ain of a man, but his
voice broke off as the commotion started again. Certainly he must have a
rough customer to deal with, thought Jerry, if he, with all his great
physical strength, could not entirely quell him.

"Ye will, will ye?" hissed the voice of the engineer again. "Thry to
bite me, eh?" and there was the terrible smash of a fist, and the
unmistakable sound of a man falling upon the deck. "Ye dirty hound, I've
a mind to boot ye into the sea."

And then there were other voices. Jerry heard the captain demanding an
explanation, and the ship's doctor spoke.

"I found him tamperin' with the wires near the dynamos," the first
assistant engineer was saying. "I niver liked his looks annyway, if
ye'll pardon me, sir, fer sayin' it. And whin I asked him what he was
about, he thried to git away. I grabbed him, and he showed fight. I
guess I give 'im all he wanted, though, that last time."

"So?" said the captain, in a voice so stern it made Joe wince. "And what
does this fellow do aboard the ship?"

"He's a third-class machinist, sir," the engineer replied. "But if ye'll
excuse a word from me, sir, I think he's a first-class crook."

"Yes, and I believe he's worse than that," the captain added; and then,
in a voice which seemed to shake the vessel: "Stand up!"

There was a strained silence for a moment. Then--

"Get Lieutenant Mackinson and those boys," the captain continued, and
the ship's surgeon started down the stairway to find that Joe and Jerry
already were summoning Slim and the lieutenant.

"It looks as though we'd caught the man," the doctor whispered.

As the four reached the deck where the captured man stood between the
first assistant engineer and the captain, who had by this time taken out
his revolver, there was a gasp of astonishment from Joe, followed by a
louder "Holy smoke!" from Slim.

"Do you recognize this man?" the captain asked in a sharp tone.

"I should say I do, sir," Joe responded. "_He is the man who was
planting ammunition in the waters near the navy yard that night before
we sailed_!"

"The very same one, sir!" Slim exclaimed, with equal positiveness.

The ship's surgeon, who had followed the others upon deck, stepped
closer for a better inspection of this enemy. At the same instant the
prisoner, striking out with both hands, knocked the captain's revolver
hand into the air, and thrust the engineer from him. Before anyone could
interfere he was dashing down the deck toward th