The shooting he had heard some time previous to his appearance at the base of the big sand dune had not been done by Indians. He was almost convinced of that now. Or, if Indians had done the shooting, they had not yet observed him. The fact that he had seen no smoke signals proved that. Still, there was the deep silence on every hand to bring doubt into his mind; and he knew that Indians--especially Apaches--were tricky, sometimes foregoing the smoke signals to lie in ambush. And very likely--if they had seen him coming--they were doing that very thing: waiting for him to ride into the trap they had prepared. He had not been able to locate the point from which the reports had come. It had seemed to him that they had come from a point directly westward; but he could not be sure, for he had seen no smoke. He talked no more to the horse, sitting rigidly in the saddle, erect, his head bent a little forward, his chin thrusting, his lips curving with a bitterly savage snarl. He felt the presence of living things with him in the desert; a presentiment had gripped him--a conviction that living men were close and hostile. Reaching downward, he drew the rifle from the saddle holster and examined its mechanism. Placing it across his knee, he drew out his heavy pistols, one after another, slowly twirling the cylinders. He replaced the pistols, making sure that the holster flaps were out of the way so that they would not catch or drag at the weapons when he wanted to use them--and with the rifle resting across his legs near the saddle horn, he rode slowly forward. He swung wide of even the small sand dunes as he passed them, and he kept a vigilant eye upon the dead rocks that dotted the level at infrequent intervals. Even the cactus clumps received flattering attention; and the little stretches of greasewood that came within range of his vision were examined closely. At the end of half an hour he had seen nothing unusual. Here and there he had noticed a rattler lurking in the shade of a rock or partly concealed under the thorny blade of a sprawling cactus; and he had seen a sage hen nestling in the hot sand. But these were fixtures--as was also the Mexican eagle that winged its slow way in mile-wide circles in the glaring, heat-pulsing sky. The rider again halted the black horse. The presentiment of evil had grown upon him, and he twisted around in the saddle, sweeping the desolate vast level with cold, alert, puzzled eyes.