running out at volcanoes?”

The boys were, perhaps, twenty miles north of Quito, almost exactly under the equator. From the plateau on which they were encamped several ancient volcanoes were in plain view.

“Huh! I guess the volcanoes we see are about burned out!” Carl declared. “At any rate, I don’t hear of their filling in any valleys with lava.”

“I guess about all they do now is to smoke,” Ben suggested.

“And that’s a bad habit, too!” Glenn Richards grinned.

“Now, I’ll tell you what we’d better do, boys,” Glenn said, after glancing disapprovingly at the small fire. “We’d better hop on the machines and drop down about ten thousand feet. I’ve got enough of this high mountain business.”

“All right!” Jimmie returned. “You know what you said about wanting experiences which were out of the way. If you think you’ve got one here, we’ll slide down to the green grass.”

It was late in November and the hot, dry season of the South American continent was on. Far below the boys could see the dark green of luxuriant vegetation, while all around them lay the bare brown peaks of lofty plateaus and lifting mountain cones.

As it was somewhere near the middle of the afternoon, the boys lost no time in packing their camp equipage and provisions on the aeroplanes. In order to find a suitable place for a camp lower down they might be obliged to traverse considerable country.

In describing this part of the continent a traveler once crumpled a sheet of paper in his hand and tossed it on the table, saying to a friend as he did so that that was an outline map of the northern part of South America. There were many gorges and plateaus, but only a few spots where aeroplanes might land with safety.

After quite a long flight, during which the machines soared around cliffs and slid into valleys and gorges, the boys found a green valley watered by the Esmeraldas river. Here they dropped down, and the shelter-tents were soon ready for occupancy.

“I suppose,” Carl grumbled as provisions were taken from the flying machines and brought to the vicinity of the fire, “that we’ll have to fight thousands of kinds of crawling and creeping things before morning!”

“Well,” Jimmie laughed, “you wouldn’t stay up there where the flying and creeping things don’t live!”

“My private opinion,” declared Glenn, “is that we ought to spend most of our time in the air! I wish we could sleep on the machines!”

“Where are we going, anyhow?” demanded Jimmie.

“We’re going to follow the backbone of the South American continent clear to Cape Horn!” replied Ben. “That is, if our flying machines and our tempers hold out!”

“I have an idea,” Glenn said, “that we’ll spend most of the time in Peru, which is probably the oldest country in the world so far as civilization is concerned.”

“That’s another dream!” exclaimed Carl.

“Look here,” Glenn exclaimed, “there are still temples and palaces in Peru which date back beyond the remotest reach of tradition. The earliest Incas believed that many of the fortresses, castles and temples which they found there were formed by the gods when the world was made.”

“That’s going back a long ways!” laughed Jimmie.

“There’s a lake in Peru called Titicaca on an island in the middle of which lies an ancient palace and many other structures,” Glenn went on. “Gathered about it are the remains of a civilization that was old when the people of Europe consisted of a group of semi-heathen tribes wandering from place to place. There are