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[Illustration: _The Andes looked dark and forbidding._]


SECRETS OF THE ANDES

by

JAMES FOSTER







The Saalfield Publishing Company
Akron, Ohio      New York

Copyright, MCMXXXIII
The Saalfield Publishing Company

Printed in the United States of America


      *      *      *      *      *      *

    THE EXPLORATION SERIES
    BY JAMES FOSTER
    CAPTURED BY THE ARABS
    LOST IN THE WILDS OF BRAZIL
    SECRETS OF THE ANDES
    THE FOREST OF MYSTERY

      *      *      *      *      *      *



CONTENTS


    CHAPTER                                   PAGE
         I Stranded                              1
        II The Aimless Wanderer                  9
       III Helplessly Trapped                   17
        IV The Surly Trainman                   28
         V As Guests of the Naturalist          37
        VI The Big Surprise                     42
       VII Off for the Andes                    48
      VIII Caught in the Storm                  62
        IX A Fearful Discovery                  69
         X Train Robbers!                       75
        XI Chubby the Eater                     82
       XII The Pangs of _Soroche_               93
      XIII A Happy Reunion                     101
       XIV An Unexpected Displeasure           109
        XV Attacked by Indians                 118
       XVI Just in Time                        126
      XVII The Old Man's Tale                  133
     XVIII Starting Into the Mountains         140
       XIX A Terrible Sight                    148
        XX Difficulties of the Trail           158
       XXI Danger at Hand                      169
      XXII The Deadly Snake                    180
     XXIII Descending Rapidly                  186
      XXIV The Big Secret                      199
       XXV Another Hidden Wonder               207
      XXVI A Narrow Escape                     214
     XXVII Fighting Desperately                222
    XXVIII Almost a Tragedy                    230
      XXIX The Horrible Beast                  239




CHAPTER I

Stranded


"Look! The bridge is out! Stop the car--quick!" Bob Holton's voice was
unsteady as he gazed ahead at the place of danger.

Acting on the instant, Joe Lewis pushed the brake pedal to the floor
and waited breathlessly, his mind filled with thoughts of tragedy.

The wheels of the small automobile locked, but the momentum carried
the car on at a sickening pace. Despite the fact that the tires were
new, they slipped over the road easily.

An instant later the youths saw that the distance between themselves
and the washout was not great enough. In but a few seconds they would
be plunging down the embankment into the swollen river.

There was not a moment to lose. Opening the doors as rapidly as
possible, the chums jumped from the car and rolled over on the ground,
their faces wet with perspiration.

And they were none too soon. The car sped on, reached the edge of the
river bank, and then plunged out of sight.

There was a loud splash as it struck the water, and then all was
quiet. The sun continued on its downward path, the faint wind played
through the trees. Nothing but two lone boys were left to tell of the
misfortune.

"Well," sighed Joe, at last breaking the silence, "we sure had a tough
break, didn't we?"

"Lucky to get off with our lives, though," Bob reminded him. "That was
about the closest shave I've ever had. Wonder why the highway
commission didn't put out a sign?"

"Probably didn't know the bridge was out. Not many cars go over this
road, and it would not be exceptional for this to go unnoticed for
quite a while."

"We'll sure make a report of it," said Bob, getting to his feet and
brushing off his mud-stained trousers.

Joe laughed unwillingly.

"That'll be like locking the barn after the horse has been stolen," he
grunted. "Come on," he went on, "let's go over to the river bank and
see if we can catch a glimpse of the coupé."

The youths walked over and stared into the swiftly moving water. It
had rained in torrents two days before, and the river was now almost
a rapids.

"Car's nowhere in sight," said Joe Lewis gloomily. "But"--his face
lighting suddenly--"it's insured. So I guess there's no use worrying."

"Maybe not about the automobile. But how are we going to get back to
Washington?"

"We'll have to hike to the main highway, I guess," Joe answered. "It's
about five miles away, too."

The youths were returning to their homes in Washington, D. C., after
having spent a delightful week-end in Virginia. Their accident came
upon them in a rather out-of-the-way spot, a great number of miles
from the city of their destination.

"If it hadn't been for that hill," remarked Joe, as he and his friend
walked back up the road, "we would have seen this place in time to
stop the car."

"The hill is here, though," returned Bob with a grim smile. "So that's
that."

The boys paused a moment at the spot where they had jumped from the
doomed automobile. With one last look at the washout, they turned and
began climbing the grade.

