Following the excited announcement by Mike that an airship was prowling about over the mountains and Leroy's sudden cry of exultation at the prospect of a struggle for supremacy above the clouds, there was for a moment absolute silence in the hotel room where the boys stood. Finally Pedro entered and closed the door.

Ned walked to a window and looked out. The day was fading, and already the feet of the distant mountains were wrapped in purple twilight. The window faced the north, giving a fair view of the city and the Andes as they strung along in that direction, looking like a chain of bald heads lifting from the obscurity of a fog. The airship was not in sight from where he stood.

Pedro saw what he was looking for and stepped to his side, one hand pointing off to the east.

"Out there!" he said.

"When did you first see it?" asked Leroy, not waiting for Ned to conduct the cross-examination.

The Indian talked with Mike for a moment.

The latter did not seem to understand all that was said to him, but presently he turned to Ned.

"He says he saw it only a minute before he came here," he explained. "He says a lot more that I can't understand. I've been here only a month, and I'm not quick at learning new speech."

"Ask him if he knows whether she landed anywhere near the city," Ned directed.

The Indian did not know. The airship was over the mountains when he first saw it, and that was all he could say about it.

"Do you think we've been followed down here?" asked Jimmie.

"Of course!" Leroy broke in. "What else would an airship be here for just at this time? And if she wasn't sneaking about after us, what would she be hanging up there in the sky for? Why doesn't she come down to town, like we did?"

"It may be that the arrival of this airship just at this time is a coincidence," Ned said, "but it seems to me that there is something significant about it. I have felt all along that we were not yet rid of the rascals who tried to make us trouble at San Francisco."

"Some one must want the cattle concession that Lyman has pretty badly," Leroy ventured. "Well, we'll, have to run away from them, I take it!"

"Then how are we going to find out where this Lyman person is?" demanded Jimmie. "No, Sir!" he went on, rubbing his freckled nose in meditation. "We've just naturally got to bust 'em up!"

The proposition was indeed a serious one. If the airship was really there to take note of the activities of the boys on the Nelson, the situation could hardly be improved by following either line of conduct suggested by the boys.

Nothing could be gained by "running away" from the unwelcome visitor. Nothing was to be gained by following the advice to "bust 'em up." A race would only serve to draw the Nelson away from the point of action, away from the place where Lyman was held in captivity. To "bust 'em up" would be to set all the official rings of Paraguay in operation against the lads, place the Boy Scouts under the ban of the law!

"If we only knew just where to find this Lyman person," Jimmie went on, "we might swoop down an' get him an' give the lobsters a run for their money."

"Perhaps," Ned suggested, "we'd better wait for this new navigator of the air to show us where he is."

"I see him doing it!" cried Leroy.

"You bet he will!" Jimmie cut in. "He'll hang around the point of danger! He'll show us where the man is by standing guard over him! What?"

"That's my idea," Ned replied, "still, he may devote his energies to keeping track of us. One can never tell what an enemy will do."

"Well," Leroy said, "I'm going back to the Nelson. There's a chance of the lobster dropping down and trying to cripple her."

"A very good idea," Ned agreed.

Jimmie and Mike hastened away with Leroy, but Pedro remained at the request of Ned. A plan for meeting the emergency was already forming in the active brain of the Boy Scout, and an important detail depended on information which the Indian might be able to give.

Before opening the question, however, Ned, motioning to the Indian to follow, made his way to the flat roof of the hotel building. There he found several men, smoking, chatting, and watching the airship, now almost directly over the city. In Peru many houses are built with especial reference to providing a lounging place on the roof.

It was growing darker, and the lights of the airship shone brightly against the dimming sky. The aviator was now circling around the city, dropping lower at times, then skimming in spirals to a higher point. While Ned stood watching the machine, realizing that the fellow in charge was no novice in aviation, a gentleman whom he had noticed three times before that day observing him closely advanced and stood by his side. He was a well dressed, clean-shaven man of perhaps thirty, with an intelligent face, a bustling manner, and a suit of clothes which Jimmie would have described as "loud enough to lead a circus parade."

