“That small cable runs right along overhead,” declared Ned, holding up the lantern to better illuminate the roof. “I’m blessed if I can see what’s holding it up there!” he continued. “It must be—”
The words were cut short by a warning shout from Dick, and turning, Ned caught the reflected gleam from the surface of a black pool which filled the tunnel from wall to wall.
“Jump for it!” yelled Ned, and in an instant both boys had leaped from the rear of the car knee-deep into the icy water.
Floundering back up the passage, they gained dry ground, and straining their eyes through the gloom, watched the car as it continued on its way down the track and disappeared beneath the inky water.
“Wow! We came near getting an all-over ducking!” cried Dick, as he stooped to wring the water from the bottom of his trousers.
“It was mighty stupid of me not to have been looking out for this,” Ned blamed himself. “Of course everybody knows the tunnel runs out under the lake and that the lower end is full of water.”
“The car is still going ahead,” announced Dick. “Look! The cable is running out yet.” But even as he spoke, the black wire rope dragging along between the rails suddenly stopped. “She’s got to the end of the tunnel,” he continued. “Now what!”
For a moment Ned Blake did not reply. He was staring up at the line of small cable stretched tightly along the roof of the mine and passing from sight where roof and water-surface met.
“I know what’s pulling so hard on that rope,” he said quietly. “It’s that buoy.”
“By jiminy! You’re right!” Dick’s voice rose excitedly. “And when that small winch is released, the buoy rises to the surface of the lake! But—but what’s the use of all this? That’s what I can’t make out!”