Excerpt: ...the surface, would have filled and sunk very rapidly. "There, you see an attempt to prepare a victim for the sacrifice," I heard him saying, more to himself than to me, "two victims rather," he added as he bent over and ran his fingers along the slit. I began to whistle-a thing I always do unconsciously when utterly nonplussed-and purposely paid no attention to his words. I was determined to consider them foolish. "It wasn't there last night," he said presently, straightening up from his examination and looking anywhere but at me. "We must have scratched her in landing, of course," I stopped whistling to say. "The stones are very sharp." I stopped abruptly, for at that moment he turned round and met my eye squarely. I knew just as well as he did how impossible my explanation was. There were no stones, to begin with. "And then there's this to explain too," he added quietly, handing me the paddle and pointing to the blade. A new and curious emotion spread freezingly over me as I took and examined it. The blade was scraped down all over, beautifully scraped, as though someone had sand-papered it with care, making it so thin that the first vigorous stroke must have snapped it off at the elbow. "One of us walked in his sleep and did this thing," I said feebly, "or-or it has been filed by the constant stream of sand particles blown against it by the wind, perhaps." "Ah," said the Swede, turning away, laughing a little, "you can explain everything." "The same wind that caught the steering paddle and flung it so near the bank that it fell in with the next lump that crumbled," I called out after him, absolutely determined to find an explanation for everything he showed me. "I see," he shouted back, turning his head to look at me before disappearing among the willow bushes. Once alone with these perplexing evidences of personal agency, I think my first thoughts took the form of "One of us must have done this thing, and it certainly was not I." But my...