When Ruth stumbled to the front of the swaying wagon and seized his shoulder he cast rather an embarrassed glance back at her.

“Stop them!  Stop!” the girl commanded.

“I’d like mighty well to do it, Miss Fielding,” said William, wagging his head, “but these dratted mules have got their heads and—­they—­ain’t—–­no notion o’ stoppin’ this side of the ranch corrals.”

Ruth understood him.  She stared straight ahead with a gaze that became almost stony.  This leading wagon was heading for the break of a ravine into which the trail plunged at a sharp angle.  If the mules were swerved at the curve the heavy wagon would surely overturn.

In twenty seconds the catastrophe would happen!

CHAPTER XV

PURSUING DANGER

When a mule is once going, it is just as stubborn about stopping as it is about being started if it feels balky.  The leading span attached to the covered wagon in which Ruth and her two chums, Helen Cameron and Jennie Stone, rode had now communicated their own fright to the four other animals.  All six were utterly unmanageable.

“Do tell him to stop, Ruth!” shrieked Jennie Stone from the rear of the wagon.

The next moment she shot into the air as the wheels on one side bounced over an outcropping boulder.  She came down clawing at Helen to save herself from flying out of the end of the wagon.

“Oh!  This is too much!” shouted Helen, quite as frightened as her companion.  “I mean to get out!  Don’t a-a-ask me to—­to act in moving pictures again.  I never will!”

“Talk about rough stuff!” groaned Jennie.  “This is the limit.”

Neither of them realized the danger that threatened.  Of the three girls only Ruth knew what was just ahead.  The maddened mules were dragging the emigrant wagon for a pitch into the ravine that boded nothing less than disaster for all.

In the band of Indians riding for the string of covered wagons Wonota had been numbered.  She could ride a barebacked pony as well as any buck in the party.  She had removed her skirt and rode in the guise of a young brave.  The pinto pony she bestrode was speedy, and the Osage maid managed him perfectly.

Long before the train of wagons and the pursuing band of Indians got into the focus of the cameras, Wonota, as well as her companions, saw that the six mules drawing the head wagon were out of control.  The dash of the frightened animals added considerable to the realism of the picture, as they swept past Jim Hooley and his camera men; but the director was quite aware that disaster threatened William’s outfit.

“Crank it up!  Crank it!” he commanded the camera men.  “It looks as if we were going to get something bigger than we expected.”

Mr. Hammond stood behind him.  He saw the three white girls in the rear of the wagon.  It was he who shouted: