Ernest nodded. "Nobody's using the horses, so I'll drive in and leave the team at Hackett's. If Dick gets well before I come back he can drive himself out. Otherwise it will be waiting for me. Elsa, do you think you could fix up a clean collar and shirt for me?" "If she can't, I can," offered Charley. "Take anything you can find of mine," Roger's face was more cheerful than it had been for days. "I'll get the reports and drawings ready for you." So, by the united efforts of the two households, Ernest was made ready for a flying trip to civilization. He was so happy and excited over the trip that he really lifted some of the sadness that had hung so heavily over the ranch house. After his departure, Gustav slept at the ranch, in order to do the chores while Roger remained at the Plant. Ever since he had reached the desert Roger had been conducting heat tests and while he was able under perfectly controlled conditions to produce higher temperatures than those of the tables he had used for so many years, his average readings under the absorber glass were less than he had counted on. And so he was at work on a new type, low pressure engine, for which his average temperatures would produce ample heat. Ernest took little stock in his new idea. "It may take fifty years to work it out," he had said the day he left for Washington. "Increase your absorption area and let it go at that. Better men than you have spent their lives on the low pressure idea and failed." "I tell you," Roger had insisted, "that with a few changes of this present engine, I'll produce _the_ low pressure engine of to-day." "Well, go to it, old man! In the meantime, I'll fetch you some money so you can buy all the parts needed, and not have to continue your awful career of mountain brigand. The devilish thing about you inventors is that you putter so. My God, you drive me crazy! I do honestly believe that if it weren't for fear of starvation, you'd be puttering here for ten years." "You're getting to be nothing better than a common scold, Ern," returned Roger with a laugh. "I'll be glad to get you out of the camp. Run along now and do your little errand." With a routine established for caring for the two households, Roger bent all his splendid mind and energies on re-making the engine. Charley, coming to the camp one afternoon, as she or Elsa often did to cheer Roger's long day, watched him as he worked with infinite care to adjust a gauge he had taken apart. "One of the many things that break me up," she said, "is that you missed the visit from the Smithsonian man." "As it turns out," replied Roger, stoutly, "I didn't miss anything. I found when I got to work again that my safety device was inadequate and I've been all this time evolving a new one. If I'd run the engine as it was, I might have had a nasty blow-up and I've made one or two other changes, too, that are important." "The engine doesn't look so very different to me," said Charley.