Roger spread some of the sheets on the table and the black, the yellow and the sandy heads bent over them.
"This," began Roger, "is the general ground plan of a plant designed to produce about 50 horse power. This detail here, which looks like a design for a glassed-in hot bed for early cabbage, is the heat absorber. It consists of a trough lined with some insulating material, covered with two layers of ordinary window glass. Under this window glass I flow crude oil, which absorbs the sun's heat as it comes through the glass. I get some remarkable temperatures, right here in Eagle's Wing. Here is a month's thermometer readings during July."
Austin studied the table thoughtfully. "The heated oil is the fuel for a low pressure engine. What engine do you use?"
"One of my own design. Here are the drawings."
Austin bent over these with absorbed interest and for an hour Roger answered his questions. At the end of this time, Austin lighted his pipe, which had gone out, and took a turn or two up and down the room. Then he paused suddenly in front of Roger and said, "Why don't you go down into Arizona and put up a small pumping plant as an experiment for the Smithsonian? I know this is not the large way, the commercial way, but I am convinced that this is the careful, practical way. Your friend Wolf tells me that the most popular reason given by the business houses you've visited for turning you down has been that you've never actually erected a working plant. Why not try it for us? Then you'll be in a position to talk business."
Roger, his face a still deeper red, looked from Austin to Ernest and back again. He relighted his pipe with fingers that shook.
"How big a plant?" he asked huskily.
"Big enough to irrigate about twenty-five acres of desert for alfalfa. I'm convinced that when you actually undertake to put such a plant in operation, you'll realize that there are details to be remade that you never dreamed of, on paper."
Roger did not speak for a moment. Five years ago he would have refused such an offer as this, without hesitation. It was very different, this, from turning out say a thousand units in six months. Yet, so long had hope been deferred that Roger hesitated, not for lack of enthusiasm for Austin's offer, but because the sudden joy that rose within him made it difficult to speak. Finally he turned to Ernest, who was watching him with a look of inexpressible satisfaction in his beautiful eyes.