The sound of the leader’s rough voice came to him, evidently asking a question. “Is the trick done?” or something of that sort. He could imagine the men’s short answer. Then probably the gang got down to business again with Snell and Leonard. It would do no good to try to tell what Patsy’s thoughts and feelings were. He had been unlucky enough before to get captured by men who meant to kill him. On other occasions he had worked himself free, or Nick or Chick had come just in time to rescue him. Nick was thousands of miles away. Chick wasn’t on this strange case at all. The cords upon his hands and legs were very firm. And yet the young man felt no despair. “Somehow!” he thought, and he went to rubbing his back as well as he could against the hard cellar floor. He thought he might wear the cords through in time. In time—good Heaven! would there be time? What was that he smelled? An enemy more fearful than the bullets of assassins. He understood now what he had been doing when the man had been feeling along the way. The villain had been hunting for the gas jet. He had found it and turned the cock “full on!” The close cellar was filling rapidly with the poisonous stuff. Patsy’s throat tickled. He coughed and partly dislodged his gag, but it was only to take more gas into his lungs. With all his might he wriggled so that the cord might be cut or worn enough to break. He could make no effect on it, so far as he could tell. Every strain simply made the cord cut deeper into his flesh, and he was as helpless as before. The poisoned atmosphere choked him. He felt his head whirling. The whole house seemed to be going around and around. In the confusion of his mind he seemed to hear voices in a loud discussion. They ceased—there was no sound—except a fearful roaring as if he lay at the bottom of Niagara Falls. And then, a dreadful feeling that he might as well give it all up. A man had to die some time. One time was probably as good as another. He had done what Nick told him to as well as he knew how. He hoped that Nick and Chick would somehow get at this gang. Patsy was very tired and sleepy. The whirling and the noises ceased. His brain was at rest. CHAPTER VII. THE MYSTERY OF GEORGE SNELL. Nick Carter had said good-by to his bright young assistant at about half-past ten of an evening. He gave little further thought to the case that night, for he knew that it was in good hands. “I shall probably hear from the boy in the morning,” he thought, as he went to bed. No message came from Patsy in the morning, because the young man had been too much occupied in watching Snell and Leonard in the Jersey City station to send one. But a message came from Dinsmore that gave Nick a bit of a surprise. It was as follows: