"What was the object of the opening and closing of the garage doors at the Red House?" I asked, almost mechanically. "Simple enough," Gatton replied. "Whereas here the telephone was installed, so that the bell could be rung by some one merely calling up your number--and the ringing stopped by the caller telling the exchange he had made a mistake--in the Red House, as I have discovered, the 'phone had been disconnected shortly after Dr. Brown-Edwards left the place." "Then the opening and closing of the doors was merely a device for ringing the bell?" "Yes. The opening of the first door set it ringing and the opening of the second probably stopped it. Mr. Addison," he stood up, resting his hands upon the table and regarding me fixedly--"we enter upon the final battle of wits: New Scotland Yard _versus_ Dr. Damar Greefe and the green-eyed lady of Bâst. Regarding the latter--there is a very significant point." "What is that?" "The 'voice' on this last occasion was that, not of a woman, but of a man." CHAPTER XXIII THE INEVITABLE "I very much regret having to trouble you, Miss Merlin, at such a time," said Inspector Gatton, "but as the paper lodged with you by the late Sir Eric Coverly may throw some light upon a very dark matter, perhaps you will read it to us." I watched the play of expression upon Isobel's face with a depth of sympathy which I cannot attempt to describe. The successive trials which had been imposed upon her in so short a time had robbed her cheeks of their sweet color and there were dark shadows under her eyes. The tumult of my own feelings was such that I was scarcely capable of consistent thought nor had I the moral courage to examine those emotions which stirred so wildly within me. Late on the previous night I had performed the unhappy duty of breaking to her the news of Coverly's dreadful death. I shall never forget that black hour. Her courage, however, under all these trials had been admirable, and although I well knew what it must have cost her, she replied now with perfect composure: "Look--I took it out of my bureau when I heard that you were here, Inspector." She took up from the table a foolscap envelope sealed and having her name written upon it in large and somewhat unsteady characters. "I would suggest," said Gatton, with a delicacy which earned my gratitude, "that you read it yourself first, Miss Merlin. If there is anything helpful in it you can then communicate it to me." I saw Isobel biting her lip hard, but she resolutely tore open the envelope; and leaving her to read the contents, I joined Gatton at the window. We both stood staring out for what seemed a very long time, then: "It is rather long," said Isobel in a low voice.