"All right, then," exclaimed Billie. "Let's be off. If we use a little strategy, I'm sure we shall succeed."

He turned to mount the horse, which a minute before had been standing a few feet away, but it was gone.

"Where's my horse?" he cried.

The others turned in surprise.

"It certainly was here a minute ago," declared Adrian.

"Then it can't be very far away," insisted Donald.

"It's so far I can't see it," replied Billie.

"There it goes!" shouted Pedro, who had jumped his mount across the track as soon as he heard Billie's cry.

The others looked in the direction indicated, and sure enough, there went the horse about a quarter of a mile away on a dead run and on its back was Billie's late acquaintance, Ab.

"By George," exclaimed Billie angrily as he s.n.a.t.c.hed a rifle from Donald's holster, "I've had enough of that ape. I'll put a stop to his foolishness," and he leveled the rifle.

But ere he could press the trigger, there was a report from another quarter and the horse and its rider hit the dust.

CHAPTER V.

WHEN THE OLD WAS NEW.

A cry of astonishment went up from the quartette and then they stood silent to see what would be the next move.

They did not have long to wait, for presently a tall, gaunt figure strode out of the brambles some yards from the fallen horse and uttered a hoa.r.s.e shout, upon which Ab sprang from the spot where he had fallen and ran toward the newcomer, giving vent to shrill cries as he ran.

"That must be his master," muttered Billie. "I'm glad I didn't shoot the little beggar."

"I'm more interested in the master than in the monkey," said Donald. "He is evidently not a Mexican. Who and what do you suppose he is?"

"An animal trainer from a circus," replied Adrian.

"There are no circuses in this part of the world," commented Billie.

"If he only had a hand organ instead of a gun, I could place him," laughed Donald. "What do you make out of him, Pedro?"

"It's a _saltimbanco_."

"What is that?"

"A man who goes about making people laugh."

"Oh!" from Adrian. "You mean a mountebank?"

"I think so."

"And this chap," ventured Billie, "isn't satisfied with making a monkey of himself, but carries a real one with him."

Pedro laughed. "That seems to be it."

"I'm sorry he killed the horse," said Donald. "We need him."

"Perhaps he didn't," suggested Adrian. "Suppose we ride over and see."

Suiting the action to the word, the boys rode out into the open, much to the newcomer's surprise and consternation.

"Senors," he exclaimed, as he came running toward them, "I am sorry I had to hurt your horse; but I couldn't lose my brother."

"Your what?" asked Billie.

"My brother. My little brother. Could I, Ambrosio?" and he patted the ape on the cheek.

"What do you call him?" asked Donald.

"I call him Ambros...o...b..cause he is so sweet."

"Bah!" exclaimed Billie. "I called him Ab, but he ought to be named Diabolo. But how about the horse?"

"I am afraid I have rendered him quite useless for the present, Senor. I may have broken his leg."

An examination of the fallen animal revealed the fact that while the leg was not splintered, it was so badly injured that the animal was quite useless.

"Have you far to go, Senors?" queried the mountebank.

"Only as far as the Rosario viejo for the present," answered Adrian. "After that----"

"After that," interrupted Billie, "we may not want to go anywhere."

The mountebank looked at Billie questioningly.

"That's what I mean," reiterated Billie. "We are going there to capture a band of cutthroats, but we may have a fight."

The man made a grimace, which was intended for a smile.

"I understand. Can I be of any service?"

Donald eyed him suspiciously.

"What do you think?" he asked.

"You may have noticed how I stopped the runaway," he remarked.