A quick, short message arrived in telegraphic code: 'Hold out. Am working on lock.'
Harry replied: 'The water is rising. Hurry.'
He did not know who his intended rescuer might be. It seemed improbable that Marquette could have
returned. Possibly Professor Whitburn had discovered the situation.
He waited, and heard slight clicks from the other side of the door. He looked toward Arlette. The girl lay
exhausted, her eyes closed.
Harry tapped: 'Must save girl here with me.'
There was no reply. Then a sudden thought occurred to Harry. He tapped another message:
'Water coming through open sluices. They were opened after door closed. Must be controlled outside of
this room.
The clicking sounds ended abruptly. Harry's last piece of information had evidently given the rescuer an
idea.
'Will seek sluice control,' came the message. 'You can save girl.'
THE final statement dumfounded Harry. How could he save Arlette? They were both prisoners here; if
one could be rescued why not the other? He must discover what was meant. He quickly tapped back a
single word:
'How?'
The response was immediate.
'Through tube.'
The meaning dawned on Harry. This was the room from which Marquette had shot the torpedoes!
Would it be possible to send a human being the same way?
Harry remembered that there was an underground channel that led to the lake. It must be a hundred
yards in length. Such a trip under water would be impossible.
He turned his lamp toward the torpedo tube. He saw one of the torpedoes standing by the wall. Part of it
still extended from the water.
Harry descended the steps, and found that the water nearly reached his armpits. He walked to where the
torpedo stood, and managed to hoist it into the carriage that stood in front of the tube.
He unscrewed the metal end of the torpedo. It was hollow, and contained ample room for a person.
There were no wing attachments to the shell; evidently those were put on when the experiments were
made.
How long could a person live, within that container? Not long, Harry thought. At the same time, one
could not live long in this submerged chamber.
Then he noted a peculiarity in the cap of the experimental torpedo. It had slots, which were backed with
metal strips that could be moved away.
Harry did not know the exact purpose of these; they probably had to do with some invention planned by
Professor Whitburn; but they would solve the problem that was now involved.
Harry seemed to have gained new strength. He lifted Arlette, resting her on his good arm, and carried her
to the torpedo tube. She did not realize what he was about until he had slipped her into the shell. Then
she gazed at him in bewilderment.
'What—what are you doing?' she asked.
Harry smiled reassuringly. He was shoulder-deep in water now. The high-set tube was just barely free of
the rising flood.
'Sending you to safety,' he replied. He lifted the cap of the torpedo. 'Do you see these movable metal
pieces in the cap?'
'Yes,' replied Arlette.
'Wait until the torpedo is floating steadily,' said Harry. 'Then open the one that is above you. It will let in
air.'
'But Harry!' exclaimed Arlette, as she began to understand. 'I can't leave you here -'
Harry had expected to hear her say that. He smiled grimly, as he was about to lower the cap of the
torpedo.
'I'll be along later,' he said.
He closed the cap, and shoved the torpedo into the tube. During the past two days, he had been studying
the projection of torpedoes from submarines, from textbooks which the professor had marked for him.
He recognized the mechanism of this tube.
Harry hung close to the wall and gripped the apparatus. He released the torpedo; it was discharged from
the tube.
Arlette was off on her journey!
HARRY was forced to swim as he made his way back to the steps. By standing on the uppermost place,
he could last a little longer.
He watched the gaining flood, as it seemed to swirl upward. He was in the highest possible position; yet it
was coming almost to his shoulders.
He knew that he must meet death alone; but he was willing. He had saved Arlette.
It was impossible for him to leave by the same route. He could not have entered a torpedo and also have
discharged it. So he must die alone—here beneath the surface of Death Island—unless—unless—
The water was up to his neck. He could see it swirl on the level with his eyes. It still continued to swirl,
but it rose no more.
There was a clicking behind him. Some one was again working at the steel door. Harry tried to tap a
message, but his hands were numb, and his efforts were feeble.
'Hold on -'
The reply was encouraging, yet time seemed endless. Harry knew now that the water was no longer
rising. His rescuer had found the hidden switch that controlled the sluices.
It must have been a long, heart-rending search. Stokes had probably fixed that secret control
somewhere—arranged it so that he could drown any who were trapped within this den of death.
The steel door swung open. A flashlight gleamed into the dark chamber. A black form stooped quickly,
and a powerful hand seized Harry Vincent as he was about to topple into the flood beneath.
WHEN Harry opened his eyes, he found himself lying in the bed of his room on the second floor. Two
persons were beside him. One was Vic Marquette; the other was Arlette DeLand.
'Arlette,' said Harry feebly. 'Tell me -'
'The torpedo floated to the shore,' explained Arlette. 'I managed to open the cap and get out. Then this
man, Mr. -' she looked at Vic Marquette.
'Crawford's my name,' said Marquette calmly. 'Those scoundrels rode me all over the lake, Vincent.
Then they ditched the motor boat at Harvey's Wharf.
'By that time I knew where I was; and I figured they knew that I was with them. I popped out on them,
before they had a chance to plug me under the sacks. They were on the wharf; but they skipped before I
had a chance to shoot at them.'
'Professor Whitburn,' said Harry. 'Is he—all right?'
