unken submarine.

Now he was completely isolated in the dark, cold tube. The voices
of his companions were not audible. It was a time to test the nerve
of the most callous individual.

Whis-s-s-h! The compressed air came hurtling into the tube with a roar
as of a mighty Niagara. It enveloped him and seemed pressing against
his body like many tons of steel. Instinctively the lad inhaled
deeply and gritted his teeth.

In another moment the bowcap was swung open and then came a rush of air
that shot him forward at a dizzy velocity. As though driven by the
force of a thousand tornadoes the boy felt himself, catapulted out of
the tube and into the cold salt water that closed around him like a
great wall.

His senses reeled and his brain was numbed by the terrible roaring that
pounded in his ears. But he had the will to live and he began his fight.

He brought his legs into play and swam upward furiously. Would he
ever get there? It seemed an eternity as he battled through the mass
of the sea. His arms and legs were getting numb now; his lungs seemed
torn to shreds and his head throbbed with intense pain.

And then, when he was almost lapsing into unconsciousness, his head
shot up out of the waves, and the boy realized that he had reached
the crest of the mountain of water!

For a moment Jack felt paralyzed in every muscle. Then, as he breathed
again the cold pure air of the outside world, his senses came struggling
back through the haze into which he had felt himself drifting and he
was invigorated again. With a great effort the boy turned over on his
back with his face to the sky and floated luxuriously, with arms and
legs limp on the surface of the water.

Resting thus for a time, he turned finally and struck out with a bold
stroke, determined at once to make note of his position. It all came
back to him in a flash---the unknown ship that Sammy Smith had heard
working its way up along the coast.

Was it near? Was it friend or enemy? Would he be seen?

Jack lifted his head and scanned the horizon. It was early morning
and dawn was breaking out of the sky. The first thing that attracted
his attention was a heavy pall of smoke that hung over the water. The
sea was rough.

Carried up on the crest of a wave he beheld the ship that the microphone
had discovered for him in the wireless room. It was now a long way
past the spot where the _Dewey_ lay submerged and had passed northward,
several hundre