With some difficulty Pariset squeezed his body between two of the floats, hoisted himself up, and stood in the interior of the wheel. The rotten woodwork creaked, and the wheel itself groaned slightly as it moved an inch or two; but the movement was checked by the rusty chains. Kenneth followed more easily. They swung themselves on to the axle, jerked their way along it, came to the hole of which the miller had spoken, and clambering up through it, stood on the floor of the toolroom. Hands and clothes were coated with red rust. The room was lit by a small window overlooking the stream. To their surprise, it was not empty except for a few rusty implements, as they had expected from the miller’s description. A new deal bench stood against the wall, flanked by a turning lathe, and an elaborate engineering equipment. "Electrical!" Pariset whispered. Treading very carefully, they gently opened the door, took a look round, and passed into the capacious storeroom. Here they found the plant of a wireless telegraphy installation. The antennae passed through holes in the ceiling, emerging, as they guessed, under cover of the parapet, on the flat roof of the mill. In the fast-fading light they were just able to see a doorway on the right, leading, as they knew from the miller’s description, to the hoist and shoot. In front of them was another door, now open, giving access to a passage between the kitchen and the dining-room. Pariset slipped off his wet boots. "Wait here," he whispered. Stealing along the passage, he came to a door on the right. He put his ear against it, and heard the clink of knives and forks mingled with guttural conversation. Creeping back again, he whispered: "They are feeding. Come along!" They passed from the storeroom into the chamber which had formerly contained the hoist. Here they noticed a tall heap of earth. "They dug that out when continuing the underground passage to the bridge," said Pariset. "Here’s the trap-door," returned Kenneth. "Look! There’s a wire running through it, connecting with the room behind." "It’s all very thorough, confound them!" said Pariset. "I hope the trap-door won’t creak." They lifted it gently, and found that it moved on a central axis, well oiled. Peering into the dark depths, Kenneth discovered a wooden ladder. They crept down this, into a large underground chamber flagged with stone, and ventilated by narrow gratings in the brick walls, above the level of the stream. "We had better not both go on," said Pariset. "I’ll go up and keep watch. You proceed, and cut the wires at the further end of the passage." "Why not here?" said Kenneth. "It would save time." "But if the word should come to fire the mine, and they find the apparatus doesn’t work, they’d soon discover the cut here and repair it. Much better do the damage at the other end." "Very well. You’ll use your revolver if they come before I get back?"