"Professor Punjab is planning to get possession of the miner's money," he said in whispers, as the three boys held an impromptu conference in the lavatory, where Nat and Jack had gone to clean their teeth before retiring. "How's he going to do it?" asked Jack. "He has told Mr. Post that he has the power of making money increase over night," John explained. "He says if a certain sum is put in a mysterious box which he has, it will be doubled in the morning." "And the miner believed him?" asked Jack. "Sure. He agreed to put his roll in the box the fakir has, and it is to be placed under Mr. Post's berth. He is not to open it until morning." "And when he does it will be full of brown paper," said Jack. "I've read about such tricks." "It won't if we can help it," put in Nat. "I guess here is where we get busy." The boys held a further conference and agreed on a plan of action. They went back to their berths, and, a little later, they heard the fake professor and Mr. Post coming back from the smoking room. "Do I put it at the head or foot?" they heard the miner ask. "At the foot," replied the plotter. "So he can get it easier," muttered Jack. Nat's berth was right opposite that of Mr. Post, so it was arranged he was to do the main work. In a little while the sleeping car became a quiet place, and deep breathing from one berth after another told that the occupants were slumbering soundly. Pretty soon Nat heard a snore from the berth of the miner. "I'd better do it now, before Professor Punjab gets busy," he thought. Then with his umbrella, which had a crook for a handle, Nat reached out between the curtains and began to feel around under Mr. Post's bed for the box. He had to work cautiously, but at length his efforts were rewarded. He felt the umbrella crook fasten on the object, and he pulled it across the aisle toward him. When it was near enough he reached his hand down and took it up into his berth. "Have you got it?" asked Jack in a whisper from the next sleeping compartment. "Sure," replied Nat "Take out the money and put in our messages," Jack added, and Nat did so. Then he placed the box back where he had found it. In a short time the three boys, who were watching from behind their berth-curtains, saw a hand protrude from beneath the hangings around Professor Punjab's bed. The hand felt around a bit, and then went under Mr. Post's berth. In a few seconds it came out and the box was in it. A moment later it moved back again, and seemed to replace the box. "That's where he put a dummy in place of what he thinks is the one with the bills in," thought Nat, who was watching closely. "He'll skip out soon, I guess." His conjecture was right. A few minutes later Professor Punjab, who had not undressed, stole from his berth and walked softly to the end of the car. "I wonder if he'll jump off," thought Nat.