see the craft in that
position. He stepped back a pace, then came gingerly forward.

Evidently the man was astonished to observe the "U-13". He climbed slowly
into the main shrouds. From that position he surveyed the craft more
completely. Again he returned to the deck.

During this examination the lads had remained quietly at their posts, not
caring to make their presence known until they were sure of the identity
of the other. They still remained with their faces at the portholes,
where they observed, so far as possible, every move of the stranger.

Directly they observed the diver pick up the burden he had brought from
the cabin. He hastened to the rail of the wreck. In a moment he had
clambered overboard, letting himself down by means of a line secured to a
belaying pin at the mainmast.

"That's funny!" observed Ned, as the other disappeared from view. "What
do you suppose made him scuttle out of sight so hurriedly?"

"Maybe he, like the warship, saw our name--'U-13'--on the side of the
vessel!" ventured Jimmie. "They all run away from that!"

"It surely doesn't make us many friends!" declared Ned.

"You're right!" answered the other. "It's the original killjoy!"

"Let's dive a little deeper," suggested Jack. "Perhaps we can find out
where this new chap is going with those bundles."

"Perhaps we'll find out how he got here!" added Frank.

"And while you fellows are 'perhapsing'," put in Jimmie, "I'll say that
perhaps we'd better stick out! Perhaps he doesn't want us nosing around
his property, and perhaps he'll touch off a bomb!"

"What's the matter with you lately?" inquired Frank. "You're getting to
be a regular little 'fraid-cat'! You never used to be so timid about
sticking your nose into other people's business!"

"I'm not afraid to go looking into things now, only I've got a hunch that
we'd better not do it, that's all!" answered the lad. "Just because I
happen to want to leave a fellow alone is no sign I'm a 'fraid-cat'. If
you lads want to go anywhere, you tell me the name of the place. I'm game
to stick with you until they turn out the lights!"

"Spoken like a man, Jimmie!" declared Frank. "That sounds like the old
Jimmie we used to know. Now, let's go down a ways."

Harry sprang to the levers. A few shifts of the control brought the
storage batteries to work operating the pumps. With the additional water
admitted by this process, the false "U-13" sank until far below the level
of the rail of