edes must ride； but the others must walk。
The Indian led off into one of the gray notches between the tumbled streams of lava。 These streams were about thirty feet high； a rotting mass of splintered lava； rougher than any other kind of roughness in the world。 At the apex of the notch； where two streams met； a narrow gully wound and ascended。 Gale caught sight of the dim； pale shadow of a one…time trail。 Near at hand it was invisible； he had to look far ahead to catch the faint tracery。 Yaqui led Diablo into it； and then began the most laborious and vexatious and painful of all slow travel。
Once up on top of that lava bed； Gale saw stretching away； breaking into millions of crests and ruts； a vast； red…black field sweeping onward and upward； with ragged； low ridges and mounds and spurs leading higher and higher to a great； split escarpment wall； above which dim peaks shone hazily blue in the distance。
He looked no more in that direction。 To keep his foothold； to save his horse； cost him all energy and attention。 The course was marked out for him in the tracks of the other horses。 He had only to follow。 But nothing could have been more difficult。 The disintegrating surface of a lava bed was at once the roughest； the hardest； the meanest； the cruelest； the most deceitful kind of ground to travel。
It was rotten； yet it had corners as hard and sharp as pikes。 It was rough； yet as slippery as ice。 If there was a foot of level surface； that space would be one to break through under a horse's hoofs。 It was seamed； lined； cracked； ridged； knotted iron。 This lava bed resembled a tremendously magnified clinker。 It had been a running sea of molten flint； boiling； bubbling； spouting； and it had burst its surface into a million sharp facets as it hardened。 The color was dull； dark； angry red； like no other red； inflaming to the eye。 The millions of minute crevices were dominated by deep fissures and holes； ragged and rough beyond all comparison。
The fugitives made slow progress。 They picked a cautious； winding way to and fro in little steps here and there along the many twists of the trail； up and down the unavoidable depressions； round and round the holes。 At noon； so winding back upon itself had been their course； they appeared to have come only a short distance up the lava slope。
It was rough work for them； it was terrible work for the horses。 Blanco Diablo refused to answer to the power of the Yaqui。 He balked； he plunged； he bit and kicked。 He had to be pulled and beaten over many places。 Mercedes's horse almost threw her； and she was put upon Blanco Sol。 The white charger snorted a protest； then； obedient to Gale's stern call； patiently lowered his noble head and pawed the lava for a footing that would hold。
The lava caused Gale toil and worry and pain； but he hated the choyas。 As the travel progressed this species of cactus increased in number of plants and in size。 Everywhere the red lava was spotted with little round patches of glistening frosty white。 And under every bunch of choya； along and in the trail； were the discarded joints； like little frosty pine cones covered with spines。 It was utterly impossible always to be on the lookout for these； and when Gale stepped on one； often as not the steel…like thorns pierced leather and flesh。 Gale came almost to believe what he had heard claimed by desert travelersthat the choya was alive and leaped at man or beast。 Certain it was when Gale passed one； if he did not put all attention to avoiding it； he was hooked through his chaps and held by barbed thorns。 The pain was almost unendurable。 It was like no other。 It burned； stung； beatalmost seemed to freeze。 It made useless arm or leg。 It made him bite his tongue to keep from crying out。 It made the sweat roll off him。 It made him sick。
Moreover； bad as the choya was for man； it was infinitely worse for beast。 A jagged stab from this poisoned cactus was the only thing Blanco Sol could not stand。 Many times that day； before he carried Mercedes； he had wildly snorted； and then stood trembling while Gale picked broken thorns from the muscular legs。 But after Mercedes had been put upon Sol Gale made sure no choya touched him。
The afternoon passed like the morning； in ceaseless winding and twisting and climbing along this abandoned trail。 Gale saw many waterholes； mostly dry； some containing water； all of them catch…basins； full only after rainy season。 Little ugly bunched bushes； that Gale scarcely recognized as mesquites； grew near these holes； also stunted greasewood and prickly pear。 There was no grass； and the choya alone flourished in that hard soil。
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 redwide strip of greenwide strip of graystreaking 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 crythe 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 headhis 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。
〃Shore he sees somethin'；〃 said Ladd。 〃But my eyes are not good。〃
〃I reckon I ain't sure of mine；〃 replied Jim。 〃I'm bothered by a dim movin' streak down there。〃
Thorne gazed eagerly down as he stood beside Mercedes； who sat motionless facing the slope。 Gale looked and looked till he hurt his eyes。 Then he took his glass out of its case on Sol's saddle。
There appeared to be nothing upon the lava but the innumerable dots of choya shining in the sun。 Gale swept his glass slowly forward and back。 Then into a nearer field of vision crept a long white…and…black line of horses and men。 Without a word he handed the glass to Ladd。 The ranger used it； muttering to himself。
〃They're on the lava fifteen miles down in an air line；〃 he said； presently。 〃Jim； shore they're twice that an' more accordin' to the trail。〃
Jim had his look and replied： 〃I reckon we're a day an' a night in the lead。〃
〃Is it Rojas？〃 burst out Thorne； with set jaw。
〃Yes； Thorne。 It's Rojas and a dozen men or more；〃 replied Gale； and he looked up at Mercedes。
She was transformed。 She might have been a medieval princess embodying all the Spanish power and passion of that time； breathing revenge； hate； unquenchable spirit of fire。 If her beauty had been wonderful in her helpless and appealing moments； now； when she looked back white…faced and flame…eyed； it was transcendant。
Gale drew a long； deep breath。 The mood which had presaged pursuit； strife； blood on this somber desert； returned to him tenfold。 He saw Thorne's face corded by black veins； and his teeth exposed like those of a snarling wolf。 These rangers； who had coolly risked death many times； and had dealt it often； were white as no fear or pain could have made them。 Then； on the moment； Yaqui raised his hand； not clenched or doubled tight； but curled rigid like an eagle's claw； and he shook it in a strange； slow gesture which was menacing and terrible。
It was the woman that called to the depths of these men。 And their passion to kill and to save was surpassed only by the wild hate which was yet love； the unfathomable emotion of a peon slave。 Gale marveled at it； while he felt his whole being cold and tense； as he turned once more to follow in the tracks of his leaders。 The fight predicted by Belding was at hand。 What a fight that must be！ Rojas was traveling light and fast。 He was gaining。 He had bought his men with gold； with extravagant promises； perhaps with offers of the body and blood of an aristocrat hateful to their kind。 Lastly； there was the wild； desolate environment； a tortured wilderness