"Evidently an American commercial traveler," Ned thought, as the stranger stood by his side a moment without speaking, his eyes fixed on the airship.

"She goes some, eh?" the stranger observed, presently.

"The aviator seems to know his business," Ned admitted.

"You came in an aeroplane yourself, didn't you?" asked the other.

Ned answered in the affirmative.

"Thought so," the other went on. "Hadn't seen you about the city until this afternoon, and some one said you came in an airship. Where from?"

"New York," Ned replied, half amused at the impertinence of the question.

"Good old town!" the other exclaimed. "Hot old town! I like it. There's something always going on there. I'm from New York myself, but I'm selling goods for a Chicago firm—steam pumps! I've got the best steam pump in seven countries! Came here to sell to a mining company. Nothing doing. What's your name? Mine is Thomas Q. Collins."

"Nestor," Ned replied, shortly.

"And you're out for fun?"

"That's the idea." Ned did not think it necessary to enter into details.

"Hope you get all that's coming to you! Say, will you give me a ride in that machine of yours? I went out to see it today. Looks to me like it could knock the spots off anything of the kind in the world. I don't know anything about airships, but I do know about steam pumps, and also about machinery. I know a good piece of work when I see it. That boat of yours is a peach!"

"It isn't my machine," Ned replied, "but if we remain here over tomorrow I'll see about granting your request."

The two talked for a moment longer, and then Collins left the roof. Later, Ned saw him moving through the street below in the direction of the place where the Nelson had been left. The boy hardly knew what to make of Collins. He might be a steam pump salesman, just as he had described himself, and, again, he might be a spy sent out by Lyman's enemies to discover the plans of the Boy Scouts—even to wreck the Nelson if possible. He decided to, if possible, learn something of the fellow before taking him on board the aeroplane.

After a time the strange airship fluttered away to the north and then Ned and Pedro descended to the former's room. Sitting at the north window, the two could see the lights of the aeroplane dropping downward, and they concluded that the aviator was seeking a resting place for the night.

"He's going to bed in Inca Valley," Pedro said, watching the descending bird. "It is a good place to hide the machine."

The words were spoken in pretty good Spanish, and Ned turned quickly and asked:

"You speak Spanish then?"

The question was asked in Spanish, and the Indian's face brightened.

"Yes," he said, "but I never suspected that you knew the language."

"Only a smattering of it," laughed Ned, "but, still, I think you can understand what I say to you. As I want you to do most of the talking, we may get on very well together."

"What do you want to know?" asked Pedro.

"First, I want you, after we have had our talk, to go out into the city and find out, if you can, all about that aeroplane. I want to know if it has ever been seen here before, if the aviator comes to the city after descending, if he is a stranger here—all about him, in fact."

The Indian bowed.

"Then," Ned went on, "I want you to find out whether the machine is well guarded. I also want to know what kind of a machine it is, and where it came from. If you think it advisable I want you to get into conversation with the aviator and see what kind of a chap he is."

Another bow from the Indian, whose face expressed pleasure at the prospective employment. Ned pondered for a moment, as if not quite certain of his ground, and then asked:

"How, well are you acquainted with the country lying between Lima and Asuncion?"

"Oh," was the astonished reply, "but that is a long, long distance—two, three thousand miles."

"Yes, I know, but have you ever been over the Andes?"

"Oh, yes. I am a guide."

Ned pondered a moment.

"How far east and south?" he asked, then.

"To Lake Titicaca."

"That is on the boundary between Peru and Bolivia?"

"Yes."

"And you know that country—the country around the lake?"

"Very well, indeed."

"It is a long way from Asuncion?"

"It is barely a third of the way. You will see on the map."

"Well," Ned said, after a short silence, "I may as well tell you what I want. I want to be directed to a place in the mountains where I can securely hide our aeroplane. It must be a hiding place absolutely out of sight, especially from the sky. Do you understand?"

