I looked at the shingly beach, and saw the keel-marks of a boat and the footprints of its occupants in the middle of the cove. We went up gingerly, for fear of disturbing the ground of our investigations. I looked at the marks, and pondered them for a moment. By this time my senses were wide awake. "What do you make of it?" the oculist asked. "Well," I replied, with an apologetic laugh, "I'm afraid you'll think me more picturesque than businesslike if I tell you all the conclusions I've already come to; but the man who came ashore in this boat didn't steal Sholto." "Go on," he said. "Why, I told you I knew you weren't a fool." "Thank you!" I laughed. "It seems to me that if a man arrived in a boat and went ashore to steal a dog, he would go away again in the same boat." "And didn't he?" "I feel convinced he didn't," I replied, and pointed out to him what must have been obvious to both of us. "Compare the keel-marks with high-water mark. There is less than half a boat's length of keel-mark, and it is just up above high-water mark. This craft, which appears to have been a small rowing-boat, was run ashore at high tide, or very near it, and run out again very quickly. It might conceivably have come in and been caught up by the sea. But Sholto was stolen between a quarter past eight and half-past nine, when the tide was well on the way out. If Sholto went out to sea it was not in this boat." "Well," said Garnesk, thoughtfully, "your point is good enough for me. We must look somewhere else." "I hope my attempts at detective work will not put us off the scent," I said, doubtfully. "I don't think they will, Ewart," said my companion, graciously. "Not in this case, anyway. I'm sure you're right, because this bay can be seen from the top windows of the house." "You evidently reached my conclusions with half the effort in half the time," I laughed. "Oh, nonsense!" he exclaimed. "It was you who pointed out that the one man in this boat came in daylight." "Why 'one man' so emphatically?" I asked. "When two men come in a boat to commit a theft, and only one of them goes ashore, the other would hardly be expected to sit in the boat and twiddle his thumbs. It's a thousand pounds to a penny that he would get out and walk about the beach. Now, only one gentleman came ashore from this boat, and only one got on board again. One set of footprints going and one coming decided me on that. Besides, if anyone came along and saw a solitary man sitting in a boat, they might ask him how his wife and children were, and he would have to reply; whereas an empty boat, being unable to answer questions, would raise no suspicions." "You seem to be arguing that this boat may have been the one we are looking for," I pointed out; "and yet we are agreed that the state of the tide made it impossible for Sholto to have been taken away in it."