The days passed quietly for the two watchers after Johnny had gone back to the Question-Mark, the hours dragging in monotonous succession. In the Sand Creek camp time passed pleasantly enough, but out on the great, upslanting billow of sand north of Sweet Spring, devoid of shelter from the blazing sun and from the reflected glare of the gray-white desert around it, was another matter. Prone on his stomach lay Hopalong on the northward slope, his face barely level with the crest of the ridge. Down in the hollow behind him was his horse, picketed and hobbled as well, and at his side on his blanket to keep the cutting sand and clogging dust from barrels and actions lay his rifle and his six-guns, so hot that their metal parts could not be touched without a grimace of discomfort coming to his face. The telescope at intervals swung around the shimmering horizon, magnifying the dancing heat waves until the distortion of their wavering, streaming currents at times rendered the view chaotic and baffling. Strange sights were to be seen in the air and knowing what they were he watched them as his only source of amusement. A tree-bordered lake appeared, its waters sparkling, arose into the air, became vague and slowly dissolved from view, calling from him caustic comment. Inverted mountains reached down from the heavens, standing on snow-covered tops, writhed more and more from their outer edges and melted down from the up-flung bases, slowly fading from view. They were followed by a silvery, winding river, certain features which caused him to think that he recognized it and while he studied it a herd of cattle upside down, and greatly magnified, pushed through into sight as the river scene faded away. Another hour passed and then a steep-walled, green valley inverted itself before his gaze. He could make out a hut and a few trees and then as mounted men began to ride up its slanting bluff trail his attention became riveted on it and he reached for the hot telescope. One look through the instrument made him grunt with disgust, for the figures danced and shrunk and expanded, weaved and became like shadows, through which he looked as though through a rare, discolored vapor. He was mildly excited and tried in vain to search his visual image of the sight for the faces of the men; but it was in vain, and he opened his eyes as the image faded and then closed them again to better search the memory picture. This, too, availed him nothing and he realized that he had not really seen the faces. He was perplexed and vexed, for there was something familiar about some of those riders. About to move for a look around through the telescope, he yielded to a humorous warning and lay quiet for awhile. Was it possible that the mirage had been double-acting, and had revealed each to the other?