The rumble of machinery was louder and came from directly beneath his feet. Also he could hear a muffled murmur of voices. He had not been mistaken. The workroom was immediately beneath. Joe reached the bottom of the ladder in silence. Frank groped for the flashlight. He switched it on. The room in which they were standing was a low-ceilinged, bare chamber, on the far side of which was a doorway that led to a flight of stairs. Frank stepped cautiously over to the door and peered down the stairs. They led to a landing a short distance below, and continued from there to the bottom of the mill. The room beneath the one in which they were standing evidently opened onto the landing. Frank made a mental note of all these features so that he would have a good idea of the layout of the building in case it became necessary for them to make a hurried retreat. He heard a whisper from behind him. He turned quickly. Joe was crouching on the floor, peering through a crack in the boards. He motioned to Frank to come over. CHAPTER XXIII THE ALARM Frank crouched on the floor beside his brother. He switched off the flashlight. The room was in darkness. Immediately he could see a glow of light through one of the cracks in the flooring. By crouching close to the floor he could see through the cracks into the room beneath. At the sight he saw he almost gave an exclamation of triumph. There were three men in the room, the three men of the mill--Uncle Dock, his companion, and Markel. They were standing beside a machine that looked like a small printing press. Their sleeves were rolled up and they were wearing inky aprons. The printing press was rumbling steadily and Markel was feeding it with small sheets of peculiar greenish paper. But it was what was heaped on a low table beside the press that particularly attracted the attention of the Hardy boys. There they saw neat bundles of crisp, new bills. They were heaped high on the low table, each bundle in a thin, paper wrapper, and their denominations ranged from five to fifty dollars. "They're printing counterfeit money!" whispered Frank. Joe nodded. A tingling excitement possessed them. In spite of the fact that they knew the bills were counterfeit there was something fascinating in the sight of those hundreds of crisp, green bills. Their view of the room was limited, but by moving from side to side they were gradually able to take in all the details of the little chamber. Above the constant rumble of the press they could hear the voices of three men. "Once we get this shipment sent out we'll be on easy street," said Uncle Dock. "If we can get it all placed," grumbled Markel. "We'll get it placed all right," said the other man. "We haven't had any trouble so far. Burgess and his crowd have put over their part of the deal pretty well."