On came the large drove at a trot directly for the river, and a beautiful sight it was as they moved forward in solid mass, with flowing mane and tail and the rising sun glancing upon every variety of color.

The leader was a perfect beauty, black as ink, with glossy hide and long mane and tail—­the equine king of the herd.

With his reins well in hand, his lariat ready, and full of excitement, Billy waited for the horses to reach the stream, which they entered to quench their thirst.

As every head was lowered and the nostrils driven deep into the cool waters, out of the thicket dashed the Boy Horse-Hunter, and the clattering hoofs startled the drove, and in confusion and fright they turned to fly.

Straight as an arrow went the boy toward the black stallion, which attempted to dash by with the mass.

But with an unerring hand the lariat was thrown, the coil settled down over the haughty head, a tremendous jerk followed, and Sable Satan was thrown to the ground.

With an exultant cry Billy sprung from his saddle, and quickly formed a “bow-stall"[1] which, when properly made, is more effective than a severe curb bit—­and placed it upon the animal that was choked beyond the power of resistance.

[Footnote 1:  A “bow-stall” is formed by taking a turn with a rope or lariat between the nostrils and eyes of a horse, and passing one end over the head, back of the ears and tied on the opposite side.  A second noose is then made around the jaws and from this the reins lead back toward the rider, who can then thoroughly manage the animal.—­The author.]

Loosening the lariat around his neck Billy sprung upon the prostrate animal, which, with a wild snort bounded to his feet, and with prodigious leaps started on after the flying herd, his daring young rider firmly seated upon his back.

Finding he could not unseat Billy by bounding, he came to a sudden halt, and then reared wildly; but with catlike tenacity the boy clung to him, and then Sable Satan mad with rage and fright, attempted to tear him from his back with his gleaming teeth.

A severe jerk on the bow-stall however thwarted this, and with a maddened cry the splendid prairie king bounded on once more after the flying herd, a call to Little Grey from Billy causing him to follow at a swift run.

With a speed that was marvelous Sable Satan flew on, directly into the drove, the daring young rider still clinging to him, determined to dare any danger to keep the animal whose capture had baffled the very best horsemen of the plains.

Sweeping through the herd, as though they were stationary, so great was his speed, the black stallion soon left them far behind, and glancing back Billy saw that Little Grey had not cared to venture into the midst of the wild band and was galloping away over the prairies.

Not knowing who might pick him up, and having his rifle, ammunition and provisions strapped to his saddle, he determined to go on after Little Grey, and at once a fierce fight began between the boy and his horse.