Roger was greatly disappointed. But he comforted himself with the reflection that, at least, he was on the track of the mystery. He thought quickly and realized that some older head than his must take up the problem now. Yet whom could he tell? Mr. Kimball, he reasoned, would hardly be in a position to give an expert opinion as to what was under the earth. Then, too, he did not want to raise false hopes for his uncle that might be shattered after investigation. He could not imagine what it was the men had found, that they regarded as of such value. They evidently expected to find it, which added to the complications. How did they know at about that spot something was hidden under the surface? Clearly it must be some mineral substance Roger thought, but what? It didn't seem to be gold, unless it was in some peculiar form. Whatever it was, would it be worth the trouble that might be necessary before it could be come upon and dug out, unless some one, who knew just what they were searching after, did the work? And it was evident that the two men did possess this knowledge, which was so needful. Roger was in a dilemma, but he resolved to discover a way out, if possible. Carefully marking the location of the stake, that he might find it again, he started home. He came into the vineyard just as his cousin was clearing up the last of the brush. "Well," said Adrian, "I thought maybe you had gone to the house." "No," answered Roger, "I was just walking in the woods for my health," and he smiled a little. For certain reasons he did not want even Adrian to know what he had seen. "We'll take a long walk to-morrow," said Adrian, breaking into a merry whistle. "But something tells me it is nearly supper-time. I'm as hungry as a bear. Hi, Jack!" he called to the dog, and all three started for home, Roger in a sort of day-dream over what he had discovered. CHAPTER XVIII A BIG BLACK BEAR Roger said nothing to the folks at the house of what he had observed. He had a plan, partly worked out in his mind, and he wanted to see whether or not he could accomplish anything before he told his uncle or cousin. He resolved to wait until after the next day and observe what happened when he and Adrian went to guide Mr. Dudley and Mr. Ranquist over the hills, for Roger shrewdly suspected that the men required no piloting to find what they sought. However, he thought it was not necessary to mention that to any one. At the time appointed he and Adrian presented themselves at the Pine Tree Inn and asked for the two engineers. Mr. Ranquist came down. "Ah," he said, looking at his watch and smiling, "you are prompt, I see. Mr. Dudley and I will be with you in a few minutes." In a little while the two men appeared, both dressed in rough clothes suitable for a tramp through the woods.