“Man overboard!”

The cry that never fails to thrill the heart of every sailor rang out on the deck of the submarine, as old Silas rightly interpreted the uproar on the battleship. Far above them boats were swung out and crews rushed into them. From the stern of the big fighting ship life belts and lines were tossed.

But long before any of the man-o’-war’s boats could touch the water, the submarine was headed about and rushed at full speed toward a tiny black object bobbing on the water far astern of the cumbrous battleship.

That object, looking no bigger than a shoe button, was a man fighting for his life in the wake of the ship from which he had been lost. Mr. Dancer, in the steering section of the White Shark, had seen the accident reflected in the periscope. His mind was made up in an instant. Using the emergency appliances he had for handling the engines, he had brought the White Shark around in incredibly short time and had headed for the drowning man.

Up on deck Jack and Tom had their shoes and their coats off, ready to leap after the castaway if necessary. Mr. Chadwick had seized a life-saving buoy from its hook just inside the hatch and stood ready to hurl it. As for old Silas, he shouted:

“Hold on, mate! We’re comin’! Hold on!”

The sea was not in itself rough, but in the wake of the speeding battleship it was decidedly so. The White Shark rolled and plunged like an empty bottle as, at express speed, she cut through the boiling mass of foam and angry, choppy waves.

“He’s still afloat!” cried Tom, as the White Shark rose on the top of a wave and they saw the head of the swimmer they were going to save, if human aid could do it.

“And making a brave fight for his life, too,” cried Jack. “Fight on, old fellow, we’re coming.”

The man waved a hand as the White Shark ranged close to him. Before any of those on deck knew what he was going to do, Jack was overboard. In a few strong strokes he was alongside his man. The next minute they saw Jack clutched with the desperate grip of the drowning, and dragged under water.

“He’ll drown!” cried Tom despairingly, and the next instant he, too, was overboard and striking out for the spot where the two swimmers who had vanished had last been seen.

Suddenly they flashed to the surface, and Tom saw, to his huge delight, that Jack had broken the other’s grip and was now swimming with an unconscious burden.

“I had to almost knock his head off before he’d let go,” panted Jack, as Tom swam up.

“Where’s the White Shark? You can’t hold him up much longer.”

“Here she comes! Hurray!”

The submarine slowly ranged up to the group in the water, and Mr. Chadwick threw the life belt. Tom caught it and the two boys thrust it over the unconscious man’s head. Then, while they swam alongside, holding on to the belt, Mr. Chadwick and Silas hauled in on the line attached to it. In this way they reached the side of the submarine and were pulled on deck almost exhausted.

They had hardly reached safety when Mr. Chadwick gave a cry of alarm.

“Look!” he shouted, “look!”

Coming right at them was something they had quite forgotten. The second battleship in the long column of sea fighters!

She was close enough to them to make her bow look like a steel cliff. They could almost hear the roar of her cutwater as it cleaved its way through the sea.

“Come below instantly! Close the panel! It’s our only chance!”

The voice was Mr. Dancer’s. It came from the mouth of the speaking tube situated in the hatch for purposes of communicating with the deck from below.

Without stopping to take another look at the huge menace bearing down upon them, the boys, assisted by Silas, picked up the unconscious form of the man they had rescued and carried him below. All this was done with lightning speed. Anxiety, cold panic, made them move like those who dream, but still with promptitude.

As the metal door clanged to Jack shuddered; it sounded almost as if the steel bow of the battleship was cutting into them at the moment, cleaving them in two and sending the White Shark and her crew to an unmarked grave in the bed of the ocean.

The diving boat gave a sickening plunge the next instant. It seemed as if she were making an almost perpendicular dive to the depths. Those in the cabin who had rushed from the deck in the nick of time were thrown in a bruised mass at one end of the main cabin. As for Jupe, only a wild yell proceeded from his regions. He had no idea of what was happening.

It appeared to him that the White Shark was taking her last plunge. It seemed that way to the others, too. Huddled together, they turned white, questioning faces on each other. Not even the unconscious man was more deadly pale.

Nobody spoke, but each knew without resorting to words, of what the other was thinking.

Had the dive come too late to carry the White Shark safely under the keel of the battleship driving down upon them?

Suddenly there came a grating, grinding shock that seemed to shake the White Shark to the last rivet of her fabric.

“Great heaven! They’ve struck us!” cried Silas in a terrible voice.

“We’re going to the bottom!” shouted Tom beside himself with terror.

The submarine hesitated for an instant, and then turned slowly on one side.

“It’s the end!” cried Mr. Chadwick.