ack into
the draw, mounted his pony and lashed it into a heavy, sure-footed
gallop.

CHAPTER XIII. SET AFOOT

The tracks of the six horses led down into a rock-bottomed arroyo so
deep in most places that all view of the surrounding mesa was shut off
completely, save where the ragged tops of a distant line of hills pushed
up into the dazzling blue of the sky. The heat, down here among the
rocks, was all but unbearable; and when they discovered that no tracks
led out of the arroyo on the farther side, the Happy Family dismounted
and walked to save their horses while they divided into two parties and
hunted up and down the arroyo for the best trail.

It was just such vexatious delays as this which had kept them always a
day's ride or more behind their quarry, and Luck's hand trembled with
nervous irritability when he turned back and banded Applehead one of
those small, shrill police whistles whose sound carries so far, and
which are much used by motion-picture producers for the long-distance
direction of scenes.

"I happened to have a couple in my pocket," he explained hurriedly. "You
know the signals, don't you? One long, two short will mean you've picked
up the trail. Three or more short, quick ones is an emergency call, for
all hands to come running."

"Well, they's one thing you want to keep in mind, Luck," Applehead urged
from his superior trail craft. "They might be sharp enough to ride in
here a ways and come out the same side they rode in at. Yuh want to hunt
both sides as yuh go up."

"Sure," said Luck, and hurried away up the arroyo with Pink, Big
Medicine, Andy and the Native Son at his heels, leading the two
pack-horses that belonged to their party. In the opposite direction went
Applehead and the others, their eyes upon the ground watching for the
faintest sign of hoofprints.

That blazing ball of torment, the sun, slid farther and farther down to
the skyline, tempering its heat with the cool promise of dusk. Away up
the arroyo, Luck stopped for breath after a sharp climb up through a
narrow gash in the sheer wall of what was now a small canon, and saw
that to search any farther in that direction would be useless. Across
the arroyo--that had narrowed and deepened until it was a canon--Andy
Green was mopping his face with his handkerchief and studying a bold
hump of jumbled bowlders and ledges, evidently considering whether it
was worth while toiling up to the top. A little below him, the Native
S