“It’ll be blue all right, sir!  You’ll know it when you come to it by the shadows being blue instead of black.”

And always, the trail had grown rockier, the forests more scattered, the trees scantier and dwarfed, till the way led from clump to clump of scrub pinon amid red buttes and sand hummocks.  And always, the valleys widened and lifted to higher table lands, blasted and shrivelled and tremulous of heat, till the mountains lay on the far sky-line silver strips flecked with purple, like shores to an ocean of pure light.  And always, it was the trail of fleeing horsemen they followed, with one track running aside from the others picking the softest places.

“Only one pack horse and that lame,” Wayland pointed to the foot prints.  “That means they must have provisions cached some where on the way.  If we can tire them out before they can reach their cache, we’ve got ’em.”

Once, where the way led between flanking foot hills, the tracks dipped into a mountain stream and didn’t come up on the other side.  “Hoh!” commented the old man, “that’s easy; you’ll take the right and A’ll take the left; and where the hills lift up ahead, A’m thinking you’ll find the tracks plain.”

All the same, Wayland noticed Matthews frequently moistening his parched lips; and the lakes of light ahead lay a wavering looming veil.  A mile farther on, the ripped punk of a dead pinon betrayed the passing of the fugitives.  When Wayland dismounted to examine the marks, he stepped on a small cactus.  They picked up a trail that led over rocky mesas and dipped suddenly into the deep dug-way of a dry gravel bed.  The sand walls of the dead stream afforded shelter from the sun, and the two riders spurred their bronchos to a canter led by the pack mule.  The sand banks spread, widened, opened; and the mule stopped, both ears pointing forward like a hunting dog.  They rode forward to find themselves looking down on an ocean of light, shimmering orange colored light, with the mountains trembling on the far sky line silver strips necked by purple and opal.  The old frontiersman mowed the sweat from his brows and gazed from under shade of his level hand.

“Sun’s like a shower o’ red hot arrows,” he said.

The sand lay fine as sifted ashes dotted with clumps of bluish-green sage brush and greasewood.  A bleached ox-skull focussed the light with a glaze that stabbed vision.  The ashy earth, the dusty sage brush, the orange sand hills, the silver strip on the far sky line flecked by the purple and opal loomed and wavered and writhed in a white flame.

“Do you see the bluish shade to the shadows?” asked Wayland.

The old man was still shading his eyes from the white heat.  “Do A see mountains, Wayland?”

“Certainly, you do!  Did you think the Desert flat as the sea?”

“That’s just it!  If A see mountains, then A see water too!  It keeps wavering.”

“By which you may know it isn’t water,” warned Wayland.