“It looks pretty hopeless; doesn’t it?” said Mr. Fenwick, as he and Mr. Damon were on their way back to the sleeping shack.

“Yes, it does.  Our signal hasn’t been seen, no ships have passed this way, and our wireless appeal isn’t answered.  It does look hopeless but, do you know, I haven’t given up yet.”

“Why not?”

“Because I have faith in Tom Swift’s luck!” declared the eccentric man.  “If you had been with him as much as I have, up in the air, and under the water, and had seen the tight places he has gotten out of, you’d feel the same, too!”

“Perhaps, but here there doesn’t seem to be anything to do.  It all depends on some one else.”

“That’s all right.  You leave it to Tom.  He’ll get an answer yet, you see if he doesn’t.”

It was an hour past midnight.  Tom tossed uneasily on the hard bed in the wireless shack.  The telephone receiver on his ear hurt him, and he could not sleep.

“I may as well sit up for a while,” he told himself, and he arose.  In the dimness of the shack he could see the outlines of the dynamo and the motor.

“Guess I’ll start her up, and send out some calls,” he murmured.  “I might just happen to catch some ship operator who is up late.  I’ll try it.”

The young inventor started the motor, and soon the dynamo was purring away.  He tested the wireless apparatus.  It shot out great long sparks, which snapped viciously through the air.  Then, in the silence of the night, Tom clicked off his call for help for the castaways of Earthquake Island.

For half an hour he sent it away into space, none of the others in their shacks below him, awakening.  Then Tom, having worked off his restless fit, was about to return to bed.

But what was this?  What was that clicking in the telephone receiver at his ear?  He listened.  It was not a jumble of dots and dashes, conveying through space a message that meant nothing to him.  No!  It was his own call that was answered.  The call of his station—­“E.  I.”—­Earthquake Island!

“Where are you?  What’s wanted?”

That was the message that was clicked to Tom from somewhere in the great void.

“I get your message ‘E.  I.’  What’s wanted?  Do I hear you right?  Repeat.”  Tom heard those questions in the silence of the night.

With trembling fingers Tom pressed his own key.  Out into the darkness went his call for help.

“We are on earthquake island.”  He gave the longitude and latitude.  “Come quickly or we will be engulfed in the sea!  We are castaways from the yacht ‘resolute,’ and the airship ‘whizzer.’  Can you save us?”