e told you. Go ahead and prepare your explosive,
Bruce. I'll do what I can for Uncle while you're working."

Dixon donned his lead-cloth hood and tunic again and set to work. Ten
minutes later he turned to Ruth with a slender foot-long cylinder of
lead in his hand.

"Ruth, will this fit your Uncle's projectile?" he asked.

"Easily," she assured him. "But isn't it frightfully dangerous to
carry in that form?"

"No, it's absolutely safe now, and will be safe until this stud is
turned, releasing the activating gas from one compartment to mingle
with the radium compound in the other section. Then the cylinder will
become a bomb that any sharp jar will detonate."

"All right, let's go then," Ruth answered. "Have you any more of those
lead clothes that I can wear? I could wear the globe head-piece that
Uncle wore, but it would loom up in the dark like a searchlight."

Dixon did not protest Ruth's going with him. There was nothing further
that could be done for Emil Crawford for hours and in the hazardous
sally to Crawford's laboratory he knew that Ruth's cool courage and
quick wits would at least double their chances for success in their
desperate mission. He provided her with a reserve hood and tunic of
lead cloth, then handed her a tiny leaden pellet.

"Keep this for a last resort," he told her. "It's a contact bomb that
becomes ready to throw when this safety catch is snapped over. I wish
we had a dozen of them, but that's the last capsule I had and there's
no time to prepare more."

He fished a rusty old revolver out of a drawer, and placed it in his
pocket. "I'll use this gun for a last resort weapon myself," he said.
"The action only works about half the time, but it's the only firearm
in the place."

* * * * *

The green moon was still high in the sky as Ruth and Dixon emerged
from the tunnel, but it was already beginning to drop gradually down
toward the west. Dixon wheeled his disreputable flivver out of its
nearby shed. With engine silent they started coasting down the rough
winding road into the valley.

For nearly two miles they wound down the long grade. Then, just as
they reached the valley floor they saw, far up among the rocks to the
left of the road, the thing they had been dreading--the bobbing
opalescent globe that marked the presence of one of the Centaurians'
hideous hybrids. The shimmering globe paused for a moment, then came
racing down toward them.

The ne