That night, as may be imagined, the adventurers spent in hearty sleep. Although they had no means of knowing how far behind they were in the race, at the same time they were too exhausted by the exciting events through which they had passed to consider anything except refreshing their wornout frames. But boy nature is a wonderful thing, and both Mr. Joyce and Bart Witherbee were hard as nails, so when the entire party awoke the next day—well over the border line into Arizona—they were as refreshed as if they had rested a week.

Breakfast was over, the auto packed and everything ready for a start when suddenly in the distance a low growling was heard, something like the voice of an approaching thunderstorm.

“Thunder!” exclaimed Billy; “if that isn’t tough luck.”

“Thunder!” echoed Bart incredulously; “not much. Why, the sky’s as clear as a mirror.”

“Well, it’s queer, certainly,” agreed the others, looking about, but as they saw no cause for the queer noise the auto party got aboard and Frank and Harry mounted in the aeroplane.

The desert in this part of Arizona is full of little dips and rises, and from the dip on a river bank where grew a sparse collection of trees, by which the boys had camped, they had not been able to see far across the plain. As soon as Frank and Harry rose in the air, however, they perceived at once what had been the cause of the rumbling sound they had heard.

Not more than a mile away, and coming toward them like the wind, was one of the deadliest perils of the plains.

They shouted warnings to the boys in the auto below.

“What’s the matter?” yelled back Lathrop, who was at the wheel.

“Matter?” shouted back Frank. “There’s a herd of stampeded cattle coming straight for you.”

The effect of these words on Bart Witherbee was electrical.

“Great guns, boys!” he exclaimed; “that’s the worst news we could have. If we can’t escape them we are as good as dead. Put on all the speed you can.”

Only half realizing the terrible nature of the peril so rapidly approaching, Lathrop put on all the speed the auto possessed, and the machine seemed to fairly leap forward. Bart Witherbee stood up in the tonneau the better to see what was approaching behind them. Even he blanched under his tanned, weather-beaten skin as he saw that the cattle, an immense herd, were advancing in a crescent-shaped formation that seemed to make escape impossible.

Billy Barnes, who stood at his elbow, also sighted the maddened steers at the same moment as they rushed over a rise not more than half a mile away now.

“Whatever started them?” he gasped.

“Who can tell, lad, a coyote jumping up suddenly, the hoot of a ground owl, anything will start cattle stampeding when they are in the mood for it.”

The herd came swooping on, but so far the auto, which seemed to be fairly flying over the ground, maintained its lead. The steers were bellowing and throwing their heads high in the air as they advanced, and the noise of their hoofs seemed a perfect Niagara of sound.

“Get your gun out and load. We may have to use ’em before long,” exclaimed Bart Witherbee. “Sometimes the noise of shooting will turn a lot of stampeders.”

“Do you think it will stop them?” asked Billy.

“I dunno,” was the grim reply. “Maybe yes, maybe no. We’ve got to try to save our lives as best we can.”

On and on went the chase, the auto fleeing like a scared live thing before the pursuing peril. Bart Witherbee’s face grew grim.

“Won’t they get tired soon?” asked Billy, who couldn’t see how the steers could keep up the terrible pace much longer.

“Tired,” echoed the plainsman, “not much, lad. It’ll take a whole lot to tire them. Why, I’ve seen ’em go clear over a cliff. They’re like mad things when once they’re stampeded.”

Suddenly the auto came to a stop.

“What’s the matter?” shouted Witherbee, in a sharp tone that showed his anxiety.

For reply Lathrop pointed ahead.

Right in front of them was a deep arroyo or water course with steep banks fully thirty feet in height, effectually blocking progress. The boys were trapped.

“What shall we do?” cried Lathrop with a white face.

“Not much of anything as I can see,” replied Bart with a shrug. “Looks like this is our finish.”

On swept the steers. The boys could now see the angry little red eyes of the leaders gleaming savagely. Their horns were as long and sharp pointed as spears.

“Everybody get out your guns and fire, it may scare ’em,” commanded Witherbee.

Quickly the four revolvers of the party were emptied in the face of the advancing onrush, but not a steer wavered.

“It’s all over,” groaned Witherbee.

But suddenly a dark shadow swept down from the skies so close to the boys in the auto that they could almost feel the rush of wind as the great body swept by.

It was the Golden Eagle.

Frank, who, with Harry, had watched in terrible apprehension the advance of the steers, had suddenly recollected what the cowboys had said about aeroplanes scaring them. Instantly he had set his descending levers and swept in a long, low circle full in the faces of the amazed bovines.

With bellows of terror they turned, wavered and a minute later were in full retreat. They thundered past the auto in a long line, their warm breath almost fanning the occupants’ faces, but none of them came any closer. Wild terror of the mysterious thing of the sky had seized them, and they were off in the opposite direction as swiftly as they had thundered in pursuit of the auto.

“Phew! that was as narrow an escape as ever I want to have,” exclaimed Billy, his face still white as the last of the herd scampered by.

“Same here,” echoed Lathrop.

As for Mr. Joyce and Bart Witherbee they did not say much, perhaps because they realized even more than the boys the terrible death from which Frank’s bold swoop had saved them.

Looking up to where the Golden Eagle was soaring far above them the party in the auto set up a cheer to which Frank answered with a wave of the hand. The next instant he pointed to the westward, and—skirting the banks of the steep arroyo till they found a place where a ford had been made—the boys in the auto followed them.

Late that afternoon the character of the country over which they had been traveling began to change. The road grew rugged and in places great trees grew right up to the edge of the track and overshadowed it. The aeroplane soared far above the treetops, however, and the boys had no difficulty in keeping track of it. Suddenly, however, as they drove along the rough track, Billy, who was driving, stopped the car with a jerk.

“We can’t get any further,” he remarked.

“Why not?” demanded Bart Witherbee.

“Look there.”

The boy pointed ahead a few feet up the road.

A huge tree lay across it, effectually blocking all progress.