At the Professor's suggestion, preparations were now made for retiring, and we sought our tent and blankets. In a few brief moments, the others of the party were blowing, in nasal trumpetings, the praises of Morpheus. I could not sleep, however; for each bone had its own individual ache, and was telling how tired it was. Pulling up a tent-pin, I looked out under the canvas. On a log by the fire sat Shamus, his head between his hands, gazing at the coals, and droning a low tune. Occasionally, he would make a dash at some fire-brand, with a stick which he used as a poker, and break it into fragments, or toss it nervously to one side. Whether this was because it resolved itself into a fire-sprite winking at him, or some unhappy memory glowed out of the coals, I tried to tempt sleep by conjecturing. Off at a little distance, I could see one of our men standing guard near the horses, and once or twice my excited fancy thought it detected shadows creeping toward him. A little beyond, nervously stretching his lariat rope, while walking in a circle around the pin, was Mr. Colon's Iron Billy. His clean head erect, and fine nose taking the breeze, the intelligent animal appeared restless, and I could not help thinking that he saw or smelt something unusual, away in the darkness. What if the bottom grass was full of creeping savages? The crescent moon, just rising over the divide, was scarred by many cloud lines, and as yet gave no light. The sensation which had stolen over me was becoming disagreeable, when far off, at some ford down the creek, I heard animals splashing through water, and concluded that Billy's nervousness was caused by crossing buffaloes. The horse had an established reputation as a watch, his former owner having assured us that neither Indian nor wild beast could approach camp without Billy giving the alarm. Presently, Dobeen resumed his droning, which had been suspended for a few moments, this time singing some snatches from an old Irish ballad. The last words were just dying away, when I started to my feet in horror. What an infernal chorus filled the air! Each point of the compass was represented, and we were wrapped around with a discordant, fiendish cordon of sound. Bursting upon us with a deep mocking cry, it ended abruptly in a wild "Ha-ha!" It was such a chorus as pours through Hades, when some poet opens, for an instant, the gate of the damned. Our poor Irishman, at the first sound, had fallen from the log as if shot, but had suddenly sprung to his feet, and was now performing a terror-dance behind the fire with a club. For a moment, I, too, had taken the outburst for the war-whoop of savages, but was saved from a panic by seeing through the gloom the figure of the sentinel still at his post, and the next instant the voice of the guide was lifted, with the re-assuring intelligence--"Only cayotes, gentlemen, only cayotes!"