Both planes were now on fire, and the driver knew of his peril. It seemed to Ned that the fellow's clothes were on fire, too, for he writhed and twisted about as he turned the aeroplane downward.

"He'll get his'n!" Jimmie declared.

The Vixen came down almost like a shot, leaving a trail of flame and smoke behind her. Then the end came.

The charred planes gave way and the frame dropped, carrying the driver with it. They whirled over and over in the air as they came down. The fall must have been fully five hundred feet, and Ned knew that it would be useless for him to seek the man who had worked so much mischief to the Nelson with a view of doing him any service.

Below, the Nelson was sending up sheets of flame. Pedro now ran out of his hiding place and attempted to check the fire, but his efforts availed nothing.

"It is gone, all right!" Jimmie said, with a sigh. "Now, how are we goin' to get out of here? That's what I'd like to know."

"We'll have to get out the same way the others do," Ned replied.

"They have lost their aeroplane too."

"Yes," agreed the little fellow, "but they have a motor car, and we've only our shanks' horses!"

Ned extinguished the burning woodwork on the Nelson and made a hasty estimate of the damage done.

"The motors are not injured," he reported. "If we can get something that will do for planes, we can get her out."

"Then," said Jimmie, "I reckon it's me for the highway! I'll chase that automobile into where it came from. I'll bet I'll find cloth of some kind there."

"It might be better to send Pedro," said Ned.

"All right!" the little fellow agreed. "Then you and I can sleuth about this rotten country in search of gold! They say there's gold in these hills!"

The purr of the motor car's engines now came again, and Pedro hastened up the ledge and followed down into the valley where she lay. In a moment she was out of sight, and the Peruvian was moving toward a rift in the wall of rock to the east.

But Ned, watching from above, saw that there was only one person in the car. Mr. Thomas Q. Collins had been left behind!

"That's strange!" Ned mused. "Why should he remain here? What further mischief has the fellow in mind?"

When Ned returned to the machine he found Jimmie busy polishing the scorched steel work.

"All she needs is new planes!" the lad cried.

"Jimmie," Ned asked, "when you came here yesterday, did the Vixen follow you closely, or did she stand off and on, as seamen say, and take note of your course indifferently? What I want to know is this: Did the driver seem anyway excited when you speeded over this way?

"He followed tight to my heels," replied the little fellow. "Then, when he saw me land, he whirled about and went away."

An idea which seemed almost too good to be true was slowly forming in Ned's brain. Why had the Vixen always followed the Nelson? Why had she spied upon her without in any way interfering?

Again, why had Thomas Q. Collins been left there in the wilderness?

Surely there were no accommodations in sight in those valleys--nothing to subsist on, no shelter from the weather.

He might, it is true, have remained out of a spirit of revenge, hoping to punish Ned for his treatment of him, but this explanation did not appeal to the boy. With the Nelson hopelessly out of repair, he could well afford to leave the lads to their fate, as the chances that they would be able to get out alive--being strangers to that country and, supposedly, to mountain work--were about one to ten.

And so, Ned reasoned, there must be some other incentive for the action taken by Collins. He had a subconscious impression that he knew what that incentive was, but hardly dared to whisper it to himself.

The boy's reverie was interrupted by Jimmie, who had been running back and forth in the valley in quest of wild berries, or something which would serve as food.

"I could eat a whale!" the little fellow shouted.

"Catch a hare and cook him," Ned suggested.

"The hares here are not exactly like our rabbits, but they are good to eat. If you go over into the little jungle below, at the end of this bowl, you might find one."

Ned, still wondering if what he hoped might be true, turned to the cliff which separated the two valleys and began a careful inspection of the rock formation. Away around to the east, under the shelf which ran like a terrace around the elevation, he came upon what he was looking for.

The shelf extended outward from the face of the rock, and under it, setting back into the cliff perhaps a dozen feet, was a cavern which looked out on the valley where the Nelson lay, but from which the machine itself was not in sight.

The floor of the cavern showed traces of human habitation. It had undoubtedly been occupied as a shelter from storms by mountaineers for centuries.

But the evidences of occupation which Ned saw were not those showing distant use. There was a tiny fire burning in a crevice which served as a chimney, carrying the smoke far up into the sky before discharging it.

Scattered about the fire were tin cans, some empty, some containing food of various kinds. Thrown over a heap of broken boxes in a corner was a coat--a tailor-made coat of fine material.

On a little ledge at the rear were a safety razor, a small mirror, and a shaving mug. Ned picked up the coat and thrust a hand into an inside pocket. That, he thought, would be an easy way to ascertain the ident.i.ty of the owner.

In a moment he drew forth a folded paper, covered with figures in pencil. The figures were in columns, as if the maker had been setting down items of expense and adding them up. The total was in the millions. The calculations of a cattleman, covering shipments and receipts!

Ned continued his search of the coat and presently came upon a packet of letters, all enclosed in envelopes and neatly ticketed on the back. They were enclosed in a rubber band, and showed careful handling.

And the envelopes, every one of them, were addressed to Dr. Horace M. Lyman, Asuncion, Paraguay!

CHAPTER X

DINNER IS SERVED

Ned stepped to the mouth of the cavern and looked out. Jimmie was making his way back to the machine, empty handed and evidently dejected. Ned gave a sharp whistle and beckoned to the lad when he looked up.

He did not care to make any unnecessary noise there, for he believed that Collins was not far away.

He was now half convinced that Lyman had been secreted in that vicinity after being abducted from Paraguay; that he had been closely guarded and comfortably provided for, the idea being to keep him out of Paraguay until his concession reverted to the government.

It was his notion, too, that Lyman had inhabited this cavern until the appearance of the Nelson, when he had been removed by his attendants and placed in custody in some other natural hiding place.

Whether he was still in that locality the boy could not say, but of one thing he was certain. That was that Lyman had not been taken away in the motor car.

And so the quest had been shifted! There would now be no need of proceeding to Asuncion. Probably to prevent getting mixed up in the crooked game, the plotters in Paraguay had ordered those interested in the disappearance of Lyman to get him out of the alleged republic.

This would account for his being in the mountains of Peru. It might also account for the presence in Lima of the Vixen and Mr. Thomas Q.

Collins.