e him?" whispered Hal, quivering.

"No; too dark for that, and, besides, he was too quick. But we must
hustle to alarm someone."

"There's a watchman in the yard," Hal replied. "He ought to be getting
busy."

"I don't hear any hail, or any shot," Jack replied. "Hal, old fellow,
we've got to do something ourselves."

"Well, we can climb the fence as well as that stranger did."

"We'd better. Here, take the flashlight gun. Pass that and the camera
up as soon as I get to the top of the fence. We can't leave our outfit
outside--it's worth too much money."

With that Jack Benson swiftly found a knothole in which he could get
a slight foot-hold. With that start he was quickly up on top of the
ten-foot fence. Bending down he took camera and flashlight "gun."
Hal hurriedly followed. Down in the yard, they started speedily
though softly forward, going by impulse straight toward the submarine's
shed, though keeping in the shadow of other buildings.

Arrived at one corner of the office building, young Benson, who was
in the lead, signaled a stop. Hal halted just behind him.

"It's the submarine, all right, that the fellow's after," whispered
Jack excitedly, as he peeped. "Make him out over there, at the door?
Gracious! He's unlocking and throwing the padlock off. And, blazes!
Can't you make out who it is, Hal?"

"Josh Owen! But he gave up his keys."

"He had at least one duplicate, then," declared Jack, in a tremulous
whisper. "There, he's gone inside. Come on, Hal--soft-foot! We'll
take a near look at what he's doing."

There was some distance to be traveled, and it had to be done with
the utmost stealth. Whatever Josh Owen--if it was truly he--was
doing in the submarine shed, the young shadows did not wish to put
him on his guard until they had caught him red-handed.

"Where's the night watchman while all this is going on?" wondered
Jack as he tip-toed forward. It was afterwards discovered that the
watchman, who sometimes drank liquor, was at this moment sound asleep
in one of the sheds. There was no time to be squandered in looking
for him if Josh Owen was to be followed and foiled.

Creeping to the now open door of the submarine's shed, Jack, who was
in the lead, took a peep inside.

There was a dim light in there, though it came from the further side
of the hull. Benson signaled, and his friend followed him, stealthily,
a step or two at a time, around to the stern of the "Pollard" as she