"Yes, Mary; tell Miss Agnes I shall be in all the rest of the afternoon, and that I shall be at her disposal at any time." Sturgis, picking up his hat and coat, hurried from the house. "Why did he want to shut me in the extension?" he asked himself over and over, and he could find no satisfactory answer to the question. Then he took from his pocket the lines he had written on Murdock's typewriter, and compared them carefully with those on the sheet which he had laboriously pieced together in the Knickerbocker bank on the previous day. The result of the examination was apparently satisfactory; for, when Sturgis returned the papers to his pocket, his face wore an expression of calm but unmistakable triumph. CHAPTER XIX. THE UNDERGROUND PASSAGE. As he reached the corner, Sturgis came upon Sprague, who was waiting for a car. "Oh! I say, old man," exclaimed the artist, hardly able to conceal his elation, "I am glad to see you. I have news to tell you." "So have I. But I am in a hurry now. Come along with me; we can exchange confidences on the way." "Very well; whither are you bound?" "I am on the track of big game. Can you spare a couple of hours? I think I can promise you an interesting afternoon." "What is it? The Knickerbocker bank case?" "Yes." Sprague readily consented to accompany his friend. "By the way," inquired Sturgis, "have you any weapons?" "Any quantity of them among the properties of the studio," replied Sprague surprised; "but I do not go about armed in broad daylight." "You would better have a revolver," said the reporter. "You will probably have no occasion to use it," he added in answer to his friend's glance, "but it is best to be on the safe side." "Very well; I shall go home for one. Where am I to meet you?" "At police headquarters in about half an hour. Let me see; it is now nearly five o'clock. Say at half-past five. It will be necessary to obtain a couple of warrants and the help of the police before we start." After Sprague had left him, Sturgis approached Detective Conklin, who was still at his post. "Has Chatham shown up while I was in there?" he asked, indicating Murdock's house. "No, sir." "Did you notice the man with whom I went in?" "Yes, sir." "Well, let Chatham go for the present and stick close to that man if he stirs from the house. I shall be back in less than an hour." "All right, sir." When Sprague reached police headquarters, he found the reporter ready to start with four detectives. He had not, therefore, any opportunity for conversation with his friend until the party reached its destination. There two of the detectives relieved the men previously on duty, while the others accompanied Sturgis and Sprague to the office of the Manhattan Chemical Company.