After this they spent a considerable time wandering up and down a portion of the island, though Frank fancied that Mr. Barclay, who asked Harry a question now and then, had some purpose that guided him. The moonlight was too dim and the shadows among the trees too dense for him to follow a trail steadily, but he seemed to be prospecting for likely places where footprints or broken-down undergrowth might be found. At length they reached a little stony hollow, with a rock that rose some six or seven feet on one side and dark firs clustering close about it. Here Mr. Barclay stopped and looked about him before he turned to Harry. "Now," he said, "this is a spot that could be easily described and located by anybody who happened to be told about it. That rock would make a first-class mark. If you had anything to bury for somebody else to dig up, where would you put it?" Harry walked about the place, stepping carefully upon the stones and avoiding the scattered underbrush, until he reached a clump of withered fern. "Right here," he replied, and kneeling down pulled some of the yellow fronds about. Then he looked up sharply. "This stuff's very dead and it's lying flat," he exclaimed. "Farther on the stems aren't broken and some of them don't seem quite dried up yet." Frank acknowledged that these were things he would not have noticed, but Mr. Barclay nodded. "Somebody else may have fixed on the same spot as you have done," he said. "It's possible, though I don't think it's more than that. There might be half a dozen similar places on the island, but if you'll handle the fern carefully it wouldn't do any harm to make a hole." They had brought a light spade with them, and after Harry had cleared the ground Frank set to work with it. He had taken out only a few shovelfuls of soil and shingle when he gave a cry of surprise as he struck something that seemed more solid. Harry and Mr. Barclay stooped down beside him. The latter struck a match and lighted a piece of paper he took from his pocket, and before it went out Frank had cleared the soil away from the top of a small wooden case. "It's rather more than I could have reasonably expected," said Mr. Barclay, "but when you haven't much to act upon it's wise to make the most of what you've got and leave the rest to chance. Now you may as well shovel that dirt back." "Aren't you going to take the thing out?" Frank asked in astonishment. "No," replied Mr. Barclay, "I don't think it's necessary. It wouldn't be the first time I'd seen opium and we don't want to leave too plain a trail behind us. As we have spent some time on the island already, hadn't you better get to work?" Frank flung back the soil and when he had finished Harry replaced the loose fern which he had carefully laid aside. He did not, however, seem satisfied with the way he had arranged it and when he looked up at Mr. Barclay his manner was diffident. "I'm afraid I can't do any better in the dark," he said.