“Quite so!” with another smile.
“How did you do it? Sit on it?”
“No, but you left the end of a string sticking out.”
“How do you know I did it?” asked Billy.
“Because you are the only fellow that uses green cord in tying up parcels. I have noticed that, among other things.”
“Billy is a bit green himself when it comes to playing jokes on observant boys,” remarked Harry.
“But how did you happen to come up here ahead of time?” asked Billy, paying no attention to Harry’s observation.
“Accident, that’s all. I wanted something.”
“But I did not see you leave the room,” said Billy. “You did not see me at work?”
“No, but I saw you come in. Even then I did not suspect anything. I was about to go up when you came in.”