The Indian nodded, a knowing smile on his dusky face.

"You mean to hide from the other airship?" he asked.

"Yes."

"There are caverns near Lake Titicaca."

"So I understand. Caverns which defy exploration. But, you see, I must have a hiding place from which the airship can be brought out with speed and returned in the same way."

"To dodge out and in? Yes, I comprehend."

The two dwelt over the maps and plans until; Leroy and Jimmie came romping in to report that all was quiet at the machine, and that Mike was to remain on guard until midnight, when Jimmie was to relieve him. Then Pedro went out in the city to listen to such talk of the strange airship as was floating about the streets. He was back in a couple of hours with the information that the airship had not landed in the city, and that it had never been seen there before.

"It seems to me," Ned said after the Indian ceased speaking, "that now is our time. We ought to be a long way from Lima before dawn."

"The other fellow'll see us!" Leroy objected.

"We'll have to chance that," Ned replied. "We needn't have any lights you know, and the motors make very little noise. Get your traps ready, boys!"

It was arranged that Pedro was to remain, under pay, in Lima, storing up such information as he could secure against the day of the return of the Nelson. Mike was to remain with him, of course, as there would be no room on the Nelson for him. The young man when told of the plans, objected strenuously to being left, but was finally consoled by the promise that the aeroplane would be sent back after him when opportunity offered.

It was after midnight when all the arrangements were made and the boys passed out of their rooms into the hotel lobby. At that hour they thought the driver of the other aeroplane would be likely to be sleeping. At the very door of the hotel they came upon Mr. Thomas Q. Collins! He strolled up as Ned stepped into the doorway and extended his hand. Ned took it, gave it a perfunctory grasp, and attempted to paw on.

"If you don't mind," Collins said, with a persuasive mile, "I'll walk with you if you are going out to your aeroplane. I've been to bed and find that I can't sleep."

"All right," Ned replied, thinking that he would rather have the man with him than on his way to report the departure of the Nelson. "We are just going to look the ship over—perhaps take a little spin. Come along."

"I should like very much to go with you, in case you decide to go sailing tonight," Collins said. "Perhaps you may be able to arrange it?"

"I'm afraid not tonight," Ned replied, wondering just what this new acquaintance was up to. "However," he added, "you may as well come along and look over the ship."

Collins seemed glad of even this slight concession on the part of the boy, and walked along briskly. Presently, however, he began to fall back, talking with Jimmie, who was a few paces behind. Then, before very long, the little fellow missed Collins. He had disappeared in a dark alley. Ned worried over this when informed of the fellow's strange and contradictory conduct. The man might have gone to make report to the other aviator! This was not a pleasant reflection.

Mike was found sitting in front of the Nelson, talking with a native who was trying to learn all about an aeroplane from, a boy who knew nothing about it himself! It took only a short time to make ready for flight, then the Nelson was up and away, making little noise as she cut the air, her great planes flashing in the light of the moon.

"This is pretty poor, I guess!" Leroy exclaimed, glancing over the mighty map of sea and plain and mountain. "How fast do you want to go?"

"At full speed," Ned replied.

"I should say it would be full speed!" Jimmie said, half covering his mouth with his hand, to keep his words from being blown back down his throat. "That is," he added, "if you want to make a sneak!"

Ned turned away to the north and saw the white planes of the strange aeroplane gleaming in the moonlight. She seemed to stand still for an instant, and then sped off to the southeast. Ned sighed with apprehension, but Leroy laughed.

"Come along, you!" he cried, looking back. "If you want a race, come on, and I'll give you the run of your life!"

The white aeroplane flashed by, going farther to the east, and Ned laid a hand on Leroy's arm as he was about to increase speed.

"Don't hurry," he said, almost screaming the words into the boy's ear.

"I don't want him to beat me!" the driver called back.

