They had camped one noon hour at a Desert pool beneath a cottonwood, where the putrid carcass of a dead ox polluted air and water. The Ranger whittled the cottonwood branches for a small chip fire, and he boiled enough water to fill the skin bag for the next day's travel; but a high wind was blowing, restless, nagging, gusty, pelting ash dust in their eyes, and not to lose the trail, they had pressed on through the sweltering heat of mid-day. Wayland's muscles had begun to feel hardened to the dryness of knotted whip cords. His skin had bronzed swarthy as an Indian's. He was beginning to rejoice in the vast spacious relentless Desert with its fierce struggle of life against death; the cactus, the greasewood, the brittle sage brush, all matching themselves against the heat-death. Was there a thing, beast or bush, not armed with the fangs of protection and onslaught? Wayland looked at his leather coat. It had been jagged to tatters by thorn and spine. Silent, too; the struggle was silent and insidious and crafty as death. Who could guess where the water-pools lay beneath the dry gravel beds; or why the cactus fortified its storage of moisture in bristling spear points; the greasewood and pinon with thorns and resin; the sage brush with a dull gray varnish that imprisoned evaporation? The very crust above the earth of ash and silt conspired to hide the trail of wolf and cougar; and wolf and cougar, wren and condor, masked in colors that hid their presence. Twice Wayland had almost stumbled on a wolf sitting motionless, gray as the ash, watching the horsemen pass; pass where? Was it down the Long Trail where the tracks all point one way? Yet the fierceness, the craft, the relentless cruelty of the silent struggle matched his own mood. He felt the stimulus of the high dry sun-fused tireless air. He began to understand why the Desert prophets of the East, who camped on sand plains rimmed round and round by an unbroken sky line, had been the first of the human race to grasp the idea of the Oneness of God. And was it not the Desert prophets, who had preached a God relentless as he was merciful; and the retribution that was fire? Well, Wayland ruminated, who should say that they were wrong? If the God who created the Desert, was the God of life; but there, his thought had been broken by coming on the withered carcass beside the yellow pool. "They can't keep going on in this heat! We'll run 'em down if we can only keep going," Wayland had said; as they set out again in the blistering wind; but to his dying day, he will never forget the traverse of the Desert in that mid-day sun. To his dying day he will never see the spectrum colors of white light split by a prism, or the spectrum colors of a child's soap bubble, without living over the tortures of that afternoon, for the air, whipped to dust by the hurricane wind, acted as a prism splitting the white flame of light to lurid reds and oranges and yellows and violets.