of the searchlight fell far away on one
of the cavern's rough walls. He could just make out James Quade
standing there, his back towards them.

He was hacking at the wall with a pick. Presently he dropped the tool
and wrenched at the rock with bare hands. A large chunk came loose. He
hugged it to him and turned and strode back towards the two on the
floor, and as he drew near they could plainly see a gleam of triumph
in his eyes.

"You know what this is?" he shouted. Guinness could only faintly hear
him. "Wealth! Millions! Of course we always knew the radium was here,
but this is the proof. And now we've a way of getting it out--thanks
to your borer! All the credit is yours, Professor Guinness! You shall
have the credit, and I'll have the money."

Guinness tugged furiously at his bonds again. "You--you--" he gasped.
"How dare you tie us this way! Release us at once! What do you mean by
it?"

* * * * *

Quade smiled unpleasantly. "You're very stupid, Guinness. Haven't you
guessed by now what I'm going to do?" He paused, as if waiting for an
answer, and the smile on his face gave way to a look of savage menace.
For the first time his bitter feelings came to the surface.

"Have you forgotten how close I came to going to jail over those
charges of yours a year ago?" he said. "Have you forgotten the
disgrace to me that followed?--the stigma that forced me to disappear
for months? You fool, do you think I've forgotten?--or that I'd let
you--"

"Quade," interrupted the older man, "you know very well you were
guilty. I caught you red-handed. You didn't fool anyone--except the
jury that let you go. So save your breath, and, if you've the sense
you were born with, release my daughter and me. Why, you're crazy!" he
cried with mounting anger. "You can't get away with this! I'll have
you in jail within forty-eight hours, once I get back to the surface!"

With an effort Quade controlled his feelings and assumed his oily,
sarcastic manner. "That's just it," he said: "'once you get back!' How
stupid you are! You don't seem to realize that you're not going back
to the surface. You and your daughter."

Sue gasped, and her father's eyes went wide. There was a tense
silence.

"You wouldn't dare!" the inventor cried finally. "You wouldn't dare!"

"It's rather large, this cavern," Quade went on. "You'll have plenty
of room. Perhaps I'll untie you before I go back up, so--"

"You can't get away w