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.

There came suddenly a faint buzzing from the interior that startled
everybody near. Then followed the ticking sound, which lasted at least a
full minute.

The warrant officer jerked away a layer of pasteboard that hid what was
under the tray. Several grim cylinders lay side by side in the chest's
bottom. They were connected by wires with a mechanism that hummed like
the purring of a well-piled motor.

"Clockwork!" exclaimed the carpenter's mate, bending over the chest.
"That's what she is. Ah! It reverses itself. See that spring--winding
tighter and tighter? Why, it's almost perpetual motion! Some inventor
that fellow!"

"What fellow?" growled the warrant officer.

"Whoever built this."

"Can you stop it without exploding those cylinders?"

"Great Scott! Do you s'pose that's dynamite under there?"

"Or T N T."

The petty officer thrust an iron bar suddenly into the heart of the
complicated machine. Something snapped. The mechanism stopped.

"Great heavens, man!" gasped the warrant officer, "suppose you had set
it off?"

"No. Couldn't be done till the spring here was wound up to the
top-notch. This machine was arranged to run for weeks. Some ingenious
arrangement, take it from me!"

The discovery and destruction of the