"Thank you, Sam." Nancy's voice was unruffled as her fingers closed spasmodically over the paper concealed in the napkin. Seeing her friends were still occupied, she seized her chance, and whispered rapidly: "Go to Mr. Shriver's room at Wormley's, search behind the glass in the mirror over his bureau; then bring the paper you will find concealed there to me at the Perrys' to-night." Sam nodded understandingly. Nancy rose. "Senator Warren, will you help me on with my coat." CHAPTER VI THE SIGNAL LIGHT "Are you sure you have made no mistake, Lloyd?" whispered Colonel Baker in his companion's ear. "Positive, Colonel; I have laid my plans too carefully for that." The two men were crouching behind a corner of a tumbled-down stone wall. Their position commanded a full view of an old square mansion standing some little distance from B Street. The galleries on the south side of the house overlooked a low, rolling meadow which ran down to the Potomac River. "Have you no proof against the girl?" "No tangible proof so far, though I am morally certain she is the cleverest spy of them all." "Why not arrest her on suspicion?" "What good would that accomplish? Her family and friends are the most influential in the District. Without actual proof of her guilt, you could not hold her forty-eight hours." Colonel Baker moved restlessly. Such tactics were foreign to his nature. He believed in arresting first and investigating afterward. But his department had gone too far in a recent case, and he had been warned by no less a person than the President himself that his high-handed methods would no longer be tolerated. "My idea is to make her convict herself," resumed Lloyd, after a slight pause. "And you think your plot is going to work?" "It has succeeded so far. I found out that Colonel Mitchell was entertaining Senator and Mrs. Warren, and that Miss Newton was to be of the party. The colonel's sentiments for her have changed within the last few days. I shouldn't be surprised if she had snubbed him, and wounded his vanity. Anyway he was quite willing to enter into a little scheme I suggested. I put it on purely patriotic motives, mind you," Lloyd smiled grimly to himself, "that, as a loyal Union officer, it was his duty to assist me. So he wrote a bogus despatch, purporting to come from the adjutant-general, which he was to drop accidentally before Miss Newton, and then give her an opportunity to pick it up." "Did she do it?" "I am positive she did, although I did not actually see her. I saw Mitchell, who managed it very cleverly, drop the paper, and as they left their table I walked over to it. The paper had disappeared from the floor." "Why didn't you arrest her then?"