“Predictions beyond that point would be speculative. I will make only one. If Cady proves to be the man of nerve and courage ascribed to him by President Burdick—well, in that case, Chick, if this bunch of bandits gets away with the money, I’ll chuck my vocation and open an old man’s home.” Chick Carter laughed. CHAPTER IV. THE REAL SUBSTITUTE. It was a clear night with a myriad of stars in the sky. The silver crescent of a quarter moon had sunk below the wooded hills in the west. A chill from the distant mountains was in the air, though but little wind was stirring. The midnight stillness of the rural country south of North Dayton, where the lofty signal tower loomed up at the junction of the western division of the S. & O. Railway, was broken only by the frequent croakings of frogs in a swamp east of the tracks, or the occasional cry of some night bird circling overhead. The N. D. tower, as it was known on the wire, was in a lonely locality. Trains stopped there only for water, or in response to the signal lights, which changed from green and red to white when the night operator, Tom Denny, worked the huge levers in the tower chamber. He was seated at his telegraph stand shortly before twelve on that eventful night, a compact, muscular man of middle age. A revolver was lying near the instrument. The murder in the K. C. tower at Shelby, the brutal killing of Karl Glidden, also the other crimes and the outrages along the S. & O. road—all were so fresh in the mind of every night operator during his weary vigil, that none was taking any chances of being caught unprepared. Three bells suddenly broke the stillness of the tower chamber. They told Denny that the operator in the next tower north was waiting for his unlock, that the Southern Limited was approaching North Dayton, and Denny pushed the plug into the box and held it for an O. K. Getting it almost instantly, he arose and set his signals. As he turned from the lever, he heard a step on the tower stairs. As quick as a flash, while a hand was laid on the knob of the door, Denny stepped to the table and seized his revolver. The door was opened and a roughly clad, bearded man appeared on the threshold. He looked like a track hand, or one employed on the railway. He was a stranger to Denny, however, who covered him instantly, crying sharply: “Hold on! Stop right there! What do you want?” Nick Carter smiled and said quietly: “A few words with you, Denny, nothing more. I have a letter of introduction from President Burdick. It will tell you who I am and why I am here.” Denny appeared incredulous and suspicious. “Stay where you are!” he commanded. “Toss me the letter, then hands up while I read it.” Nick obeyed, remarking, with a laugh: “You’re all right, Denny. He will be a good man, indeed, who catches you napping.”