. He pitched and fell
forward.

With a snarl of glee Gaston burled himself upon the prostrate body of
the second submarine boy, pounding him furiously.

CHAPTER XIII

THE FELLOW WHO SHOWED THE WHITE FLAG

Hal lay face down, and subjected to all the brutal fury of the
Frenchman's assault.

For a few seconds young Hastings did all in his power to fight back.
He was rapidly losing consciousness, however, and poor Jack lay unable
to lend as much as a finger's weight to the defense of his chum.

Then, with an oath in a foreign tongue, Gaston forced Hal's hands back,
snapping handcuffs on the engineer's wrists.

"Now, then, you young pest!" snarled Gaston, springing to his feet.
"Instead of one of you, I have two. But two shall give me no more
trouble than one. So you thought you could subdue me--_me_, did you?"

"I'd have thrashed you all right," muttered Hal, his senses returning
under the storm of taunts, "if my foot hadn't caught and thrown me.
You wouldn't dare to free my hands and let me to my feet, just to see
what would happen to you! You can't fight--unless all the advantage
is handed to you. You're a coward--not a fighter!"

"Careful, my young firebrand, or I'll teach you to be more polite to
me," sneered the Frenchman.

"Polite to you?" jeered Hal. "Polite to a spy--to a thief of nations!
Polite to a scoundrel who wants to steal the biggest secret of defense
that the United States Navy has!"

"Oh, we'll have your secret all right," announced the Frenchman, his
voice harsh with triumph. "We now have the two boys who know all about
the secrets of the Pollard boats!"

"This sounds so good, I reckon we'd better go right on in, Jerry," broke
in another voice.

Gaston started, as did the two submarine boys. Then the chauffeur
leaped to the mouth of the tunnel, only to draw back in dismay as a
big form emerged and loomed up before his startled vision.

The last comer wore the dress and insignia of a petty officer of the
United States Navy.

"Get back there!" warned this big apparition, waving a warning hand that
looked big enough to be a ham. "Nobody can't go out until we look into
this cargo."

After the big sailor a smaller one crawled out of the tunnel, rising
to his feet. Though he was smaller, this second sailor was not exactly
what could have been called a little man.

"Now, then," demanded the big sailor, "whose captain of this craft?"

Gaston, his eyes threatening to bulge