“Let go, you young hound!” ordered Millard, striking out savagely.

Jack hung desperately.  Yet the trouble was that the young submarine skipper had tackled a man who was at least fifty per cent. stronger and fully as agile.

While Hal still hung back, Millard gave a heave, then rolled himself over on top of Jack Benson.

“I’ll give you just a short lesson!” snarled the long-legged one.

He raised a fist, intent on bringing it down like a sledge-hammer across Benson’s face.

That blow, however, wasn’t the one that landed.  Biff! whack!  Two sturdy, hard fists registered on Millard’s head from behind.  Then a boy shot himself forward, battering-ram fashion, hurling Millard over to the ground.  The boy went with the fellow, landing on top of him.

And that boy was Eph Somers!

“Come on, Jack, if you want some of this!” offered Eph, generously.

Truth to tell, there was need of both the submarine boys, for Millard now fought more fiendishly than before.

Millard was a powerful fellow, when aroused, but he had pitted against him two of the doughtiest, gamest boys to be found along the Atlantic coast.  He was pretty well beaten up, in fact, by the time that Hal came limply upon the scene.

“Want any help?” demanded Hal, in a still somewhat breathless voice.

“Nope!” answered Eph, sturdily.  “Not unless you want exercise.”

As Somers spoke he landed another blow, this against the “wind” at Millard’s belt-line.  In the same instant Jack Benson managed to knot his hands in the fellow’s coat lapels, and to press the backs of his hands against the wretch’s throat.

“I sur—­ug-g-gh!—­er—­render,” gurgled the long-legged one, weakly.

“You’d better, unless you want to discover that we haven’t yet started in with rough handling,” retorted Eph valiantly.

Young Benson eased his hold on Millard’s wind-pipe.  Yet all three of the submarine boys watched their prisoner, cat-like, for any new outbreak.

“Now, roll over on your face, if you want us to believe you’re going to be good,” ordered Jack.

Though he swore, under his breath, Millard obeyed.  Then something flashed in the night—­handcuffs that Jack had brought away from his meeting with Lieutenant Ridder at the hotel.

Click!  The steel band snapped into place around Millard’s right wrist.

“Hold on—­not that!” protested the prisoner, hoarsely.

“Yes; even that!” mocked Eph, picking up a fragment of rock.  “And keep quiet, unless you want me to batter your head in!”

It was this rough, vigorous sea-talk, backed by a belief that young Somers would prove equal to his threat, no doubt, that made Millard allow his left wrist to be brought over to meet the right.

“You’ve got those things on too tight,” complained Millard, sullenly.

“No-o-o, I don’t think so,” retorted Captain Jack, after looking.  “We need ’em as tight as we can have ’em, without causing pain, when we have a fellow like you to deal with.  Now, what was that explosion?”