"Look!" cried Mary, as she went through the rooms with Bob. "There is a handkerchief. She snatched it up. It was one of her own, with the initials "M. B." in a monogram. "Lorna has been here," she exclaimed. "I remember handing her that very handkerchief when we were in the store yesterday." "What's to be done now?" thought Bobbie. "We had better go up to your father and tell him what we know--it is not as bad as it might have been." "Precious little comfort," sighed Mary, exhausted beyond tears. They reached the desolate home, and Bob broke the news to the old man. As Mary poured forth her story of the discovery in Trubus' office, her father's face lighted with renewed hope. To their surprise he laughed, softly, and then spoke: "Mary, my child, my long hours of study and labor on my own invention have not been in vain. My dictagraph-recorder--this very model here, which I have just completed shall be put to its first great test to save my own daughter. Heaven could reward me in no more wonderful manner than to let it help in the rescue of little Lorna--why did I not think of it sooner?" "What shall we do, father?" breathlessly cried Mary. "Can I help, Mr. Barton?" "Describe the arrangement of the offices." Mary rapidly limned the plan of the headquarters of the Purity League. Her father nodded and his lips moved as he repeated her words in a whisper. "I have it now. You must put the instrument under the telephone switchboard table," he directed. "Pile up a waste-basket, or something that is handy to keep it out of view. I have already adjusted enough fresh cylinders to record at least one hour of conversation. This machine is run by an automatic spring, which you must wind like a clock. Here I will wind it myself to have all in readiness." He rolled his chair swiftly to his work table, and turned the little crank, continuing his plan of attack. "Now, take the long wire, and run it through the door of the private office up close to the desk. Attach this disc to the dictagraph receiver. It is so small, and the wiring so fine that it will not be noticed if it is done correctly. Here, Burke. I will do it now to this loose dictagraph receiver. Watch me." The old man worked swiftly. Burke scrutinized each move, and nodded in understanding. "Be careful to cover the wire along the floor with a rug--he must never be allowed to see that, you know. After you have all this prepared, Mary, you must start the mechanism going, and then get the reproduction of the conversation as it comes on the dictagraph." "All right, father--but how shall we get it there without Mr. Trubus knowing about it? He is very watchful of that room." Barton patted Bobbie's broad shoulder, with a confident smile.