"Don't be a fool," I answered. "There's a submerged rock right across here. You couldn't miss it. Climb down, do you hear?" His arms fell to his sides. For a single moment he stood there, immovable. Not even his youth, his bathing costume, and the clear background of blue sky and sunlit air could lend him any grace of form or outline. He seemed, indeed, from his short neck and hunched shoulders, as he turned away, almost deformed. I looked all around. There was no sign anywhere of Duncombe. I raised my voice and shouted. "Hello, Duncombe!" I heard a splash, as though he had slipped off the ledge of the rock behind me. Presently he came swimming round the corner. "What's the matter?" he shouted. "And where's Arthur?" "He's climbing down from that rock," I answered, as Duncombe came alongside. "I've just stopped his diving into this pool." "Why?" He was by my side now and I pointed downwards to the dark line of cruelly jagged rock. He looked for a moment concerned. "Jove, I've never noticed those!" he muttered. "They're barely three feet," I answered. "I can reach them." Duncombe turned over on his back. We were in the shadow, almost surrounded by rocks. The voices of the others, preparing the lunch, sounded a long way away. I suddenly felt as though I were cut off, as though I could read the thoughts at the back of this man's brain, as though I myself were in danger. All the time he was drawing a little closer to me. Leonard and Ella Duncombe suddenly appeared upon the summit of one of the lower ranges of rocks. "Come along to lunch," the former shouted. The moment had passed. Duncombe began to swim vigorously for the shore. He was quite himself when he stepped out on to the sand. "I wouldn't make a fuss about that, if I were you, Lister," he suggested. "It looks as though I weren't careful enough. As a matter of fact, I don't think the boy would have come to any harm." Arthur was seated by himself on the sands, his arms clenched around his knees, his face turned away from all of us. He seemed to have ignored the summons to prepare for lunch. "Probably not," I answered, trying to speak in as unconcerned a tone as possible. "Boys and drunken men have a wonderful knack of avoiding accidents." We strolled up the beach together. Duncombe paused and spoke to Arthur. "Come along," he said, "they're waiting luncheon for us." Arthur turned and looked at him. I could not say that there was anything either malicious or reproachful in that look, and yet it worried me. He made no answer in words. A few moments later, however, he scrambled to his feet and went to the rock behind which his clothes were lying.