The words had hardly escaped his lips when there arose a commotion from the edge of the herd nearest the corrugated land that lay between the herd and the trail back to the Double A.

On a ridge near the cattle a huge, black, grotesque shape was clearly outlined.  It was waving to and fro, as though it were some giant-winged monster of the night trying to rise from the earth.  Sanderson could hear the flapping noise it made; it carried to him with the sharp resonance of a pistol shot.

“Damnation!” he heard himself say.  “Some damned fool is wavin’ a tarp!”

He jerked Streak up shortly, intending to ride for the point where the tarpaulin was being waved before it was too late.  But as he wheeled Streak he realized that the havoc had been wrought, for the cattle nearest him were on their feet, snorting with fright—­a sensation that had been communicated to them by contact with their fellows in the mass.

At the point where the commotion had occurred was confusion.  Sanderson saw steers rising on their hind legs, throwing their forelegs high in the air; they were bellowing their fright and charging against the steers nearest them, frenziedly trying to escape the danger that seemed to menace them.

Sanderson groaned, for the entire herd was on the move!  Near at hand a dozen steers shot out of the press and lumbered past him, paying no attention to his shouts.  He fired his pistol in the face of one, and though the animal tried to turn back, frightened by the flash, the press of numbers behind it, already moving forward, forced it again to wheel and break for freedom.

Sanderson heard the sounds of pistol shots from the direction of the camp fire; he heard other shots from the direction of the back trail; he saw the forms of men on horses darting here and there on the opposite side of the herd from where he rode.

From the left side of the herd came another rider—­Soapy.  He tore ahead of the vanguard of running steers, shooting his pistol in their faces, shouting profanely at them, lashing them with his quirt.

A first batch slipped by him.  He spurred his horse close to Sanderson—­who was trying to head off still others of the herd that were determined to follow the first—­and cursed loudly: 

“Who in hell waved that tarp?”

Sanderson had no time to answer.  A score of steers bolted straight for him, and he groaned again when he saw that the whole herd was rushing forward in a mass.  A common impulse moved them; they were frenzied with fright and terror.

It was not the first stampede that Sanderson had been in, and he knew its dangers.  Yet he grimly fought with the cattle, Streak leaping here and there in answer to the knee-pressure of his master, horse and rider looking like knight and steed of some fabled romance, embattled with a huge monster with thousands of legs.

Sanderson caught a glimpse of several riders tearing toward him from the direction of the camp, and he knew that Carter and the others were trying to reach him in the hope of being able to stem the torrent of rushing cattle.