The horror of my dream on Christmas Eve came back to me as I read. No doubt there had been many river mysteries and "shocking discoveries" in the Thames, and perhaps I had read of them, dismissing them from my mind with the alacrity with which one does rid one's thoughts of such sordid tragedies, when they do not happen to concern oneself or one's acquaintances. But this tragedy I could not so dismiss. I could even picture the very spot where the boys must have seen the sack caught among the dry and rattling reeds. "A small backwater leading out of a larger one, between Great Marlow and Purley Lock." The larger one was doubtless that on which Carson Wildred's house was situated; the smaller one--a mere alley of water, leading away under a drooping tangle of willow and chestnut branches--one had to pass in walking from Purley to the House by the Lock. I was sure, as I recalled the place in memory, that the scene of the discovered mystery could have been no other than this. Having read to the end, I folded up the paper and put it away in a pocket of my greatcoat for future reference. Then I began walking slowly on towards the Savoy Hotel. Had it not been for the odd chance which had induced two boys to stroll, in the middle of winter, along the bank of an insignificant outlet of a Thames backwater, what a fine place, I told myself, this would have been for the concealment of a crime! Even without the weights, which had probably become detached from the sack by tangling among the roots under the surface of the water, the body might have been expected to remain hidden for months--at least, till the coming of the spring. Then, as I so reflected, my mind turned to darker thoughts. Had a crime been committed by the inhabitants of the House by the Lock, what a convenient hiding-place would that adjacent waterway have been! I had no reason to fancy that such a crime had been done, and yet--my thoughts went back to the day on which I paid my somewhat memorable visit to Wildred and Farnham. Suddenly came the recollection of the awful cry I had heard as I waited in the curious octagonal room, looking at the covered portrait of Karine. The sound had been explained, but there had been a certain flurry and clumsiness in the explanation, I had thought, even then. I remembered the smoke and sparks which had so mysteriously risen from the tower, and the heat of the octagonal room adjoining it. All this, too, had been accounted for. I had not cared at the time to invent romances to fit into the strange appearances, which I had assured myself were doubtless strange only in appearance; but now I could not help dwelling upon them with an almost morbid persistency that would not be set aside.