The ancient desert instinct of the wild ass, brought down through thwarted generations, never had been lost to them.  They had foreknowledge of danger long before horses or human beings could suspect it.

Danger?  What was it?  Something, surely.  Molly sprang to her feet.  A band of antelope, running, had paused a hundred yards away, gazing back.  Danger—­yes; but what?

The girl ran to the crest of the nearest hillock and looked back.  Even as she did so, it seemed that she caught touch of the great wave of apprehension spreading swiftly over the land.

Far off, low lying like a pale blue cloud, was a faint line of something that seemed to alter in look, to move, to rise and fall, to advance—­down the wind.  She never had seen it, but knew what it must be—­the prairie fire!  The lack of fall burning had left it fuel even now.

Vast numbers of prairie grouse came by, hurtling through the silence, alighting, strutting with high heads, fearlessly close.  Gray creatures came hopping, halting or running fully extended—­the prairie hares, fleeing far ahead.  Band after band of antelope came on, running easily, but looking back.  A heavy line of large birds, black to the eye, beat on laboriously, alighted, and ran onward with incredible speed—­the wild turkeys, fleeing the terror.  Came also broken bands of white-tailed deer, easy, elastic, bounding irregularly, looking back at the miles-wide cloud, which now and then spun up, black as ink toward the sky, but always flattened and came onward with the wind.

Danger?  Yes!  Worse than Indians, for yonder were the cattle; there lay the parked train, two hundred wagons, with the household goods that meant their life savings and their future hope in far-off Oregon.  Women were there, and children—­women with babes that could not walk.  True, the water lay close, but it was narrow and deep and offered no salvation against the terror now coming on the wings of the wind.

That the prairie fire would find in this strip fuel to carry it even at this green season of the grass the wily Pawnees had known.  This was cheaper than assault by arms.  They would wither and scatter the white nation here!  Worse than plumed warriors was yonder broken undulating line of the prairie fire.

Instinct told the white girl, gave her the same terror as that which inspired all these fleeing creatures.  But what could she do?  This was an elemental, gigantic wrath, and she but a frightened girl.  She guessed rather than reasoned what it would mean when yonder line came closer, when it would sweep down, roaring, over the wagon train.

The mules began to bray, to plunge, too wise to undertake flight.  She would at least save them.  She would mount one and ride with the alarm for the camp.

The wise animals let her come close, did not plunge, knew that she meant help, allowed her trembling hands to loose one end of the hobble straps, but no more.  As soon as each mule got its feet it whirled and was away.  No chance to hold one of them now, and if she had mounted a hobbled animal it had meant nothing.  But she saw them go toward the stream, toward the camp.  She must run that way herself.