."

The wisdom of this advice was evident when they started out across the
snow-white flat. Every step stirred up clouds of alkali dust that hung
about the fugitives like thick smoke. The impalpable powder penetrated
their clothes, smarted in their eyes, and all but choked them, even
behind the veiling neckerchiefs.

Before they had half crossed the fearful dust flat Carmena was walking
as slowly as the pony. At the far side she sank down beside a
thick-stemmed cactus. Lennon, half delirious from fever, sought to
spring off, with the vague idea of forcing her to ride. He succeeded
only in tumbling upon the sand. The startled pony shied clear. With a
smothered cry, Carmena leaped up to grasp his bridle.

"Close call!" she gasped at Lennon. "If he'd made off--no show for us at
all."

Lennon was too far gone for speech. His canteen was already half empty.
Carmena gave him a sip from her own and dragged him around until his
head lay in the small blot of shade made by a cactus stem. Half an hour
passed before he was able to get back into the saddle. But the rest
appeared to have fully restored the girl's strength. She set off at a
pace that again forced the pony into an occasional jog.

After a time the sheltering ridge ran down into the sandy level of the
desert. Yet Carmena continued to find a route protected by inequalities
of the ground or by growths of cactus and thorn scrub from any eyes that
might be peering across the Basin. As the sun sank nearer to the western
rim of buttes and mesas she kept an ever closer watch to the rear. Her
own and Lennon's canteens were again empty and her seemingly tireless
stride was at last beginning to flag.

By the time the lower edge of the sun touched the rim of the Basin the
fugitives had come opposite a long range of broken hills. Carmena
dragged herself wearily up over an out-thrust spur ridge. Lennon was
swaying in the saddle, and his tongue, like hers, had begun to swell.
But the girl did not offer to open the canteen on the saddlehorn.

At the top of the ridge she hurried the pony down below the skyline and
crept back to peer over a ledge. Far to the rear, across the
shadow-streaked waste, her anxious eyes sighted a group of moving dots.
She ran to seize the pony's bridle and urge him into a jog.

"Must hurry!" she rasped in a thirst-harshened voice. "They're trailing
us--on the lope!"

The alarm shocked Lennon out of his semi-delirium. His relaxing grip on
the rifle