“Mr. Ludgrove is dead,” replied the Black Sailor, almost gently. “Surely you remember the warning I gave you when we last met? Mr. Ludgrove, the herbalist of Praed Street, is dead. Nobody on this side of the grave will ever see him again. But you shall not be disappointed, Dr. Priestley. He was to have explained to you many things that seemed obscure, but were in reality very simple. It is only fitting that I should take his place.” And then at last the Professor understood. Perhaps it was some note in the man’s voice that gave him the clue. The solution was so simple that he could have laughed aloud at his own lack of perception. “You are Mr. Ludgrove,” he said simply. The Black Sailor laughed quietly, and the laugh and the voice in which he replied were those of the herbalist. “So you have guessed at last, Dr. Priestley!” he exclaimed. “Oh, but it was so simple! A little dye, which could be applied or removed in a few minutes, a little grease-paint for the scar, an artistic disarrangement of my beard and hair, a change of clothing, and who would recognize Mr. Ludgrove the herbalist? Still, the Black Sailor was careful only to appear in the half light. His disguise might have been penetrated under more searching conditions. But I flatter myself that it is effective.” The Professor, looking at the man, was forced to agree. Even now that he knew, he found it difficult to recognize the venerable Mr. Ludgrove with his well-kept, snowy beard, his kindly smile, and his large spectacles, in this wild-looking sailor with the fierce face and the tangled black hair which seemed to cover it. The disguise was undoubtedly effective, but—how simple! “Mr. Ludgrove is dead. His mission is completed, and you will never see him again,” continued the Black Sailor. “Let us do his memory the justice of saying that he told the truth. When Copperdock saw the Black Sailor, it was perfectly correct for Ludgrove to say that he and Copperdock were alone in the street. Ludgrove was the Black Sailor that evening. But this is beside the point. Pray sit down, Dr. Priestley, and we will enter upon the explanation which I have to give you.” Dr. Priestley’s mind had been working rapidly while the man spoke, and it appeared that he had guessed the Professor’s thoughts. “Perhaps I should explain the conditions,” he continued. “All the entrances to this room are securely fastened. The door is locked, and, as you see, there is a heavy curtain across it. The window is boarded up, and there are no other openings. If you were to shout as loud as you cared, no one could possibly hear you. Please do not think I wish to threaten you, Dr. Priestley, but I would point out that if you were so unwise as to attempt personal violence, I am a very much more powerful man than you, and I am armed. I am afraid that there is no alternative for you but to listen to what I say. And after that will come release. Now, surely you will sit down, Dr. Priestley.”