That mighty wrench of back and shoulder and arm would have broken the jaw of an ordinary horse; it hardly disturbed Diablo. His head was first tucked back until his chin was against his breast, but a moment later he was head down, bucking as never horse bucked before. One second earlier Hal Dunbar had seemed almost as powerful as the animal he rode; now he suddenly became small. For one thing Diablo wasted no time running against the rope. He followed the line of least resistance and bolted around the wide circle with tremendous leaps, gathering impetus as he ran--then stopping in mid-career by the terrific process of hurling himself in the air and coming down on four stiff legs and with his back humped so that the rider sat at the uneasy apex of a pyramid. And this was merely a beginning. That wild category of tricks which Bull had seen partially unraveled the first time he visited the horse was now brought forth again, enlarged, improved upon, made more intricate, intensified. But well and nobly did Hal Dunbar sustain his fame as a peerless rider. He rode straight up, and a cheer came from the spectators when they saw that he was not touching leather in the midst of the fiercest contortions of Diablo. It seemed that the great brute would snap the very saddle off his back, but still the rider sat erect, swaying as though in a storm, but still firmly glued to the saddle. Even the heart of Bull Hunter warmed to the battle. They were a brutally glorious pair as they struggled. The wrenching hand of the rider and the Spanish bit had bloodied the mouth of the stallion, the spurs were clinging horribly at his sides, and he fought back like a mad thing. He flung himself on the ground, Dunbar barely slipped from the saddle in time, and whipped onto his feet again, but as he lurched up, he carried the weight of the rider again, for Dunbar had leaped into his seat, and as Diablo came up on all fours, it could be seen that the big man had secured both stirrups--the difficult thing in that feature of the fight. Dunbar urged the stallion on with a yell; and swinging the quirt over his head, he brought it down with a stinging cut on the silky flanks of the great horse. Bull Hunter crouched as though the lash had cut into his own flesh. He became savage for the moment. He wanted to have his hands on that rider!