"Look here, sister, you just put the case into my hands and let me work it up. I wont say anything to Ben till you give the word; but I'll watch him, and now my eyes are open, it wont be easy to deceive _me_." Thorny was evidently pleased with the new play of detective, and intended to distinguish himself in that line; but when Miss Celia asked how he meant to begin, he could only respond with a blank expression: "Don't know! You give me the keys and leave a bill or two in the drawer, and may be I can find him out somehow." So the keys were given, and the little dressing-room where the old secretary stood was closely watched for a day or two. Ben cheered up a trifle, which looked as if he knew an eye was upon him, but otherwise he went on as usual, and Miss Celia, feeling a little guilty at even harboring a suspicion of him, was kind and patient with his moods. Thorny was very funny in the unnecessary mystery and fuss he made; his affectation of careless indifference to Ben's movements and his clumsy attempts to watch every one of them; his dodgings up and down stairs, ostentatious clanking of keys, and the elaborate traps he set to catch his thief, such as throwing his ball in at the dressing-room window and sending Ben up the tree to get it, which he did, thereby proving beyond a doubt that he alone could have taken the money, Thorny thought. Another deep discovery was, that the old drawer was so shrunken that the lock could be pressed down by slipping a knife-blade between the hasp and socket. "Now it is as clear as day, and you'd better let me speak," he said, full of pride as well as regret, at this triumphant success of his first attempt as a detective. "Not yet, and you need do nothing more. I'm afraid it was a mistake of mine to let you do this; and if it has spoiled your friendship with Ben, I shall be very sorry; for I do not think he is guilty," answered Miss Celia. "Why not?" and Thorny looked annoyed. "I've watched also, and he doesn't act like a deceitful boy. To-day I asked him if he wanted any money, or should I put what I owe him with the rest, and he looked me straight in the face with such honest, grateful eyes, I could not doubt him when he said: 'Keep it, please, I don't need anything here, you are all so good to me.'" "Now, Celia, don't you be soft-hearted. He's a sly little dog, and knows my eye is on him. When _I_ asked him what he saw in the dressing-room, after he brought out the ball, and looked sharply at him, he laughed, and said: 'Only a mouse,' as saucy as you please." "Do set the trap there, I heard the mouse nibbling last night, and it kept me awake. We must have a cat or we shall be overrun." "Well, shall I give Ben a good blowing up, or will you?" asked Thorny, scorning such poor prey as mice, and bound to prove that he was in the right. "I'll let you know what I have decided in the morning. Be kind to Ben, meantime, or I shall feel as if I had done you harm in letting you watch him."