“Now I am interested. What you have told me shows that there’s something up, something very mysterious. “I think we’d better keep our eyes on it, Patsy.” “Well?” “Go back to the hotel and get on Snell’s track. Follow him across the continent if necessary, and keep me posted.” “All right, boss.” “Better take a cab. Leave your grip in it until you know what station Snell is going to. Then stick to him like a burr. There may be more attempts against his life.” Patsy was gone in a minute. When his cab halted at the Fifth Avenue he did not leave it, for he saw Snell coming out. The man got into a hotel carriage, and told the driver to take him to the Pennsylvania Railroad station. This was done, and, of course, Patsy followed. Snell bought a ticket for Chicago, and Patsy, who stood close behind him at the window, did the same. They were almost side by side as they went to the ferry-boat, Patsy, of course, so disguised that Snell did not recognize him. Snell went to the forward end of the boat and stood near the rail. The detective sat down in the men’s cabin. Hardly had he taken his seat when a man came aboard whom he had seen before. It was the one whom he had suspected as shadowing Snell from Nick Carter’s house. CHAPTER III. A GAME OF WATCHING. Patsy thought that this was the same man who had come so near killing Snell. He had not been sure of that at the time, for he had not been able to see the would-be murderer’s face. Now it took only a sharp glance to satisfy him, for the man’s motions were a little peculiar. He had a way of bending his head to one side which Patsy had noticed in the man who had shadowed Snell. As he remembered it the same sideways hang of the head had been the case with the would-be murderer in that instant when he saw him darting after his victim. “So,” thought Patsy, “he’s at his game again. Been watching Snell, probably, ever since the attack. There’ll be trouble if he finds his man on board.” Nothing could have been plainer than that the man was looking for somebody. He went part way through the cabin, giving stealthy, side glances at the men on the seats. When he came to the doorway that led to the upper deck, he went up. “He won’t find Snell up there, I think,” said Patsy to himself, as he got up and went forward. The detective went as far as the door that opened upon the forward deck. Looking through it, he saw Snell leaning against the rail. Nobody else was out there. At that moment the boat had hardly got beyond the end of the ferry slip. Patsy sat down where he could look the length of the men’s cabin and also glance through the glass in the door at the forward deck. In less than a minute he saw the stranger coming down the stairs from the upper cabin. He was still walking slowly, and peering sharply at the passengers. When he had come as far as the door, he halted and looked through the glass.