The gamblers remained engrossed in their pastime, as well they could, having thoughtfully arranged the matter with the policeman on duty; gravely they breathed upon the cubes; earnestly they called upon "Little Joe," "Long Liz," "Ada," and the rest; silently they exchanged their stacks of gold pieces as they won or lost. Calvin Gray, but just arrived from Dallas, looked on at the game with some curiosity, not divining its purpose, until McWade pocketed the dice, then mounted a box at the curb and began, loudly: "Now, gentlemen, that is one way of making money, but it is a foolish and a hazardous way. There is a much saner, safer method, and I'm going to tell you about it. Don't pass on until you hear me, for I have a most incredible story to relate, and you'll be sorry you missed it." There was a ripple of appreciative laughter, but the crowd pressed closer as the orator continued: "You've all heard about these 'doodlebugs' who go around locating oil with a divining rod, haven't you? And you don't believe in them. Of course you don't. Neither do I. I can't put any trust in willow twigs, but--we'll all admit that there are forces of nature that we don't understand. Who can explain the principle of magnetic attraction, for instance? What causes the glowing splendor of the Aurora Borealis? What force holds the compass needle to the north? What makes a carpet tack jump onto a magnet like"--the speaker paused and stared hard at a member of his audience who had passed a humorous remark at his expense--"just like I'll jump you, stranger, if you don't keep your trap closed. I say who can read those secrets, who can harness those forces? The man who can has got the world by the tail and a downhill pull. Now then, for the plot of my story, and it will pay you to do a week of listening in the next five minutes. Awhile ago an eminent scientist, unknown to me or to my partner, Mr. Stoner, came into our office, which is at your backs, one flight up, second door to the right, and showed us an electrical device he has been working on for the last eight years. He claimed he had it perfected and that it would indicate the presence of oil on the same principle that one mineral attracts another. 'Oil is a mineral,' said he, 'and I think I've got its magnetic complement. I believe my invention will work.'