TWO MEN OF THE AIR.

The news that all their trouble had gone for naught, and that Jack had himself placed his rescue beyond their hands, struck the three newcomers to the valley dumb for an instant. But at last Captain Atkinson spoke:

“Of course, you have not forgotten me, Alvarez?”

“That is hardly likely, seÑor capitan,” rejoined Alvarez, a slight smile playing across his swarthy features; “one does not forget such encounters as our last one.”

“So I perceive. But this time you will not escape so easily. You are to consider yourself my prisoner.”

The Mexican shrugged his shoulders.

“I am not in a position to attempt to escape,” he said resignedly.

“How did you come to be in this valley with Jack Merrill?” was the next question.

Alvarez, who doubtless saw that his best course was to tell the truth, launched into a fairly accurate account of the adventures on the raft, and the thrilling descent into the Pool of Death. Ralph Stetson shuddered as he listened. Walt looked almost incredulous. It seemed hard to believe that any human being could have “shot” that awful cataract and lived.

By this time it was dark, and, as it would have been too dangerous to attempt using the improvised rope ladder at night, Captain Atkinson decided to camp where they were. Alvarez was not bound, as his captors deemed it impossible for him to escape. Instead, he sat around the fire with them, and to anyone not knowing the circumstances he appeared more like a friend or a member of the party than an alien prisoner.

But they had not counted on the wily ways of the ex–cattle rustler. Even Captain Atkinson, old plainsman as he was, was completely taken in by the seeming resignation of Alvarez to his fate. For this reason no guard was placed on the man that night. This Captain Atkinson was to regret bitterly some hours later, for, when day dawned, there was no sign of Alvarez.

The Ranger guessed the truth at once. Alvarez had overheard their talk about the rope ladder and the ponies which had been left tethered in the grass at the falls. There was not the slightest doubt that he had made use of the ladder in the night, and helped himself to one of the ponies. If he had not taken all three they would be lucky, thought the captain.

The boys were anxious to set off in pursuit of the escaped prisoner at once, but Captain Atkinson made them prepare and eat a scanty breakfast first.

“Alvarez must be miles away by this time,” he said, “that is, provided he made the climb in safety.”

After breakfast no time was lost in striking out for the falls. The ladder was just as they had left it, except that one of the cross sticks had snapped, showing that someone must have climbed it in the darkness and missed his footing.

“We are at least fortunate that he left the ladder,” said Captain Atkinson. “I had a half–formed fear that he would have destroyed it.”

“Surely he would not have done such a dastardly thing as that!” exclaimed Walt.

“All is fair in love and war, you know,” rejoined the Captain with a smile, “and Alvarez is at war with us.”

“I’m not bothering so much about him,” said Ralph with a sigh, “in fact, I think it was good riddance of bad rubbish to lose him. It’s poor Jack I’m worrying about.”

“Let us hope that he has found his way to a settlement and that by this time he is on his way back to camp,” said Captain Atkinson cheerfully. “Why, it’s even possible that he may get there ahead of us.”

The cheery tones of their leader greatly heartened both the lads and the climb up the ladder was made in good spirits. As soon as they reached the surface they hurried to where the ponies had been tethered. Walt and Jack’s animals were both there, but the captain’s had gone. Pinned to one of the saddles was a hastily scribbled note on a bit of paper seemingly torn from an old account book.

Captain Atkinson unfolded this missive and read it aloud. It was in Spanish, but he translated as he went along.

“Well,” laughed the captain, “that’s a characteristic bit of Mexican writing. A man steals your horse and breaks his parole and then signs himself ‘your devoted servant.’”

“What’s to be done now?” asked Walt.

“We shall have to take turns riding the remaining ponies double. It will make our progress slow, but it is the only thing to be done. Let us lose no more time but saddle up and get started at once.”

This was done; and half an hour later the three travelers had left beyond ear–shot the sound of the falls that thundered unceasingly into the Pool of Death.

********

The boldest of the unclean birds that surrounded Jack’s unconscious form were quite close to him when in the air above, where some others were still wheeling about before descending, there came a sudden disturbance and flapping of wings. High above the highest of the circling buzzards was what at first appeared to be merely a larger bird of prey. But a second glance would have shown that besides size, this new winged creature possessed many other points of difference from the bird creation. Behind it streaked out a long trail of blue smoke, and it could be seen that seated in it, between the wings, were the figures of two men. It was, in fact, an aeroplane of the biplane type, powerfully engined and commissioned by the Mexican government for use as a scout ship to spy out the haunts of the rebels.

Its two occupants were Lieut. JosÉ Sancho and Lieut. Manuel Diaz of the Mexican army. They had been flying since daybreak, scouting the country thoroughly in search of information of the rebels’ whereabouts. The great flock of buzzards had attracted their attention, and Lieut. Sancho, who was at the wheel, while his comrade scanned the country through field glasses, had steered the airship in the direction of the great birds.

“Can you see anything?” he asked Lieut. Diaz as the airship drove in among the birds, scaring them off with hoarse cries.

“Yes. There is something on the ground.”

“It must be some dead animal. No human being could have found his way into this miserable desert.”

Lieut. Sancho was about to put the airship on its course once more when his brother officer gave a startled exclamation.

“By the saints!” he exclaimed, “this is strange.”

“What do you mean?”

“Why, what attracted those buzzards was no dead steer or horse.”

“What then was it?”

“The figure of a boy or a man lying face downward.”

“Is he dead, do you think?”

“It is impossible to tell.”

“Shall we descend and see?”

“We might as well, although, to speak the truth, I can’t conceive that anyone could have wandered into this desert and lived.”

“Nor I. Still it is our duty to find out.”

“Undoubtedly. Let us land on that little hillock yonder and then we can make an examination.”

Down swooped the great airship, landing without a jar on the bare little hill Lieut. Diaz had mentioned.

As soon as the craft touched the ground the two Mexican officers were out of it, and, after attending to the motor, hastened over the sandy soil to Jack’s side.

“Santa Maria! It is but a boy,” exclaimed Lieut. Sancho as he turned the inanimate form over.

“Todos los Santos, so it is. A fine–looking fellow, too. But is there any trace of life in him?”

For answer Lieut. Sancho shook his head mournfully.

“I fear we have come too late,” he said, bending over Jack to try to catch the least flicker of life.