"Why do you wish to extract this promise from me?" I demanded dubiously. "Because--well, because you must give it. You _must_ remain silent, Holford. It is imperative!" "You really ask too much of me," I laughed sarcastically. "I know the ghastly truth. You showed it to me of your own accord--you yourself drew me into this dark, mysterious affair, and now you coolly demand my silence, because you are, I suppose, interested in the money realised by the sale of Professor Greer's secret." "Ethelwynn Greer makes the same demand as myself," he said calmly. "Surely you don't believe that the girl has participated in any shamefully obtained profits?" "The girl saw her father dead, and now refuses to admit it," I responded. "How do you know that she did?" he asked. "What actual evidence have you upon that point, beyond my word--repeated from the story told to me by Antonio?" "Ah! so Antonio is changing his tale in order to fit the new order of events--is he?" "Well," Kirk said, after a brief pause, "that there is a new order of events--as you put it--I admit. Yet, whatever they may be, your silence, Holford, as well as mine, is imperative. You hear that!" he added, looking straight into my face. "To hear and to heed are scarcely synonymous," I remarked in anger. I was incensed with this man who refused to give me any satisfaction concerning Mabel, and yet commanded my silence. Was it not a very curious feature of the affair, I reflected, that Ethelwynn had ingeniously approached me, offering me news of Mabel in return for my undertaking to make no further inquiry into her father's secret death? How much did Langton know, and what was the extent of the knowledge of that friend of his, the specialist in diseases of the throat and nose? For a few moments I sat in silence, longing for the return of the bogus Professor, the man whom I had followed through Edinburgh and Glasgow, yet who had so very cleverly escaped my vigilance. I was anxious to meet him, and to see what kind of man he could be. As an impostor he was, it seemed, shameless and bold beyond human credence. How many thousands had Edwards and Sutton paid to him for that great secret that was not his own? Antonio, suave and cringing, suddenly put his head in at the door, asking: "Did you ring, signore?" "No!" I cried, rising angrily, "Mr. Kirk did not ring. I suppose you've been listening outside--eh? You are one of the accomplices in the murder of your master--and by Heaven, you shall pay for it! If Scotland Yard will not help me, then I'll take the law into my own hands and give the public an illustration of the red-tape and the uselessness of the police!" "The signore is a little excited!" was the man's quiet remark to Kirk. "Excited, by Heaven!" I cried. "I'll be fooled no longer by any of you--band of assassins that you are! You ask me to believe that black is white, and tell me that my own eyes deceive me. But I'll be even with you yet--mark me!"