“Can't help it, Mallory. When that man reports to his employer, I want him to say that we suspect nothing beyond his attempt to crack the safe.” The detective turned away with a frown. “I suppose you know your business, Mr. West.” Harvey and Mattison followed him to the hall, closing the door after them. They said good night, and left the building. “See here, West,” said Mattison, when they were fairly around the corner, “wasn't that a little hasty? It wouldn't hurt to keep the man out of the way.” “No, I don't agree with you. What McNally has done so far will be upheld by his judge. And another thing, Mattison; just at present, it isn't to our interest to get an investigation under way. We're going to do the same thing ourselves.” Slowly and cautiously they slipped around the next square, and, by returning through the alley, brought up in the shadow of a building, across the street from the train shed. Here they waited to reconnoitre. The night was clear, and the arc-lamp at the corner threw an intermittent glare down the street. As they looked, a long shadow appeared on the sidewalk. Mattison gripped Harvey's arm, and drew him back into the alley. They crouched behind a pile of boxes. “It's like stealing apples,” whispered Harvey. “When the old man gets after you with a stick.” “Ssh!” The footsteps sounded loud on the stone walk. Then a helmeted figure passed the alley, and went on its way. Waiting until the sound died in the distance, the two stepped to the walk, looked hastily toward each corner, and ran across the street. Once in the station alley, they paused again. “Look!” said Harvey, pointing; “he left the ladder.” Sure enough, a light ladder reached from the ground nearly to a second-story window, which stood open. “Well, here we are,” Mattison whispered. “How do you feel?” “First-class. Better let me go,--I know the combination.” Mattison stood at the foot of the ladder, and steadied it while Harvey stealthily climbed to the window. Drawing himself into the passage, the receiver set to work on the vault lock. He turned the knob very slowly, guarding against the slightest noise, but the faint light that came through the window was not enough to bring out the numbers. Harvey leaned back and considered. The scratching of a match would almost surely be heard by the detectives. He leaned out the window, and beckoned. Mattison came creeping up, and Harvey explained in a few whispered sentences. “Go back and look up the street,” he concluded. “We've got to light it outside the building.” While Mattison was gone, Harvey felt his way through the Treasurer's office and paused to listen; then he drew up a chair which stood near the door, and climbing up, slipped off his coat and hung it over the half-open transom. Then he closed the transom, and the room was practically light proof. With the same caution he reached the floor, and tiptoed back to the window, where he found Mattison waiting on the ladder.