“We’ll take no chances,” decided Jerry. “As soon as he recovers fully we’ll take him below.”

But this was never destined to be done.

Dr. Klauss suddenly leaped to his feet, and rushed to the edge of the deck. Raising his hands high above his head he cried out:

“I defy you all!” And then, before anyone could prevent him, plunged overboard.

“Poor fellow!” cried Mr. Sheldon. “We must save him!”

But there was no way. No small boat was available, and it would have been folly for anyone to have jumped into the sea to try to save a maniac.

But Dr. Klauss had no intention of ending his life, it seemed. He disappeared under water for a few seconds, and then was seen to be swimming for the island.

They watched him make his perilous way through the surf to the beach. He seemed strong, even after his trying experience.

Reaching shore, the madman stood up, and shook his fist at those on the deck of the submarine. Then the unfortunate man rushed into the dense growth that came down close to the water’s edge.

And that was the end of Dr. Klauss. The boys and their friends never saw him again.