Grace, never having taken her eyes from the laid-back ears, gave a quick kick with her left foot, catching the pony fairly on the nose. As he hastily withdrew his head, she took advantage of the opportunity to tighten up on the reins, which brought the animal's head well up.

All these preparatory activities were observed with intense interest by cowboys and Overlanders.

"Watch him!" called Hi Lang in an urgent tone.

Grace was watching, her every faculty beat to the task of discovering what the next move of her mount was to be.

The black, as she tightened the rein, reared high in the air until his rider seemed to be standing straight up. One moment she felt that they were both going to fall over backwards, and was about to clear the stirrups to jump. Instead she brought her crop down on the black's head, with a resounding whack.

"Yeow!" howled the cowboys, but Grace did not hear them, for the pony had dropped to all fours, and no sooner had his feet touched the ground than he leaped clear of it, coming down stiff-legged with a jolt that jarred Grace Harlowe throughout her body in spite of her effort to soften the shock by throwing most of her weight on the stirrups.

"He's going to buck," warned the steady voice of Hi Lang.

Grace knew it in advance of the guide's warning, but, though she tugged with all her might, she was not strong enough to get the black bronco's head up so he could not carry out his intention. There followed a series of bucks and squeals, accompanied with flying hoofs, that sent the spectators fleeing for safety.

As for the Overland girl, her head was spinning, her hair was down and her sombrero long since had fallen off and been trampled in the alkali dust by the hoofs of her mount. The jolting she was getting was almost more than she could endure and sharp pains were shooting through her body. This bronco indeed was a master at the art of bucking, but vicious as were his movements the black had not succeeded in ridding himself of his rider.

"Look out!" yelled the guide.