Darkness overtook the party as they unpacked beside a pool of water deep under an overhanging shelf of lava.  It had been a hard day.  The horses drank their fill, and then stood patiently with drooping heads.  Hunger and thirst appeased, and a warm fire cheered the weary and foot-sore fugitives.  Yaqui said, “Sleep.”  And so another night passed.

Upon the following morning, ten miles or more up the slow-ascending lava slope, Gale’s attention was called from his somber search for the less rough places in the trail.

“Dick, why does Yaqui look back?” asked Mercedes.

Gale was startled.

“Does he?”

“Every little while,” replied Mercedes.

Gale was in the rear of all the other horses, so as to take, for Mercedes’s sake, the advantage of the broken trail.  Yaqui was leading Diablo, winding around a break.  His head was bent as he stepped slowly and unevenly upon the lava.  Gale turned to look back, the first time in several days.  The mighty hollow of the desert below seemed wide strip of red—­wide strip of green—­wide strip of gray—­streaking to purple peaks.  It was all too vast, too mighty to grasp any little details.  He thought, of course, of Rojas in certain pursuit; but it seemed absurded to look for him.

Yaqui led on, and Gale often glanced up from his task to watch the Indian.  Presently he saw him stop, turn, and look back.  Ladd did likewise, and then Jim and Thorne.  Gale found the desire irresistible.  Thereafter he often rested Blanco Sol, and looked back the while.  He had his field-glass, but did not choose to use it.

“Rojas will follow,” said Mercedes.

Gale regarded her in amaze.  The tone of her voice had been indefinable.  If there were fear then he failed to detect it.  She was gazing back down the colored slope, and something about her, perhaps the steady, falcon gaze of her magnificent eyes, reminded him of Yaqui.

Many times during the ensuing hour the Indian faced about, and always his followers did likewise.  It was high noon, with the sun beating hot and the lava radiating heat, when Yaqui halted for a rest.  The place selected was a ridge of lava, almost a promontory, considering its outlook.  The horses bunched here and drooped their heads.  The rangers were about to slip the packs and remove saddles when Yaqui restrained them.

He fixed a changeless, gleaming gaze on the slow descent; but did not seem to look afar.

Suddenly he uttered his strange cry—­the one Gale considered involuntary, or else significant of some tribal trait or feeling.  It was incomprehensible, but no one could have doubted its potency.  Yaqui pointed down the lava slope, pointed with finger and arm and neck and head—­his whole body was instinct with direction.  His whole being seemed to have been animated and then frozen.  His posture could not have been misunderstood, yet his expression had not altered.  Gale had never seen the Indian’s face change its hard, red-bronze calm.  It was the color and the flintiness and the character of the lava at his feet.