He swung wide of even the small sand dunes as he passed them, and he kept a vigilant eye upon the dead rocks that dotted the level at infrequent intervals. Even the cactus clumps received flattering attention; and the little stretches of greasewood that came within range of his vision were examined closely.
At the end of half an hour he had seen nothing unusual. Here and there he had noticed a rattler lurking in the shade of a rock or partly concealed under the thorny blade of a sprawling cactus; and he had seen a sage hen nestling in the hot sand. But these were fixtures—as was also the Mexican eagle that winged its slow way in mile-wide circles in the glaring, heat-pulsing sky.
The rider again halted the black horse. The presentiment of evil had grown upon him, and he twisted around in the saddle, sweeping the desolate vast level with cold, alert, puzzled eyes.
There was no object near him behind which an enemy might lie concealed; the gray floor of the desert within many hundred miles of him was smooth and flat and obstructionless. Far away, half a mile, perhaps, he saw a thrusting knob of rock, with some cactus fringing it. From where he sat in the saddle it seemed that the rock might be the peak of a mountain reaching upward out of the sea of sand and desert waste—but it was barren on sides and top, and would afford no concealment for an enemy, except at its base. And even the base was not large enough to conceal more than a few men.
The rider gazed long at the rock, but could detect no sign of movement near it. He had turned from it, to look again into the western distance, when Purgatory whinnied lowly.
Flashing around in the saddle, the rider again faced the rock. And he saw movement there now. The distance was great, but the clarity of the atmosphere brought a moving object distinctly into his vision. The object was a man, and, like a huge fly, he was crawling rapidly up the sloping side of the rock, toward its peak, which flattened abruptly at the summit.
The man bore a rifle. The rider could see it dragging from the man’s hand; and in a flash the rider was out of the saddle, throwing himself flat behind a low ridge of sand, his own rifle coming to a rest on a small boulder as he trained its muzzle upon the man, who by this time had reached the summit of the rocks in the distance. The rider waited, nursing the stock of the rifle, his eyes blazing, while Purgatory, seemingly aware of an impending tragedy, moved slowly away as though understanding that he must not expose himself.
The rider waited, anticipating the bullet that would presently whine toward him. And then he heard the report of the man’s rifle, saw that the smoke streak had been directed downward, as though the man on the summit of the rock were shooting at something below him.
The rider had been pressing the trigger of his own weapon when he saw the smoke streak. He withheld his fire when he divined that the man was not shooting at him; and when he saw the man on the rock shoot again—downward once more—the rider frowned with embarrassment.
“Don’t even know I’m here!” he mused. “An’ me gettin’ ready to salivate him!”
He got to his knees and watched, curiosity gleaming in his eyes. He saw the man on the rock fire again—downward—and he noted a smoke spurt answer the shot, coming upward from the base of the rock. The rider got to his feet and peered intently at the rock. And now he saw another man crouching near its base. This man, however, was not the one the man on the summit of the rock was shooting at, for smoke streaks were issuing from a weapon in that man’s hand also, but they were horizontal streaks.
Therefore the rider divined that the two men must be shooting at another who was on the far side of the rock; and he ran to Purgatory, speaking no word until he had vaulted into the saddle. Then he spoke shortly.
“They’re white men, Purgatory, an’ they’re havin’ a private rukus, looks like. But we’re doin’ some investigatin’ just to see if the game’s on the level.”
CHAPTER II
A MAN’S REPUTATION
Purgatory moved fast, but warily. The black horse seemed to have caught something of his rider’s caution. For part of the distance toward the rock the animal traveled straight, loping rapidly, but as he neared the little stretch of broken country that surrounded the rock he began to sheer off, advancing with mincing steps, his ears erect, his eyes wide and alert, snorting suspiciously.
Knowing his horse, the rider made no attempt to guide him; he knew Purgatory was alert to any hostile movement on the part of the men who were shooting, and that at the first sign of danger to himself or to his rider he would do what was required of him.
The man on the summit of the rock was still shooting, though intermittently. It seemed to the rider that the man’s target must be elusive or concealed, for the shooter’s actions showed that he was irritated. The other man, too, was still shooting. The rider noted that he, too, seemed to be meeting with failure, for as the rider drew nearer he heard the man curse.
Neither of the two men who were visible to the rider had seen him—neither of them had heard the big black horse gliding over the deep sand of the desert. The rider grinned with grim mirthlessness, edging Purgatory around so that the two men, their backs toward him, were not more than twenty or thirty feet away and entirely exposed to his view.
So intent were they upon their work that they did not even hear the rider’s low laugh as he brought the big black horse to a halt and sat quietly in the saddle, a heavy pistol in each hand, watching them.
The rock, the rider noted, was a huge granite block, rotted from long exposure to the elements, seamed and scarred and cracked. The action of the eternally moving sand had worn an irregular-shaped concave into its southern wall, so that the summit overhung the side. The man on the summit was lying flat on his stomach, leaning far over, still shooting downward. The other man, who was standing at the base, was flattened against it, facing the concave side, shooting occasionally, and cursing volubly.
The rider was curious. Glancing sidelong, southward, he saw two horses not more than a hundred yards away. They were in a depression, behind a sand ridge, which accounted for the fact that the rider had not seen them before.
Sight of the horses brought a widening grin to the rider’s face. He had thought, at first, that the two men were shooting at another man, concealed behind the rock; but the fact that there were only two horses indicated that he had been in error. No man would be foolhardy enough to attempt to cross the desert on foot, and unless a man were a friend he would not be carried upon another man’s horse. Therefore, it seemed to be evident that the target at which the men were shooting was not another man.
And now, convinced that the men had cornered an animal of some kind, and that they feared it too greatly to face it openly, the rider laughed loudly and called to the men, his voice freighted with sarcasm.
“Scared?” he said. “Oh, don’t be. If you’ll back off a little an’ give him room, he’ll just naturally slope, an’ give you a chance to get to your cayuses.”
Both men wheeled almost at the same instant. The man at the base of the rock snarled—after the first gasp of astonishment, baring his teeth in hideous mirth and embarrassment; the other man, startled and caught off balance at the sound of the rider’s voice, slipped, tried to catch himself, failed, and tumbled awkwardly down, scrambling and cursing, to the sand within a few feet of the rider.
Sitting in the sand at the base of the rock, the man who had