"Let him go," Ned commanded. "Play about the scenery a little while, and then we'll go back to Lima."

"Let me catch him!" pleaded Leroy. "Just let me chase around him a couple of times. I want to see him make a sneak when he sees the Nelson in action!"

"Can you do it?" asked Ned.

"Sure I can do it. Just give me a chance. There isn't a machine in the world that can win a race against the Nelson!"

"I'm sure of that," Ned answered, "and I hope that fellow over there won't find it out right away. Let him think he can go by us like we were tied to a cloud, if he wants to. There will come a time when his confidence in his machine will cost him his job!"

Leroy saw that Ned was really in earnest in the expressed wish to deceive the aviator of the rival aeroplane, and also saw that there was good reason for doing so, so he shut off the motors and started to volplane downward.

"No," Ned said, "that's not right. Make him think we're trying to catch him. Give him the impression that we want to overhaul him, but haven't the speed."

"The Nelson will blush red with shame to be bested by a water wagon like that!" Leroy grumbled, but he did as requested.

The white aeroplane's driver appeared to take the bait. He loitered, as if waiting for the Nelson to come up, then circled away from her in great wide swaths. Once he swept around the Nelson, and Leroy almost shed tears of chagrin.

"Just see him!" the boy wailed. "He thinks I've got a dirt cart here! He is putting it all over me! I can go two miles to his one, and yet I'm taking all his guff! Let me get at him! I'll run him down!"

In a short time the stranger, apparently satisfied that he could outfly the Nelson, should he desire to do so, moved off to the south and soon disappeared in the distance.

"Now what?" asked Leroy, half angrily.

"He'll watch for us," Ned replied, "but he won't find us chasing him. Go through some of your flip-flaps and then go back toward Lima. I want to say a few words to that Mr. Thomas Q. Collins."

Half mollified at the thought of getting a little speed out of the Nelson, Leroy drove straight for the zenith. Up, up, up he went, onward toward the stars, shining no brighter for his approach, yet luring him on. All the world below was flooded with moonlight and starlight. The mountains were dim in spots, where higher peaks dominated the light, the Pacific shone in the radiance of the night. The blue dome of heaven rounded away like a precious bowl set with diamonds.

The roofs of Lima drew closer together, apparently, and the whole town looked like a little cluttered point of land. And the mountains and the sea stretched away endlessly, and earth took on the look of a great rug woven with invisible stripes. Up, up, up, until the air became thin and the lungs staggered for breath.

Then the motors were shut off and the ocean and the mountain chains seemed to rise up to meet the aeroplane, sailing at the speed of the fastest express. Over the water and down until even Jimmie clutched Ned's arm and gave forth an exclamation of alarm. Then a turn of a lever sent the Nelson skimming over Calleo and back toward Lima. Avoiding the vacant space where the Nelson had rested before, Leroy, under Ned's directions, landed on the dry sand some distance away.

"Of course that other chap will find us when he comes back," Ned said, when the boys stood on solid ground again, "but we'll try to make him think we're hanging around Peru just for the fun of it."

"Perhaps he won't come back," suggested Leroy. "Then I'll lose my chance of showing him what the Nelson can do."

"I have an idea that he'll be back by morning," Ned replied.

In this the boy was right, for the white aeroplane showed in a couple of hours, just about dawn, circled around the city, hovered for a moment over the Nelson, and then went off to the north again.

"It is a certainty that she is here to butt into our game!" Jimmie said, as the white planes disappeared. "She'll start when we start, an' stop when we stop, an' there won't be any getting away from her. How does she get into the air so quick after we cut loose? That's what I'd like to know."

"Some system of signals, undoubtedly," Ned answered. "Now," he continued, "we'll cuddle up in our blankets here and sleep as long as the natives will let us. Who'll keep awake?"

Each one wanted to be the one to stand guard, but the point was decided by the appearance of Mike and Pedro, who had watched the maneuvers of the Nelson, had noted her landing place, and hastened forward. Thus relieved of the care of the machine, the three boys hastened to the hotel and were soon sound asleep.

