The submarine rocked, dipped, and seemed about to sink. The helm of the destroyer was changed instantly and she shot straight for her quarry.

"She'll sink her! She's going down!" yelled Al Torrance, clinging to a stay beside Whistler, as the cutter bobbed through the rather choppy seas.

But the Germans had no desire for a glorious death. Up went the white flag, and the men on her deck put up their hands, signifying that they had surrendered. Probably they were already crying "_Kamerad!_"

The destroyer did not even drop a boat to send aboard a crew. She steamed right up beside the submarine, put out a ladder for her captain, and then sent a hawser aboard for the German crew to fasten. She would tow her prize to port without risking any of her own crew aboard the wabbly undersea boat.

When the cutter drew near, her ship's company cheered and jeered the bluejackets on the destroyer with good-natured enthusiasm. The destroyer was then steaming away with the U-boat in tow.

"Something's fouled your patent log!" yelled one seaman aboard the cutter.

"Hey, there, garby!" shouted another. "What's that the cat brought in?"

The crew of the destroyer, evidently mightily swelled with pride, refused to reply to these scoffing remarks.

As long as the twilight held the cutter steamed into the east and south. By dark the destroyer and her tow were out of sight. The cutter began to burn occasional lights. Then the wireless chattered again.

"Hurrah, boys!" whispered Whistler to his three mates. "I believe the _Kennebunk_ is near."

Nor was he mistaken in this supposition. The night was dark, the stars were overcast, merely a fitful light played upon the surface of the sea.

The horizon ahead was quite indistinguishable from the water itself. But at last a faint glowing point appeared upon it. Ensign MacMasters and the commander of the cutter showed excitement as they watched this spot through their night gla.s.ses.

"Is it a star?" asked Frenchy.

"A star your grandmother!" snorted Torry. "That's a ship."

"A big steamship under forced draft," added Whistler. "And I believe it is the _Kennebunk_."

It was the glow above her smokestacks that they saw. Within half an hour the fact that a huge steam craft was storming across the cutter's course could not be doubted.

Mr. MacMasters gave some sharp orders to his men. The latter had nothing with them but the water-shrunk garments they stood in; so it took but a moment for Mr. Mudge to line them up properly along the rail.

The great battleship began to slow down when the cutter was at least three miles from her. Otherwise she would have pa.s.sed, and the revenue craft would have been a long time catching up.

The cutter was run in to the side of the towering hull of the superdreadnaught. The port ladder was down. A number of the watch on deck were strung along the rail, and the officers did not forbid their cheering the members of the wrecked tender's crew.

"Welcome home again, Mr. MacMasters!" was the greeting of the officer of the watch as the ensign led his party up the ladder.

"And mighty glad we are to get here," declared Ensign MacMasters.

The boys and men scrambled aboard and bade good-bye cheerfully though gratefully to the cutter's crew. The latter craft turned on her heel and shot away toward the distant coast.

Already the huge battleship was under way again. She was running with few lights. And where she was running was a question that even the members of the crew the boys put the question to could not answer.

It was generally known that Captain Trevor had received orders by wireless that had changed the plan of the cruise entirely. Instead of running back up the Atlantic coast, they had put to sea.

It was the next day before the _Kennebunk's_ company in general knew that she was bound first for the Azores. That meant a European cruise, without a doubt. All the "old timers" were agreed upon that.

It was finally rumored about the ship that the report of the _Kennebunk's_ cruise to the southward, and the score of her gun crews at target practice, together with her good luck in sinking a German submarine with the first shot ever fired from her guns, had so impressed the Department that she was to join the European squadron under Admiral Sims at once.

"There's a chance for you boys to see some real action," declared one of the masters-at-arms. "If the Hun comes out of Kiel, we'll be there to say 'How-do!' to him."

The boys who had been absent from the battleship for so long found, however, that the spiritual atmosphere of the crew was not much changed.

There were still a lot of "croakers" as Torry called them.

"They are ghost-ridden, as sure as you're born, Whistler," Torry declared. "Somebody has heard that clock ticking again. It doesn't seem to be at work all the time. Just now and then. 'The death watch' they call it."

"Stop it!" ordered Whistler. "The less said the soonest mended about such things aboard ship. We boys don't believe such foolishness, do we?"

"How about the old witch's prophecy?" asked Torry wickedly. "Suppose we should tell these garbies about them?"

"Don't you dare!" cried Whistler.

That very morning, after sick call, he was ordered to appear before Captain Trevor in the commander's office, and there found a.s.sembled Ensign MacMasters and several of the other officers of the ship with the commander.

"Morgan," said Captain Trevor, "let me hear about your finding of this paper Mr. MacMasters has brought to our attention. There seems to be something of moment in it in reference to the _Kennebunk_."

Ensign MacMasters put a translation of the torn letter into the young fellow's hand. The letter had been so mutilated that it was impossible; to make any exact translation of it. But here were extracts that stood out plainly:

"_. . . success of your water-wheel bomb.

Congratulations._

"_. . . from Headquarters an order to_ . . .

"_. . . If it equals your former . . ._

"_. . . clockwork arrangement that may raise your name as an inventor to the nth power. The Ken---- . . ._

"_. . . shall hear of her destruction at the time appointed._

"_. . . for the German Fatherland._"

"I am told that you, Morgan, have some knowledge of the dastardly work of this spy, Franz Linder. Is it so?" asked Captain Trevor suggestively.

"Oh, sir!" cried the young fellow, in excitement, "I believe I know what is referred to here by Linder's correspondent, as 'the water-wheel bomb.' That is what he blew up the Elmvale dam with!"

"Do you think, from what the woman on the island said, that there is some plot afoot against the _Kennebunk_?" went on the commander.

"It's referred to right here!" declared the excited Whistler. "This 'clockwork' thing. Oh, Mr. MacMasters!" he added, turning abruptly to the ensign. "You know some of the crew, before we left to carry poor Grant to the hospital, were bothering about a sound they had heard on the lower deck? Remember Seven Knott's ghost?"

"Right!" declared the ensign. "I had forgotten it, Captain Trevor," he added. "Something about a clock ticking."

"I have heard it myself," Whistler said eagerly. "And the boys say they have been hearing it, off and on, while we were gone."

"Do you two mean to intimate that there is a time bomb, or some such infernal machine, aboard this ship?" demanded Captain Trevor, in contemptuous amazement.

"Look at this, sir," urged Whistler so earnestly that he forgot his station. "'_. . . clockwork arrangement that may raise your name as an inventor to the nth power._' That certainly means something. And that noise below does sound something like a clock."