"Forward!" commanded Tom Parry.
The boys clucked to their ponies.
Not an animal moved.
Surprised, the lads brought their spurs against the flanks that they could feel were trembling a little.
A strange, unlooked for thing occurred.
With whinnies of terror the little animals reared and plunged. Before their puzzled riders could control them every pony in the outfit had whirled suddenly and began plunging along on the back trail.
A chorus of "whoa"s" rose from the Pony Rider Boys. Quirt and spur were used freely, and firm hands on the bridle reins quickly checked the sudden rush. By dint of force and persuasion the boys finally succeeded in forcing their mounts back. That is, all had done so save Stacy Brown. His pony was spinning like a top, while Stacy red-faced and perspiring was uttering loud, angry shouts, driving in spur and raining quick, short blows on the animal"s rump.
The burros had moved just far enough away to be out of reach of Stacy"s plunging animal.
At last it threw itself violently to the ground. Stacy, by a remarkably lively jump, cleared his falling mount, but not a second too soon to save himself from being pinned beneath it.
He sat down on the animal"s head, puffing from his exertions. After a minute, during which the other boys laughed so heartily that their own ponies nearly got the better of them again, Stacy rose and began prodding his mount with the end of the quirt, urging it to get up again.
But the pony refused to budge.
"He"s "hog-tied,"" nodded the guide, riding up. "Let him stay there till he gets ready to move. No use trying to hurry the beast. He"s too much scared."
"Scared at what?" questioned Stacy, looking up apprehensively.
"Yes; that"s what I"d like to know?" agreed Ned. "I don"t see anything that looks like a scare."
The guide was looking down at the animal pityingly, Tad thought.
"What are they so frightened at, Mr. Parry?" asked the lad.
"My boy, they are afraid of the desert," replied the guide solemnly.
CHAPTER II
THE FIRST NIGHT IN CAMP
"The desert?" the Pony Riders gasped in chorus.
"Yes. It is not an uncommon thing. They seem to realize instinctively that there is danger off there. Even in animals that never have been near the desert you will find the same inborn dread of the alkali flats. And I don"t know that I blame them any."
"But is my broncho going to lie here all day?" queried Chunky. "If that"s his idea I might as well give him another argument that will make him change his mind."
"Let him alone. He"ll be better off if you do not force him. When he gets up be gentle but firm with him."
"That"s the strangest thing I ever saw," said Tad quietly.
"Most remarkable," agreed the Professor.
The faces of the boys were serious. They too began to perceive the feeling that had stirred the ponies to resist when turned toward the silent plains that lay spread for mile upon mile before them.
After a few minutes Stacy"s pony scrambled to its feet. The lad was in the saddle in a twinkling.
"Now, I guess you"ll go where I want you to. Whoa! Quit that b-b-b-b-bucking."
The animal had gone into a series of jolting bucks, with back arched and head well down. The fat boy held his seat well. His face was red and streaked with perspiration which ran down it in tiny rivulets under the violent exercise to which he had just been subjected.
The boys forgot the serious side of the incident in their enjoyment of their companion"s discomfiture.
Tom Parry gazed upon the scene with more than ordinary curiosity. It was the first opportunity he had had of observing a Pony Rider Boy in action. At that moment Stacy Brown was most distinctly in action.
Most of the time there was a broad patch of daylight under him, and when he hit the saddle it was with a jolt that seemed as if it must jar his head from his body.
"Put some salt on his tail," suggested Ned Rector.
"Y-y-y-you do it," gasped Chunky, which brought a roar of laughter from the whole party.
"Yes, why don"t you?" teased Tad. "It"s the only way you can make good."
"Salting down horse is not my business," laughed Ned.
All at once the pony whirled, heading down the mountain side with a disconcerting rush that nearly brought disaster upon its rider.
With a shout the rest of the boys urged their mounts into a jog-trot and followed on down the trail as fast as they dared, for the descent was steep and dangerous.
"He"ll break his neck!" cried the Professor.
"After that bucking I"m sure Chunky"s neck is too well fastened to come off," laughed Tad.
Stacy was out of sight. They could hear him yelling at his broncho, so they knew he was still in the saddle and right side up. The other ponies, apparently having forgotten their fear, were following the leader willingly now.
All at once they saw lad and mount burst into view on the plain below.
"He"s on the desert!" shouted Tad.
Laughing and shouting words of encouragement to the fat boy, the Pony Riders hastened to the base of the hill. Stacy Brown was still busily engaged trying to subdue his pony, though some of the lads shrewdly suspected that their companion was urging the animal on in order to show off his horsemanship.
In a moment more they, too, were in difficulties. No sooner had their bronchos set foot on the desert than a sudden panic once more possessed them. Professor Zepplin"s pony whirled on its haunches, then began climbing the rocks, with the agility of a squirrel.
The others, however, had troubles of their own, which saved the Professor from being laughed at. The animals seemed determined not to be forced to go on, and it required severe measures to induce them to take up the desert trail. Tom Parry"s mount did not exhibit the same fear as did the others. Still, it gave him more or less trouble, appearing to be excited, in spite of itself, by the actions of its companions.
At last they succeeded in lining the animals up in an orderly formation. Their next move was to get the burros moving along ahead of them. The way being open and level there was no necessity for leading the pack animals now. These could take care of themselves without danger to the outfit.
"And this is the desert!" marveled the Professor.
"It is," smiled the guide.