Routine work went on, and the bulk of the ship’s company knew nothing about that little party of searchers at work deep down in the ship.  Whistler was one of those assigned to find the cause of the “tick-tock” noise, and it was he who finally suggested the spot where the mechanism which caused the sound might be found.

The party had searched the lumber room and the compartments on both sides, that above, and the one directly beneath the room in question.  Nothing was discovered save that the sound seemed clearer in the lumber room than elsewhere.

Overhauling the stuff stowed there did no good.  They seemed no nearer to the sound.  And as the latter was not continuous it was the more puzzling.

“Don’t you think we ought to open that chest, sir?” asked Whistler of the warrant officer who had immediate charge of the work.

“It doesn’t seem to come from that box,” objected the man.

“It doesn’t seem to come from anywhere exactly,” Whistler said.  “It is sort of ventriloquial.  One time it seems to be from one direction, then from another.  But that chest hasn’t been open——­”

“Whose is it?”

“I don’t know, sir.”

“Who does know?” the warrant officer asked.

But nobody seemed able to answer that query.  The searchers gathered about the chest that had been pulled out of the heap of rubbish.  It was ironbound and made of heavy planking.

“It gets me!” murmured the officer.

Just then the sound started again:  “Tick-tock!  Tick-tock!  Tick-tock!”

“It don’t come from that box!” declared one man.

Whistler stooped and put his hand on the cover.  “Wait!” he said suddenly.  “Just feel this, sir.”

“What do you feel?”

“There is vibration here.  And it isn’t the vibration of the ship’s engines, either.”

The warrant officer rested his hand upon the chest.  He looked more puzzled than ever.

“Get something and break the lock!” he commanded.

“Wait a minute, sir!” cried Whistler.  “If there should be some infernal machine in that box we must take care in opening it.  Maybe the carpenter can pick the lock.”

“Good idea,” agreed the officer.

The carpenter’s mate was sent for.  He came with a bunch of spare keys and a pick-lock.  The latter had to be used skilfully before the lock of the chest was sprung.

Then the warrant officer suddenly experienced an accession of caution.  He refused to have the cover of the chest lifted until the chest itself was carried carefully out upon the open deck.

No sound came from the chest now, if that had been the locality of the tick-tock noise.  The vibration could be felt just the same.

The men were ordered to stand back and the warrant officer courageously lifted the lid of the chest.  Nothing happened.

There was an empty tray in the top of the odd chest.  That, too, was cautiously lifted out.