d odd pieces of machinery, using a forge, a lathe,
and a small drop hammer for that purpose. They had a gangplank leading
over the waterway to the upper portion of the submarine, and from an
open hatchway of the U-boat ran a number of coils of insulated wire,
evidently carrying power to the electric lights and also to the
machinery.

"They must be getting all their power from the engines of the
submarine," said Jack. "They've certainly got themselves pretty well
fixed down here."

"But how in the world did they manage to find this place?" questioned
Spouter.

"That remains to be found out, Spouter. Probably the German
authorities had some spies around here who found the place for them,
or otherwise they paid some of the natives for the information."

"You know my dad spoke about German U-boat bases along our coast, and
also bases for secret wireless telegraphy plants," put in Fred. "There
is no telling what those rascals are up to."

[Illustration: "A SUBMARINE! WHAT DO YOU KNOW ABOUT THAT?"
_Page 270_]

It was decided that Andy and Randy, accompanied by Spouter, should
make their way back to the opening by which they had gained entrance
to the underground waterway, and then return to Camp Barlight as
quickly as possible and acquaint Captain Dale with what had been
discovered. In the meanwhile, Jack, Fred, and Gif would remain behind
on guard in case the Germans should attempt to make a sudden move.

"We don't know how far along they are with their repairs," declared
the young captain. "It would be just our luck to have them sail away
right under our noses."

"Oh, Jack! couldn't you stop them in some way from doing that?"
questioned Andy quickly.

"I should hope so, Andy. That is, if they really did try to get away.
Of course, they may not be anywhere near ready to leave--although they
have been here for some time according to the noises we have heard.
I'd like to find out something about the other end of the passageway."

"Maybe you can find out by going out with us and around to the other
end of the bay," suggested Spouter.

"I was thinking of that. But for the present I would rather stay right
here and watch these fellows."

It was not long after this when the twins and Spouter departed,
stating that they would report to Captain Dale as speedily as
possible. Then Jack and his cousin and Gif settled down to watch the
Germans.

For Germans they were, beyond a doubt. They were all heavy-set, burly
fel