Something wrong with the hoist! Johnny experienced a cold chill. Suppose someone had been tampering with that hoist—had done something really serious? What then? You couldn’t take hold of a fifteen-hundred-foot steel cable with a two-ton ball at the end of it, and haul it by hand like a fishline. Johnny realized all too keenly that his life depended on that hoist.

“It could have been tampered with,” he told himself. This was all too true. While the boat had been in the harbor it had not been any too carefully guarded—and Johnny had been off duty one whole night! “Might cost me dearly—that night!” he thought.

To ease his mind he began watching the passing show—fire-glowing shrimps—flying snails, and a host of other strange creatures. He snapped his camera again and again.

“I say, up there,” he exclaimed impatiently, “what’s keeping us?”

“Sorry, Johnny. It’s the hoist. We—”

Doris stopped suddenly. Johnny felt a shock—as if his cable had been struck by something hard and heavy. At the same instant the ball began drifting away from the submerged wall of rock.

“Hey, there!” he called, in genuine alarm, “what’s up now?”

There came no answer. He called again, and yet again. No answer. His heart began pounding madly.

“This won’t do,” he told himself, savagely. “Probably nothing—just nothing at all! It—”

Then came a second, jolting shock, and—ceasing to move in a circle—the ball began drifting quite rapidly away from the rock and out to sea.