For any use they were to me, however, I might as well have left them behind. Try as I would, I was quite unable to fix my attention on what I was reading, and in a very little while I gave up the attempt in despair, and finally abandoned myself to my own thoughts. Now that I had done everything I could I was once more beginning to feel intensely worried about Christine. Not a word or message had come from her since she had disappeared into the fog at Pen Mill, and knowing, as she must have done, the state of anxiety I should be in, this complete silence was all the more ominous and suggestive. The murder of Bascomb and the facts which Campbell had discovered with reference to Manning's past history added to my misgivings. Except for the poor protection afforded by her uncle and the old French servant, she was at the mercy of one of the most cunning and pitiless scoundrels who had ever escaped the gallows. Every evil impulse in his nature must have been roused to life by the events of the previous afternoon, and still more bitterly than before I cursed my own folly and weakness in ever having permitted her to leave the island. I was sitting there gnawing my lip and staring at the empty grate when a sudden sound in the verandah outside attracted my attention. Faint as it was, every muscle in my body stiffened instinctively. In one rapid movement I whipped out Manning's revolver, and the next moment I was crouching forward, my eyes fixed on the shutters. For perhaps a couple of seconds the silence remained unbroken. Then, clear and unmistakable, came a low whistle, followed almost immediately by two sharp taps upon the pane. CHAPTER SIXTEEN By a great effort of will I remained exactly as I was. I had to decide what to do, and I had to decide in a hurry, but it was obviously one of those situations in which one could not afford to make the least mistake. If I called out, the answer, for all I knew, might take the shape of a Mills bomb. On the other hand, if I kept silent, how could I discover the identity of my visitor? _Tap, tap, tap._ Once again came the mysterious summons--this time more imperative than before. As the last knock died away, an idea flashed into my mind. Rising to my feet, I moved stealthily across the hall, and, creeping up the staircase like a cat, I turned into my own bedroom, which looked out on the front of the house. The window was still open, and, advancing towards it with infinite care, I was just preparing to make a cautious reconnaissance when I suddenly heard a shuffling movement down below. I paused, and, almost at the same second the loud jangling peal of the front door bell echoed up from the kitchen. Somehow or other, the sound acted on me like a tonic. Without hesitating any longer, I thrust my head out over the sill, and there, right underneath me, I saw the ragged, curly-haired figure of my little friend, Jimmy. "Hullo, James," I called out, "what are you doing here?"