"But how did you do it? I cannot think how it was."
"Easy enough. I had five pounds that my aunt sent me. I am a favourite with her"—and Dobson smiled complacently. "Well, I had that in my pocket, and when you handed me over the other note, after I picked up his pocket-book, I must have put the wrong note in, that is all."
"But what did you do with the one I gave you?" demanded Elgert quickly.
"Changed it up in the town."
"Changed it!" he gasped. "You idiot! Don't you know that it can be traced by its number? I suppose that you wrote your name on the back?"
"Of course I did," said Dobson, looking very scared.
"Yes, and that note will come back to you, perhaps brought by a constable. You have done a nice thing!"
"But I didn't steal it—you stole it!" cried Dobson, in alarm. And Elgert struck him a savage blow.
"So you would turn sneak, would you? Well, there is no proof that I stole it. There is plenty of proof that you had it, changed it, and put your note into the pocket-book. You will suffer, and not me."
"What—what can we d-d-do?" gasped Dobson, his knees knocking together. And Elgert answered—