lon, he turned to the downward sloping trail
and began the descent. He moved slowly and carefully, testing each foot
of the way with a ponderous, insulated boot for the sudden slickness
that would announce the dangerous ice.

Nellon was swept with relief. His blood rushed through his veins in a
sudden fierce singing. Now, now! The broad, metal back of Big Tim's suit
spread before him. Far down below the gleaming ice waited.

Nellon took swift steps forward, his arms coming up. The rushing in his
ears leaped to a high pitch. He sucked in a breath, held it. Then--

Nellon slipped. It must have been a small patch of ice undetected by
Austin. But Nellon slipped, lost balance, crashed into the other.
Together they went whizzing down the trail toward the frozen lake. It
was a long slide, but incredibly swift, and confusion and surprise made
it seem all the shorter. What happened took place too quickly for
thought to follow or prevent.

* * * * *

They caromed onto the ice of the lake. With a gleeful, demoniac howl,
the terrible wind swooped down upon them, swept them with increased
speed toward the edge of the falls. Though still half stunned by the
sudden catastrophe, they reacted with the instinct of long conditioning,
tried frantically to retard their swift flight over the ice. But it was
futile. Their gouging metal fingers could find no purchase in the glassy
smoothness over which they sped. And before friction could slow them
even the merest of trifles, they were swept over the edge of the falls.

They went over, but not down upon the jagged ice teeth bared hungrily
below. Nellon's attempted shove had given them both an added impetus,
and they had shot over the ice at an angle which landed them upon the
snow banked on the farther side of the gorge.

In that far distant day when the heat of Saturn had been great enough to
cloak its satellites in warmth, the gnawing of the falls had worn steep
sides in the gorge. And though the snow upon which the two men had
fallen was thick and soft, it was not enough to hold them, and they went
rolling end over end, in great clouds of powdery white, to stop only
when they had reached the bottom.

[Illustration: Helplessly the two men hurtled down the snowy slope]

For long moments they lay still. A thick pall of settling snow hung on
the frigid air. The wind seized portions of this and sent them whirling
and twisting in fantastic gyrations.

The