"I guess they're geologists getting specimens," ventured Roger. "Maybe," admitted Adrian, who was beginning to lose interest in the men since they seemed to be doing nothing out of the ordinary. The boys followed along in silence, taking care to keep from observation. Suddenly the two men stopped. The older one set his valise down and took something from it. This he seemed to be fitting together, and when he had finished he had a long, slender steel rod, which Mr. Ranquist, after carefully selecting a place on the surface, shoved into the soil. He twisted it about and then drew it up, after which he and Mr. Dudley carefully examined the end that had gone down into the earth. "I have it!" exclaimed Roger. "They're prospecting for oil, that's what they are. They're not railroad surveyors at all." "Perhaps they're after gold," suggested Adrian, all excited at the very thought. "Cracky! If there should be gold in Cardiff, wouldn't it be great? If there was only a little on dad's land, he wouldn't have to worry about that mortgage." Adrian had started forward, forgetting the caution he previously used to prevent the men from observing him, and as he did so he dislodged a big stone, which crashed down the hillside with a clatter and bang. At the sound both men looked up suddenly and saw the startled and surprised boys. Mr. Dudley made a quick motion of closing the valise and seemed about to hurry on. But with a hasty gesture Mr. Ranquist detained him and spoke a few hurried words to his companion. Then, turning, the young engineer came slowly toward the boys, who did not know whether to go or stay. "Live around here?" asked Mr. Ranquist, as he drew near Roger and Adrian. "'Bout two miles--over to Cardiff," answered Adrian. "Oh, yes. Um. Nice day, isn't it? Are you hunting?" the man asked, suddenly. "Nope," from Adrian. "Fishing?" "Nope." "What, then?" "Prospecting." "Prospecting?" "Yep." "What after?" "Old bones." "Old bones? Are you joking, my lad?" "No, sir, not a bit. We're looking for old bones. They'll bring half a cent a pound, you know," and there was not the trace of a smile on Adrian's face. "Oh, I see. Of course. Old bones. Humph! Well," and Mr. Ranquist did not seem to know whether to smile or frown. "Well, my friend and I were not exactly looking for old bones. Old stones are more in our line. You see we came out here on a visit and thought we'd take a walk out this way. We've found a fine lot of old stones," and Mr. Ranquist motioned rather vaguely toward his companion. "What are you boys after, anyhow?" he finished, suddenly. "Nothing in particular," put in Roger, and at the sound of his voice, Mr. Ranquist turned quickly. "Oh, it's our friend of the post-office," he exclaimed. "I remember you now. How are you?" "Pretty well," replied Roger.