"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 t.i.ticaca."

"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 t.i.ticaca."