Brown men, almost naked and on horseback, darted in and out among the buffaloes, shooting and stabbing. They were muscular men, fierce of countenance, and their long black hair streamed out behind them. Some carried rifles and muskets, and others carried lances and bows and arrows.

"Lipans," said Obed, "one of the fiercest of all the southwestern tribes. They belong mostly across the Rio Grande, but I suppose they've come for the buffalo. Ned, we're not wanted here."

After the single look they were away toward the north, moving at a smooth and easy gallop. They were truly thankful now that the horses they rode were so large and powerful, evidently of American breed. It was not difficult to increase the distance between them and the herd, and they hoped to slip away before they were seen by any of the Lipans. But a sudden shout behind them, a long, piercing whoop showed that they had reckoned wrong.

The two looked back. A group of warriors had gathered in advance of the band, and it was obvious, as they galloped on, that they had seen the two fugitives. Two or three shook their long lances, and pointed them straight at Ned and Obed. Then uttering that long, menacing whoop again, the group, about twenty in number, rode straight for the two, while the rest continued their work with the herd.

"It's a chase," said Obed. "Those fellows want scalps and they don't care whether we're Texans or Mexicans. Besides, they may have better horses than the Mexican ponies. But it's a long chase that has no turning, and if our horses don't stumble we'll beat them. Look out for potholes and such places."

They rode knee to knee, not yet putting the horses to their full speed, but covering the ground, nevertheless, at a great rate. It seemed play for their fine horses, which arched their necks and sped on, not a drop of perspiration yet staining their glossy skins. Ned felt the thrill, as the ground spun back under his horse's feet, and the air rushed past his face. It did not occur to him that the Lipans could overtake them, and their pursuit merely added a fresh spice to a magnificent ride.

He took another look back. The Lipans, although they had lost ground, were still following. They came in a close group, carrying, besides their arms, shields, made of layers of buffalo hide. Several wore magnificent war bonnets. Otherwise all were naked save for the breech-cloth, and their brown bodies were glistening with war paint. Behind them, yet came the black front of the buffalo herd, but it was a full mile away.

Obed looked also, and his heart smote him. Older and more experienced than Ned, he knew that with the fierce Lipans the most powerful of all lures was the lure of scalps. Just as the wolf can trail down the moose at last, they could follow for days on their tough mustangs. But as he shifted his good rifle a bit he felt better. Both he and Ned were splendid marksmen, and if the chase were a success for the Lipans there would also be a bitter fight at the end of it.

Now he and Ned ceased to talk, the sun blazed down on the plain, and on sped the chase, hour after hour.