It was noon when Ned awoke, brought out of a deep slumber by an impatient knocking at his door. He was out of bed in an instant and, clad only in his pajamas, opened the door and looked out. Mr. Thomas Q. Collins stood in the corridor with a look of alarm on his face.

"Thought I'd never get you out," he said, stepping, uninvited, into the room and taking a chair. "Thought that you ought to know what's been going on."

Ned had little confidence in Collins. The fellow's strange conduct of the night before naturally made the boy suspicious. After requesting a ride in the Nelson, or, at least, the company of the Boy Scouts to the place where the machine had been left, he had disappeared without a word of explanation.

It seemed to Ned that he had good grounds for the belief that Collins had spied around until he had learned that the aeroplane was going up, and had then communicated the information to the man on the white machine. At least, the strange aviator had shown in the air directly after the disappearance of Collins.

But it was no part of Ned's purpose to permit Collins to see that he was suspected. It was rather his idea to keep on good terms with the fellow and watch him for any evidences of treachery. He therefore greeted him cordially and asked:

"Something interesting going on in the city? We did not return until nearly dawn, and I've been asleep ever since."

"You haven't heard about the attack on our aeroplane, then?" asked
Collins, looking Ned over keenly.

The boy tried not to exhibit the least emotion or excitement at the disturbing question. Leaning back in the chair he had taken, he asked:

"The curiosity of the people got the better of their courtesy, eh? I have been afraid of that. Well, I hope the Nelson was not seriously injured."

Thomas Q. Collins had the appearance of one who had expected to unwrap a great sensation and had failed. His face was a study.

"Well, no," he replied. "The fact is, when the rush was made the aeroplane shot up into the air."

"Then one of the boys must have been there," Ned said, calmly, although his heart was beating like a drum.

"The little fellow was there, the one you call Jimmie," was the reply.

"And he went into the air alone?"

"No; at the last minute a Peruvian Indian who has been hanging about the machine ever since you came here went with him."

"Then there is no danger," Ned replied, really feeling relieved at the thought that Jimmie was not alone in the aeroplane. "The lad will bring the Nelson back in good time. Anyway, he is entitled to a little excursion, 'all by his lonely,' as he puts it."

"He can operate the machine?"

"Certainly. He can handle the Nelson easily."

Thomas Q. Collins regarded Ned steadily for a moment, his brusque, salesmanship manner all gone, and then asked:

"'Where are you going from here?"

The fellow was showing his hand at last! Or was this just natural curiosity? At that moment Ned was more interested in discovering something about the attack on the Nelson than in fighting off personal and impertinent questions, so he said:

"We haven't made up our minds as to our future course. By the way, what was the cause of the attack on the aeroplane?"

"Oh," replied Collins, frowning slightly, "there were a lot of people gathered about the ropes, and one of your guards was a little coarse in protecting your property, and there was a blow struck, then the mob rushed the roped-in enclosure. I think there was no one seriously injured."

"I wonder if the other aviator is also having trouble with his machine?" asked Ned, anxious to know what Collins would say about the white aeroplane.

"I don't know about that," Collins replied. "In fact, the other fellow went off to the south soon after the departure of the Nelson."

"Chased Jimmie up, eh?"

"Well, anxious for a race, it seemed to me."

"Has the Nelson returned?" asked Ned, then.

Collins shook his head.

"If you'll excuse me, then," Ned said, presently. "I'll dress and take breakfast and go down to see what's doing."

"Your breakfast will be luncheon, I guess," laughed Collins. "I was on my way to the dining room when I thought of you. If you don't mind I'll wait for you in the lobby. These natives are not very good table companions. I'm sick for the sight of my own countrymen, anyway, and I can't tell you how glad I am to see you here."

Collins went out and closed the door and Ned set about his toilet. He did not know what to make of the alleged steam pump salesman. At times he appeared to be perfectly frank and honest, then there would come to his eyes a look of half-concealed cunning and greed which put the boy on his guard.

