I had afterward the satisfaction of seeing the chief, an experienced plainsman, consume a full hour, rifle in hand, working round to the leeward of a dead coyote in the sure and certain hope of bagging a sleeping buffalo. Mirage or no mirage, you must not too implicitly trust your eyes in the fantastic atmosphere of the high plains. I remember that one forenoon I looked forward to the base of the Big Horn Mountains and selected a most engaging nook for the night's camp. My good opinion of it was confirmed when we reached it three days later. The deception in this instance was due to nothing but the marvelous lucidity of the atmosphere and the absence of objects of known dimensions, and these sources of error are sometimes sufficient of themselves to produce the most incredible illusions. When they are in alliance with the mirage the combination's pranks are bewildering. One of the most grotesque and least comfortable of my experiences with the magicians of the air occurred near the forks of the Platte. There had been a tremendous thunder-storm, lasting all night. In the morning my party set forward over the soaken prairie under a cloudless sky intensely blue. I was riding in advance, absorbed in thought, when I was suddenly roused to a sense of material things by exclamations of astonishment and apprehension from the men behind. Looking forward, I beheld a truly terrifying spectacle. Immediately in front, at a distance, apparently, of not more than a quarter-mile, was a long line of the most formidable looking monsters that the imagination ever conceived. They were taller than trees. In them the elements of nature seemed so fantastically and discordantly confused and blended, compounded, too, with architectural and mechanical details, that they partook of the triple character of animals, houses and machines. Legs they had, that an army of elephants could have marched among; bodies that ships might have sailed beneath; heads about which eagles might have delighted to soar, and ears--they were singularly well gifted with ears. But wheels also they were endowed with, and vast sides of blank wall; the wheels as large as the ring of a circus, the walls white and high as cliffs of chalk along an English coast. Among them, on them, beneath, in and a part of them, were figures and fragments of figures of gigantic men. All were inextricably interblended and superposed--a man's head and shoulders blazoned on the side of an animal; a wheel with legs for spokes rolling along the creature's back; a vast section of wall, having no contact with the earth, but (with a tail hanging from its rear, like a note of admiration) moving along the line, obscuring here an anatomical horror and disclosing there a mechanical nightmare. In short, this appalling procession, which was crossing our road with astonishing rapidity, seemed made up of unassigned and unassorted units, out of which some imaginative god might be about to