"I cannot keep awake," I said. "Nor can I," he answered, "and yet I have spent nights and nights of my life in signal-boxes and never was the least bit drowsy; perhaps it's the cold." "Perhaps it is," I said; "but I have been out on as freezing nights before, and----" The man did not reply; he had sat down again; his head was nodding. I was just about to go up to him and shake him, when it suddenly occurred to me that I might as well let him have his sleep out. I soon heard him snoring, and he presently fell forward in a heap on the floor. By dint of walking up and down, I managed to keep from dropping off myself, and in torture which I shall never be able to describe, the night wore itself away. At last, towards morning, I awoke Henderson. "You have had a good nap," I said; "but never mind, I have been on guard and nothing has occurred." "Good God! have I been asleep?" cried the man. "Sound," I answered. "Well, I never felt anything like it," he replied. "Don't you find the air very close, sir?" "No," I said; "it is as fresh as possible; it must be the cold." "I'll just go and have a look at the light at the tunnel," said the man; "it will rouse me." He went on to the little platform, whilst I bent over the fire and began to build it up. Presently he returned with a scared look on his face. I could see by the light of the oil lamp which hung on the wall that he was trembling. "Mr. Bell," he said, "I believe there is somebody or something down at the mouth of the tunnel now." As he spoke he clutched me by the arm. "Go and look," he said; "whoever it is, it has put out the light." "Put out the light?" I cried. "Why, what's the time?" Henderson pulled out his watch. "Thank goodness, most of the night is gone," he said; "I didn't know it was so late, it is half-past five." "Then the local is not due for an hour yet?" I said. "No; but who should put out the light?" cried Henderson. I went to the door, flung it open, and looked out. The dim outline of the tunnel was just visible looming through the darkness, but the red light was out. "What the dickens does it mean, sir?" gasped the Inspector. "I know the lamp had plenty of oil in it. Can there be any one standing in front of it, do you think?" We waited and watched for a few moments, but nothing stirred. "Come along," I said, "let us go down together and see what it is." "I don't believe I can do it, sir; I really don't!" "Nonsense," I cried. "I shall go down alone if you won't accompany me. Just hand me my stick, will you?" "For God's sake, be careful, Mr. Bell. Don't go down, whatever you do. I expect this is what happened before, and the poor fellows went down to see what it was and died there. There's some devilry at work, that's my belief."