ng across the room, he
turned off the electric switch, which threw the wireless room into utter
darkness except for the meagre moonlight filtering through an open
porthole.

Then, just as silently, he re-crossed the room to the door leading to
the battery room; slowly and without a sound he turned the knob and
opened the door to a sufficient width to permit him to peer in. That
room also was in darkness, with only one porthole open.

Cautiously the intruder seemed to be feeling about for something
connected with the batteries.

Listening intently for a moment, to get the exact location of the other
man, Joe flung open the door and made a flying leap in the other's
direction. The man was leaning over, and Joe landed squarely upon his
back.

With a muffled exclamation of surprise the man jerked himself forward
and Joe went hurtling over his head, his arms, however, still clasped
tightly about the other man's neck.

Joe knew in an instant that he was in combat with a man larger and more
powerful than himself, but his own youth and suppleness were in his
favor.

Throwing all his strength into the movement, he twisted about and at the
same time jumped, so that he managed to wrap his legs about the other
man's waist. With another lithe movement he was again upon his back and
reaching for his antagonist's throat, at the same time squeezing with
all the strength of his powerful young limbs upon the other's ribs.

Back and forth across the narrow confines of the little room they
staggered, now one having a temporary advantage, and again the other.
Just as Joe was managing to fasten his fingers in at the throat, and the
other was hammering terrible elbow blows into his stomach, the bigger
man stumbled. As he fell he turned, and his full weight came down upon
the lad, almost crushing him.

Joe was not done for yet, however. With the strength of desperation he
held on to the other fellow's shirt. He felt something hard and metallic
under it, and in a new grasp included that in his fist.

Again the struggle began. Unable to break Joe's grip, the intruder tried
to sink his teeth into the lad's wrist. Failing in this, he gave an
evidence of his strength by rising, dragging Joe upward with him.

There was an instant of terrible whirling about the room, and then the
man landed a smashing blow on Joe's jaw. Still gripping the man's shirt,
and the unknown metallic thing beneath it, the lad reeled. The shirt
ripped, there was