"What about these sea-boots," I asked, "and the place we are to find where he left them?" "We'll look for that now; and if we find it we can be pretty sure our mariner stole the dog." "You seem to be taking it for granted already," I pointed out. "The easiest way to prove he didn't is to satisfy ourselves that there's no evidence he did," said the oculist. "But I fancy he did." "From the way you've sized it up so far I should be inclined to back your fancy," I admitted frankly. "I take it, from your diagnosis, that our nautical friend came ashore here, went up on to the cliff, and glued his eye to the dining-room window. When he saw we were at dinner, and it was getting dusk--in fact, almost dark--he took off his sea-boots and slipped up to the Lodge in his stocking-soles. So if we climb the cliff, we expect to find the spot on which he deposited his boots." "If we expected that," Garnesk replied, "we should also expect to find his boots; and he wouldn't be likely to leave such incriminating evidence in our hands as that. No, my dear Ewart; when he left the cliff he was wearing his boots, and he left them at some point on the path between the house and his embarking place. Come--let's look." I was intensely interested in my friend's deductions, and I felt convinced that he was right. So we climbed the cliff, he by one route and I by another, in order to see if we could find any traces of last night's visitor. But that was impossible; the rocks were too storm-swept to harbour any sort of lichen which would have shown evidence of footmarks. Still, we were not disappointed when we reached the top, and Garnesk looked at me with a charming expression of boyish triumph when we came across a patch of ground where the heather had obviously been trampled about and worn down by someone recently lying there. "I don't think we'll worry about tracing him from here just now," said the specialist. "It would be a very difficult job, and we may as well make for the most likely spot to embark from." "Right you are," I agreed. "I think there can only be one--that is a secluded little inlet, almost hidden by the rocks on the other side of the house." "Come on, let's have a look at it," my companion urged; and we blundered down the side of the cliff and hurried along the shore. But when we came to the small bay which I had in mind there was certainly some sign of disturbance among the rough gravel with which the shore was carpeted; and that was all the evidence we could find. "It is such an ideal spot for the job that this almost knocks our theory on the head," murmured Garnesk ruefully. "There are no boat-marks, or anything." "Which, in a way, bears out your diagnosis," I cried, suddenly hitting on what I thought to be the solution of the difficulty. "How, in heaven's name?" "Our old friend the tide," I declared, with returning confidence.