But the moment he released that grip there was a change in Diablo, as though he realized that the man had suddenly trusted himself entirely to his mount. Bull felt a sudden wincing of all that great body; the quarters sank and trembled. He thought at first that it was because the horse was failing under the weight of this ponderous burden; but instinct told him a moment later that it was fear, and a mixture of suspicious anger.

Diablo took one of his long, catlike steps, and paused without bringing up his other foot. In vain Bull spoke to him, softly, steadily. Diablo took another step, quickened to a soft trot, and stopped suddenly. That weight on his back failed to leave him. He began to tremble violently. Bull felt the sudden thundering of the great heart beneath the pressure of his knee.

To the stallion, this man had been a friend, a constant companion. The touch of his hand was pleasant. Pleasanter still was the continual deep murmur of the voice, reassuring, telling him of a superior and guardian mind looking out for his interests. Now that hand was stroking his sleek neck and that voice was steadily in his ear. But the position was the most hated one. To be sure, there was no saddle, no cutting, binding cinch, no drag of cruel Spanish curb to control his head, no tearing spurs to threaten him. But his flanks twitched where the spurs had dug in many a time, and he panted, remembering the cinches. Those memories built up a panic. He became unsure. The voice reached him less distinctly. Moreover it was a strange time of the evening. The light of the day was nearly done; the moon was barely up, and all things were ghostly and unreal in that slant light.

Something of all that went through the mind of Diablo was understood by Bull Hunter. It was telegraphed to him by the twitching and vibration of great muscles, by the stiff arching of the neck, and the snorting breathing. But he was beginning to forget fear. The stallion danced lightly forward, and as the wind struck the face of Bull Hunter he suddenly rejoiced. This was what he had dreamed of, to be carried thus lightly, easily. The weight that had crushed other horses was nothing to Diablo. It made him feel buoyant. He became tinglingly alert. On the back of Diablo not a horse of the mountains could overtake him if he fled; and not a man of the mountains could escape him if he pursued on the back of the stallion.

That thought had hardly formed in his excited mind when Diablo sprang, cat-footed, to one side. It made Bull Hunter sway, and he naturally sought to preserve his balance by gripping the powerful barrel of the horse with his knees. But at the first touch of the knee Diablo went suddenly mad. Exactly what he did Bull Hunter never knew. Indeed, it seemed that Diablo left his feet, shot a dizzy height into the air, and at the crest of his rise did three or four things at once. At any rate, as the stallion landed, Bull pitched from the arched back and hurtled forward and to the right side. He landed heavily against the ground, his head striking a small rock; and he lay there a moment, stunned.

Far off he heard Tod shrilling at him, "Bull! Are you hurt?"

He gathered himself together and arose, "I'm all right. Stay where you are!"

"Don't try him again. He'll kill you, Bull!"

"Maybe. But I'm going to try."

Diablo stood on the far side of the corral in the moonlight, a splendid figure with haughty tail and head. Inwardly he was trembling, enraged. He knew what would come. He had thrown men before, and usually he had tried to batter them to pieces after they fell. This man he had no desire to batter. There had been no saddle, no bridle, no spurs, no quirt—nevertheless, he must not be controlled by the hand of any man! But having thrown the fellow, now other men would run on him, swinging the accursed ropes over their heads, shouting, cursing at him in strident voices. Vitally he yearned to break through the bars of the corral and flee, but the bars were there and he must stay in the inclosure with this friendly enemy. It was not the prostrate man he feared so much as vengeance from other men, for that had always been the way.