He left the beach with the boys, but they dropped behind him and let him take the lead when they reached the scrubby firs which were scattered more or less thickly about the rocky ground. Frank fancied that Harry had some reason for doing this and the supposition was confirmed when Mr. Barclay stopped a moment beside a brake of withered fern and then, after stooping down, carefully skirted it as he went on again. The sky was clear, and though the moon was in its first quarter it shed a faint elusive light.
"That man can shoot, and it looks as if he was quite as smart at picking up a trail," said Harry in a low tone. "Anyway, if I'd been looking for a stranger's tracks I'd have tried yonder fern and I'd have been as particular not to smash any of it down as he was. I've an idea he must have chuckled sometimes when I got guying him." He paused and added thoughtfully, "It's the kind of fool thing you're apt to do unless you're careful."
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.