He stood for a moment, staring incredulously into it. Then he hurled it down on the table and turned on me, as I stood beside him. "It's a trick!" he said furiously. "You've hidden it somewhere. This is not my bag. You've substituted one just like it." "Don't be a fool," I retorted. "How could I substitute an empty satchel for yours when up to fifteen minutes ago I had never seen you or your grip either? Use a little common sense. Some place to-night you have put down that bag, and some clever thief has substituted a similar one. It's an old trick." He dropped into a chair and buried his face in his hands. "It's impossible," he said after a pause, while he seemed to be going over, minute by minute, the events of the night. "I was followed, as far as that goes, in Plattsburg. Two men watched me from the minute I got there, on Tuesday; I changed my hotel, and for all of yesterday--Wednesday, that is--I felt secure enough. But on my way to the train I felt that I was under surveillance again, and by turning quickly I came face to face with one of the men." "Would you know him?" I asked. "Yes. I thought he was a detective, you know I've had a lot of that sort of thing lately, with election coming on. He didn't get on the train, however." "But the other one may have done so." "Yes, the other one may. The thing I don't understand is this, Mr. Knox. When we drew in at Bellwood Station I distinctly remember opening the bag and putting my newspaper and railroad schedule inside. It was the right bag then; my clothing was in it, and my brushes." I had been examining the empty bag as he talked. "Where did you put your railroad schedule?" I asked. "In the leather pocket at the side." "It is here," I said, drawing out the yellow folder. For a moment my companion looked almost haunted. He pressed his hands to his head and began to pace the room like a crazy man. "The whole thing is impossible. I tell you, that valise was heavy when I walked up from the station. I changed it from one hand to the other because of the weight. When I got here I set it down on the edge of the porch and tried the door. When I found it locked--" "But it wasn't locked," I broke in. "When I came down-stairs to look for a burglar, I found it open at least an inch." He stopped in his pacing up and down, and looked at me curiously. "We're both crazy, then," he asserted gravely. "I tell you, I tried every way I knew to unlock that door, and could hear the chain rattling. Unlocked! You don't know the way this house is fastened up at night." "Nevertheless, it was unlocked when I came down."