He did not know that while his sense of duty was undergoing no deterioration, the equally strong desire for recreation, for something to make him forget his own trouble without resorting to cowardly or ignoble devices, insisted upon making itself felt. Then the thrilling thought came to him that besides helping Bill he was helping an inventor to do something useful, something that might be the means of accelerating the accumulation of the seventeen thousand dollars he needed. That made the loan strictly business, he thought, with the curious instinct of youth to cover the outside of a beautiful impulse with sordid motives, deeming that a more mature wisdom. He had been sending three dollars a week regularly to his father. He had put it delicately enough. “Please credit me with the inclosed and write it down in the little black book. It's too one-sided as it is; too much Dr. and not enough Cr.” This was all that he had written to his father about his remittances. He had not asked what proportion of the debt was rightfully his. He would not stop to separate the clean dollars from the tainted, but give back the whole seventeen thousand. Nevertheless, he now wished to do something else with his mother's hundred, and the gold coins began to burn a hole in his pocket. One night after supper he said to Bill, “I've been thinking about our experiments.” He paused to let the news sink in. “Oh, you have, have you?” retorted Bill, with the elaborate sarcasm of the elder brother. “Yep. Now if gasoline is going to keep on becoming less and less inflammable, what's the matter with going the whole hog and tackling kerosene?” “Oh, shucks!” said Bill, disgustedly. Then meditatively, “I don't know--” “I do,” said Tommy, decisively. “No scarcity of supply and cheaper.” “Yes, and more power units; go further and cost less. But it will be more difficult--” “Sure thing. That's what you're here for. The first practical kerosene-auto will make a goldmine look like a pile of wet sawdust.” “You're right,” said Bill. “But I've never tried--” “I'll help you,” said Tommy, kindly. “Don't talk about it; think!” This was rank plagiarism from Thompson, and he wouldn't let Bill say another word on the subject. Being compelled to do his thinking in silence made Bill grow quite excited about it. Tommy saw the desire to experiment show itself unmistakably in Bill's face. It made Tommy happy. He was helping some one else. Therefore, he was not thinking of himself. Therefore the secret slept. On the very next morning Tommy went to one of the engineers in the experimental laboratory and asked, “Say, where can I get some literature on kerosene-motors--” The engineer, La Grange, who had early taken a liking to Tommy, threw up his hands, groaned, and cried, “Another!” “Another what?” asked Tommy. “Savior of the industry.” “Is everybody trying--” “Everybody--and then add a couple of millions on top of that. It's worse than Mexico for revolutionists.”