notified them where a prize awaited them. A minute later, the brute trotted back to his place, where he sat down until the arrival of reinforcements. “It isn't one wolf, but a hundred, that going to besiege me!” gasped the terrified boy. He spoke the truth. CHAPTER XXI. A TERRIBLE NIGHT The prospect of being besieged all night in a tree by a pack of mountain wolves was not a pleasant one by any means, and Fred, who had climbed up among the branches with the object of securing a few hours' slumber, found little chance of closing his eyes for even a minute. “It might have been worse,” he reflected, as he listened to the dismal howling, “for if they had happened to come down upon me when I was walking along the ravine, I could n't have gotten into any place like this in time to save me. Wolves don't know how to climb trees, and so long as I stay here I'm all right; but I can't stay here forever.” By-and-by there was a sharp pattering upon the ground, and then the hoarse howling changed to quick, dog-like yelps, such as these animals emit when leaping down upon their prey, and which may be supposed to mean exultation.