With the interruption, however, his hand closed quickly on the wooden lever, which moved like a flash to one side under the swift action of his powerful arm. Instantly a section of the floor under the detective’s chair fell straight downward, swinging on hinges like a trapdoor. It was like having the earth itself drop from under him. Coming without the slightest warning, finding him utterly unprepared for such a trick, Nick had neither time nor means by which to collect himself, or to avoid the inevitable fall. Like a flash, together with the chair on which he was seated, Nick vanished through the floor and sped downward through empty space. The trapdoor swung upward like a pendulum, and Ardley, venting a roar of mingled triumph and derision, jerked it back in its former position and secured it with the lever. CHAPTER VII. THE GANG AND THE GAME. Nick Carter did not fall far, yet far enough to jar him from head to foot and smash to fragments the chair on which he was seated. Nick landed in about a foot of water, moreover, drenching him to the skin, yet the chill of which served instantly to revive him. He found himself in almost total darkness. The only light came through a chink a foot or more above his head. It served to reveal four bare, wet walls of planking, however, also the floor through which he had been precipitated, with the trapdoor now grimly closed. Nick had heard the crash of it when Ardley closed and secured it, also the mocking roar of the monstrous rascal, and it took Nick only a moment to determine in what sort of a trap he was confined. He could hear the gurgling of the water in the mill sluice, separated from him by one of the plank walls, and he knew that the rocky ground under his feet must be on a level with the bottom of the sluice. “By Jove, that was a quick and unexpected trick,” he muttered, after scrambling up from the water swirling around him. “I’m in a section of the sluiceway that has been boarded in to reduce the flow of water to the wheel. If this rascal opens the gate that admits the water from the river--well, I shall be drowned like a rat in a trap. “Did he have that infernal contrivance constructed for such emergency as that in which I placed him? This looks very much like it. I have in Chick, however, an anchor to the windward. If I can stave off a more devilish move by this scoundrel, it’s long odds that Chick will show up in time to take a hand in the game.” It was not in Nick’s nature to hurry to meet trouble halfway. He preferred to combat it only when it overtook him. A brief examination of the four walls in which he was confined, and which inclosed a space about eight feet square, convinced him that immediate escape was utterly impossible. Listening, he could hear Ardley’s tread on the floor, but not a sound yet had come from the scoundrel, though several minutes had passed since he closed and secured the trap.