With the first streak of dawn he was up and on. Going was slow, for now the real torture of desert thirst was on him and he knew that unless he found water that day, buzzards would be circling over him on the morrow. By ten o'clock his tongue was swelling and he seemed to have ceased to sweat, and Peter leaned panting against the rocks in the shade of which Roger paused to rest. After a half hour, Roger rose to his feet. The morning had been breathless but as he rose, a little hot gust of air blew up from the canyon below. Instantly Peter raised his head and sniffed. The gust increased to a breeze. With ears lapped forward the burro tottered to the canyon edge and began feebly to pick his way downward. Roger watched him for a moment. Then, "I don't know what you've discovered, old man," he said thickly, "but what's good enough for you, is good enough for me," and he followed weakly after him. There was considerable rolling and scrambling done by both Peter and Roger before they reached bottom. When Roger finally scrambled panting to his feet, face burning, ears ringing, he found that they were in a narrow valley thick grown with scrub oak. Peter had rolled the last ten feet, and when he brought up against a barrel cactus, he could not rise until Roger had pottered over and pulled weakly on his bridle. Then he walked shakily across the canyon, Roger close behind him. A little pool reflecting the sky and the fern-like leaves of the mesquite that bordered it lay at the base of the great brown rock. Roger, as he drank, had vague recollections of warnings he had read about the dangers of over-drinking after water famine. But he was developing an implicit faith in Peter's wisdom and Peter was drinking till his thin ribs swelled. When he had entirely slaked his thirst, Roger rested for a bit, then looked about him. A trail led along the canyon from the spring, westward. Roger filled the canteen, then he and Peter took the trail. It led perhaps a quarter of a mile to a deserted mine, a mine of vast workings and huge ramshackle sheds that were innocent of either windows or doors. The engine house had been nailed up, but Roger's strength and spirits had been much revived by the water. He rested for awhile, then wrenched off some boards and went in, Peter struggling to follow, then giving the idea up and standing at rest in the shade. A complete ore separator plant was installed within. At the fore end of the shed was a gas producer engine in perfect condition as far as Roger could tell, except for the sand that had sifted over it. It was of a type with which he was not familiar and he spent a half hour in thoughtfully examining it, and making notes on a scrap of paper concerning it. He was absorbed in a new idea when he closed up the shed and whistled to Peter who had found some old alfalfa hay in a manger under a shed and was just finishing it off.