days." Fuller's tone was
impatient and his words came painfully. "You leave that part of it to
me, Fenton," he gasped. There was a fleck of blood at his lips.

As the scientist stumbled on through the mists, Luke's doubts increased
and he began to lose his respect for the man's intellect and for the
cunning which had enabled him to outwit the neutralizing energies used
by the guards. After all, he was a weak and puny specimen. They all
were, the smart guys who held the people of two worlds in their power by
exercising the knowledge they had learned from books. And this one had
failed even in that; whatever he might have been, he had run afoul of
the law himself and was already a doomed man. Tricks! This trick of
Fuller's had gotten them away, but of what use was it without the brute
force necessary to carry on to a successful end?

The brawn Tom had spoken of so slightingly was what they needed from
this time on, and nothing else would save them. Luke had that brawn;
Fuller did not. The scientist slipped and nearly lost his balance at the
edge of a fissure, but Luke made no move to help him. It was every man
for himself at this stage of the game.

* * * * *

Increasing difficulty came with every step. Now they were sliding and
rolling into a deep crater, now scrambling up its steep sides with hands
torn and bodies bruised by the jagged boulders. A yawning crevasse
opened before them and they were forced to skirt its edge for fully a
half mile in the wrong direction before they found a crossing. And the
cold was unbelievably intense. Numbed and silent, with their eyes half
blinded and lungs seared by the frosty air, they struggled on toward the
three pillars of flame.

And still Tom Fuller carried on, though Luke was now in the lead.

They had covered probably half the distance to the flaming columns when
shouts arose behind them. The guards were on their trail.

"Can't--find us," Fuller panted. "The mists----"

"Hell, the mists are clearing," Luke snarled. "You ain't so damn smart
as you think."

What he said was true. Though there was less light on account of the new
angle with the sun farther below the horizon, the red mist was
definitely lighter in color, noticeably less dense. Visibility was good
to several hundred yards. Luke turned his head, but could see nothing of
their pursuers.

"They can't," Fuller insisted weakly.

Luke, pushed on with renewed vigor, ign