"Of course I understand that, Sir Karl," was the ready answer. "There's no offence meant, and none taken. But if you could put yourself in my place, you'd see my difficulty. Upon my word, I never was so mystified before. _There Salter is_. Other people can see him, and have seen him; and yet, when I search I find no traces of him. A thought actually crossed my mind just now, whether there could be a subterranean passage from the Maze to Clematis Cottage, and that Salter makes his escape there to his cousin on occasion. I should like to search it." "Come and do so at once," said Karl, half laughing. "Nothing convinces like ocular demonstration. I give you full permission, as owner of the cottage; I doubt not Smith will, as its tenant. Come and ask him." The detective was in earnest, and they crossed over. Seeing them making for the gate, Mr. Smith came out of his house, pipe in hand. It was one of those long churchwardens. Karl spoke a few words of explanation. Mr. Detective Tatton suspected there might be secret rooms, or doors, or fugitives hidden in Clematis Cottage, and would like to search it. After the first momentary look of surprise, the agent remained unruffled. "Pass on, sir," said he, extending the thin end of his pipe to indicate the way. "You are welcome. Go where you please: search into every nook and corner; up the spouts and down the drains. If you surprise old Betty, tell her you're the plumber." Mr. Strange took him at his word. Karl and the agent waited in the sitting-room together. "Is it after Sir Adam, sir?" breathed the agent. "No. No suspicion of him. It's after the other I told you of. Hush! Better be silent." The agent put his pipe away. Karl stood at the open window. Old Betty, the ancient servant, came in with a scared face. She was a little deaf, but not with a deafness like Hopley's over the way. "It's all right, Betty," called out her master. "Only looking to the drains and spouts." Satisfied in one sense of the word--for in truth it was readily seen by the most unprofessional eye that there were no means afforded for concealment in the shallow-built cottage--the officer soon joined them again. He had not had really a suspicion of the cottage, he said by way of apology: it was merely a thought that crossed him. Mr. Smith, however, did not seem inclined to take the matter quite indifferently now, and accosted him. "Now that you are satisfied, sir, perhaps you will have no objection to tell me who the individual may be, that you have fancied I would harbour in my house. I heard before from Sir Karl that you were after some one." From the tone he spoke in, a very civil tone, tinged with mockery, the detective caught up the notion that Smith already knew; that Sir Karl must have told him: therefore he saw no occasion for observing any reticence.