"'Sensible idea,' says I. 'But when we are out, suppose you and I have a talk on that subject.' "She looked at the toe of her shoe for a minute again, turned red and white around the gills, looked up at me, shyly at first, then fully and fairly, stretched out her hand and said: "'Yes; if you care to.' "Course, I didn't _care_, or nothing--no more than a man cares for his head. "I guess that was about a half engagement, anyhow, it's the only one we ever had. She said it would be ruinous to our plans if I was seen with her then or afterward; and agreed to leave a note at the house for me by next trip, telling me her plan--which she should talk over with her father. "A couple of days later I got in from a round trip and made a dive for the boarding-house. "'Any mail for me, mother?' I asked old Mrs. Cameron. "'No, young man; I'm sorry to say there ain't'. "'I was anxious to hear from home.' "'Too bad; but maybe it 'll come to-morrow.' "I was up to fever heat, but could do nothing but wait. I went to bed late, and, raising up my pillow to put my watch under it, I found a note; it read: "'Midnight, July 17. "'DEAR JOE: "'Just thought of that rule for changing counter-balance you wanted. There has always been a miscalculation about the weight of counter-balance; they are universally _too heavy_. The weights are in pieces; take out two _pieces_; this treatment would even improve a mule sweep. When once out, pieces should be changed or placed where careless or malicious persons cannot get hold of them and replace them. All is well; hope you are the same; will see you some time soon. "'JACK.' "Here was apparently a fool letter from one young railroader to another, but I knew well enough that it was from Rachel and meant something. "I noticed that it was dated the _next night_; then I commenced to see, and in a few minutes my instructions were plain. The old five-stamp mill was driven by a mule, who wandered aimlessly around a never-ending circle at the end of a long, wooden sweep; this pole extended past the post of the mill a few feet, and had on the short end a box of stones as a counter-weight. I would find two packages of gold there at midnight of July 17. "I was running one of those old Pittsburgh hogs then, and she had to have her throttle ground the next day, but it was more than likely that she would be ready to go out at 8:30 on her turn; but I arranged to have it happen that the stand-pipe yoke should be broken in putting it up, so that another engine would have to be fired up, and I would lay in.