"It is the wooden-legged man."
"Quite so. But there has been some one else—a very able and efficient ally. Could you scale that wall, doctor?"
I looked out of the open window. The moon still shone brightly on that angle of the house. We were a good sixty feet from the ground, and, look where I would, I could see no foothold, nor as much as a crevice in the brick-work.
"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 climb 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 toward the end of the rope, from which I gather that he slipped down with such velocity that he took the skin off his hands."
"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 have already considered that possibility."
"How then?" I persisted.