Brooding thus, eye and ear were both alert for the faintest sight or sound. But from the interior of the cavern not a breath came. Once, from among the jagged rocks high on the west slope of Ben Einaval, he fancied he heard an unwonted sound--that of human laughter, but laughter so wild, so remote, so unmirthful, that fear was in his heart. It could not be other than imagination, he said to himself; for in that lonely place there was none to wander idly at that season, and none who, wandering, would laugh there solitary. It was with an effort that Alan at last determined to probe the mystery. Stooping, he moved cautiously into the cavern, and groped his way along the narrow passage which led, as he thought, into another larger cave. But this proved to be one of the innumerable blind ways which intersect the honeycombed slopes of the Isle of Caves. To wander far in these lightless passages would be to track death. Long ago the piper whom the Prionnsa-Bàn, the Fair Prince, loved to hear in his exile--he that was called Rory M'Vurich--penetrated one of the larger hollows to seek there for a child that had idly wandered into the dark. Some of the clansmen, with the father and mother of the little one, waited at the entrance to the cave. For a time there was silence; then, as agreed upon, the sound of the pipes was heard, to which a man named Lachlan M'Lachlan replied from the outer air. The skirl of the pipes within grew fainter and fainter. Louder and louder Lachlan played upon his chanter; deeper and deeper grew the wild moaning of the drone; but for all that, fainter and fainter waned the sound of the pipes of Rory M'Vurich. Generations have come and gone upon the isle, and still no man has heard the returning air which Rory was to play. He may have found the little child, but he never found his backward path, and in the gloom of that honeycombed hill he and the child and the music of the pipes lapsed into the same stillness. Remembering this legend, familiar to him since his boyhood, Alan did not dare to venture further. At any moment, too, he knew he might fall into one of the crevices which opened into the sea-corridors hundreds of feet below. Ancient rumour had it that there were mysterious passages from the upper heights of Ben Einaval which led into the heart of this perilous maze. But for a time he lay still, straining every sense. Convinced at last that the man whom he sought had evaded all possible quest, he turned to regain the light. Brief way as he had gone, this was no easy thing to do. For a few moments, indeed, Alan lost his self-possession when he found a uniform dusk about him, and could not discern which of the several branching narrow corridors was that by which he had come. But following the greener light, he reached the cave, and soon, with a sigh of relief, was upon the sun-sweet warm earth again.