However, Ned thought, the correct way to fathom the fellow's intentions would be to remain in his company as much as possible. So the boy bathed and dressed and went down to Collins in the lobby with a cheerful face.

During the meal Collins talked incessantly of the country and his prospects in South America. Ned listened, saying little, even in the short spaces of silence. He was waiting for the fellow to strike some chord which tuned with his actions of the night before. At last it came.

"I'm thinking of going over to Asuncion," he said, when the meal was nearly over. "There are mines over that way, and I may stand a chance of selling a pump. Rotten luck in Peru, and I can't afford to spend all this expense money and not sell a thing. I hear that there are a few Americans over in Paraguay," he added, tentatively, smiling over at Ned.

"I know very little about the country," Ned said, coolly, fearful that Collins would drop that line of conversation, "and I never heard that foreigners of any sort were made welcome in Paraguay. I don't think we'll go out of our way any to visit that hot little republic."

Collins looked disappointed. Ned could see that. In a moment he tried again to bring the subject out, but Ned seemed entirely indifferent.

When the two left the hotel and walked in the direction of the sand lot where the Nelson had been left, the boy was fully satisfied that Collins was in league with his enemies. For all he knew, the fellow might be the very man who was trying to get Lyman's concession away from him. This might be the man who was bribing the crooked military chief to make it impossible for the cattle man to carry out his contract.

"What time did the Nelson leave?" Ned asked, as they drew near a little group of natives standing on the sand lot.

"Not far from nine," was the reply.

"I didn't think Jimmie would be out that early," laughed Ned. "He is a little sleepy head, ordinarily."

Pushing their way into the center of the little crowd, Ned and Collins found Leroy and Mike Dougherty engaged in a heated debate with a police officer who was threatening arrest. Ned stepped back so as not to attract the attention of the boys, and kept his eyes fixed on Collins. In a moment he saw that gentleman give an impatient gesture which seemed to urge the officer on.

Ned thought fast for a moment. He was considering whether or not he had been brought there for the purpose of getting into a row in defense of his chums and being arrested with them. He was heartily glad that the Nelson was out of the way, although he would have been better pleased had he been safe aboard of her.

"These Peruvian officers are too fresh!" Collins said, in a moment. "What do you mean by molesting these boys?" he added, in Spanish, turning to the officer.

"They are charged with assault," the latter replied.

"By whom?" asked Ned, also speaking in Spanish.

"They struck half a dozen citizens," was the indefinite reply. "We must take them to jail."

"I'll give you a bump in the eye if you come near me!" Leroy put in, as he searched the sky eagerly for some sign of the Nelson.

"That wouldn't help matters any," Ned said, speaking in English.
"Go along with the officer, and I'll pay your fine."

Collins looked annoyed at this cautious advice. He came nearer to
Ned and whispered:

"The courts are slow and uncertain here. It may be weeks before the boys will be restored to liberty if they are locked up. If we could get them away into the mountains until the Nelson returns that would end the whole affair."

"And so you want to get me mixed up in it, too!" thought Ned, as the officer glared at him. "You want to get me on a charge of resisting arrest! When we get out of here, Mr. Thomas Q. Collins, I'll see that you get what's coming to you!"

If Collins could have known what was passing in Ned's mind, could have understood how suspicious the boy was of him, he would not have urged the lads, in English, to cut and run. By doing so he merely confirmed Ned's unfavorable opinion of him. From that moment Ned knew him for what he was, and resolved to get him out of the way in some manner.

Leroy and Mike paid little attention to what Collins said, as a shake of the head from Ned gave them to understand what was passing in his mind. In a moment Ned stepped to the side of the policeman.

"You are all right, officer," he said. "You are only doing your duty. The boys will go with you, and I'll pay their fines."

But, as Ned discovered, it is easier to get into jail in Peru than it is to get out.