“It is absolutely impossible,” I answered.
“Without aid it is so. But suppose you had a friend up here who lowered you this good stout rope which I see in the corner, securing one end of it to this great hook in the wall. Then, I think, if you were an active man, You might swarm up, wooden leg and all. You would depart, of course, in the same fashion, and your ally would draw up the rope, untie it from the hook, shut the window, snib it on the inside, and get away in the way that he originally came. As a minor point it may be noted,” he continued, fingering the rope, “that our wooden-legged friend, though a fair climber, was not a professional sailor. His hands were far from horny. My lens discloses more than one blood-mark, especially towards the end of the rope, from which I gather that he slipped down with such velocity that he took the skin off his hand.”
“This is all very well,” said I, “but the thing becomes more unintelligible than ever. How about this mysterious ally? How came he into the room?”
“Yes, the ally!” repeated Holmes, pensively. “There are features of interest about this ally. He lifts the case from the regions of the commonplace. I fancy that this ally breaks fresh ground in the annals of crime in this country,—though parallel cases suggest themselves from India, and, if my memory serves me, from Senegambia.”
“How came he, then?” I reiterated. “The door is locked, the window is inaccessible. Was it through the chimney?”
“The grate is much too small,” he answered. “I had already considered that possibility.”
“How then?” I persisted.
“You will not apply my precept,” he said, shaking his head. “How often have I said to you that when you have eliminated the impossible whatever remains, however improbable, must be the truth? We know that he did not come through the door, the window, or the chimney. We also know that he could not have been concealed in the room, as there is no concealment possible. Whence, then, did he come?”
“He came through the hole in the roof,” I cried.
“Of course he did. He must have done so. If you will have the kindness to hold the lamp for me, we shall now extend our researches to the room above,—the secret room in which the treasure was found.”