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?"

"Wait a second!" broke in Eph, in a low voice. "Millard had a pal here.
It was the pal I shadowed here. And that pal is running, now, with a
fair-sized bundle that he came here to get."

"He was running when you jumped into this business?" demanded Benson.

"Yes."

"Then the pal is too far away, by this time, for us to catch him by
running after him," decided Skipper Jack. "Now, about that explosion!"

"This wretch had a mine planted up on the hill," explained Hal Hastings.
"I was watching, at the rear, you know, and it happened that I stopped
right close to the hollow where you found me. Then I saw Millard drop
into that hollow, and I took a look-in. I was just in time to see him
bending over to reach for the handle of a magneto battery. Now, I
happened to know that magneto batteries are made for the purpose of
touching off explosives at