“_. . . 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.”

“It seems ridiculous,” stated the commander of the Kennebunk.  “And yet we must not refuse to believe that the secret agents of Germany are at work in the most impossible places.  If they could sink this great, new vessel in mid-ocean!  Mr. Smith,” to his first lieutenant, “have that part of the ship searched.  Find out what causes the sound which has been heard before you make your report.  We’ll investigate this matter to the very bottom.”

CHAPTER XXIV

TICK-TOCK!  TICK-TOCK!

The superdreadnaught was so huge a ship, and the divisions of the crew were so busily engaged in drills and other work, that few, indeed, knew that the “ghost of the Kennebunk” was being investigated by the officers.

The ship was storming along her course through the sea at a pace which fairly made her structure shake.  Had one been able to be out upon the sea on another ship and watch her pass, her speed would have been impressive, indeed.