"Five miles is a good distance to walk," grunted Joe, "especially when
we want to get home before long."

"That last you said made the first all right," laughed Bob Holton,
"because on the Sahara and in Brazil we often hiked, not five miles,
but several times that far without stopping."

The friends were refreshed after the idle weekend trip and worked
their legs like pistons. Despite their serious predicament, they
observed the wonders of autumn with the eye of a nature lover.

Leaves of yellow and brown were lying about the ground in profusion,
while others on the trees were almost ready to fall. There was a cool
afternoon breeze that gave evidence of winter being not far off.

"Think there's a chance of getting a ride with somebody?" asked Joe,
as the youths followed the curving road.

Bob shook his head.

"Fellows in this part of the country are pretty careful about picking
up strangers," he returned. "Too many stick-ups and robberies. Still
we might see some soft-hearted person who would not be afraid to take
a chance with us."

"The question is, though," began Joe, "will we get in with somebody
before night? It's three o'clock now, and we may have to do a great
deal of thumbing before anybody will stop and let us in."

The road wound through a rather isolated section, with only an
occasional farmhouse looming up from behind the trees. It was indeed
a poor place to be stranded.

The sun was well down to the horizon when the youths finally reached
the through highway. Although they had done their best, they had found
it difficult to avoid the many large mud puddles that often reached
nearly across the road.

"Now to get down to business," said Bob, gazing far down the highway.
"We'll surely find a car before long that will pick us up."

"Here comes one now," observed Joe. "It'll be here before long. Come
on, let's get out farther."

The boys waited for the automobile to come nearer. Then they signaled
the driver. But the latter appeared to pay no attention to the young
men. A moment later the car whizzed on up the road.

Bob and Joe looked at each other. Their faces clearly showed that they
expected the worst.

"Could hardly blame him, though," remarked Bob. "So many
innocent-faced crooks walk the highways that it's unsafe to pick up
anyone."

"But you know the old proverb," grinned the other youth. "'If at first
you don't succeed, try, try again.' According to that, we---- Look!
Here comes another car. Maybe we'll have better luck this time."

Again the chums signaled, and were delighted to see that the car was
coming to a stop. At a motion from the driver, who was the only
occupant, they climbed inside.

"How far ye goin'?" the stranger asked. He was a short, fat man who
looked capable of great mirth.

"To Washington," replied Bob. "We had an accident with our car not far
from here."

"Accident, hey? Not hurt, I hope?"

"No. We were able to jump out in time. You see, we came unexpectedly
on a spot where the bridge was washed away. Caused by the recent rain,
no doubt."

"Oh. Tough luck, wasn't it? And the machine--was it insured?"

"Luckily it was," replied Joe with a chuckle. "Though we may have
trouble in proving it."

"Fight it to the finish!" said the man, shifting his cud of tobacco to
the other side of his mouth. "If you have to, take it to court."

"I hardly think that will be necessary," Joe said with a smile. "The
insurance company bears a good name."

"Wonder if this guy's Scotch?" mused Bob to himself. Only recently the
youth had read a good joke about a man of that nationality.

For the next half-hour the three carried on a varied conversation. It
was at last broken as they neared a small town.

They had almost entered the city limits when a slowly moving freight
train halted them. Reluctantly they settled back and waited.

"This will mean a big loss of time," remarked Joe, as he gazed far
down the track at the seemingly endless string of cars. "I'm anxious
to----"

"Listen!" commanded Bob, leaning forward wonderingly. "Did you hear
anything? There it is again."

"It's a muffled cry for help, coming from one of those freight cars."
Joe had opened the door of the sedan.

With a parting word for the driver, the youths left the automobile and
ran down the track, straining their ears for a repetition of the cry.

"There it is again!" declared Joe. "Sounds like a young boy. In that
third freight car up there."

Summoning all their strength, the youths ran on until they were
opposite the box car. It was easy to keep abreast with the train,
moving as slowly as it was.

The door was pushed back about three feet, leaving barely enough room
for the youths to clamber up into the car. Their efforts were not in
vain, however, and soon they found themselves inside.

"Where are you?" called Joe, glancing about at the scores of boxes and
barrels.

"Here!" a faint reply came from a far corner.

At once the youths turned in that direction, searching for a
passageway between the many objects that filled the car. At last they
were within a few feet of the corner. But it was not possible to
penetrate farther, for a large pile of heavy crates barred the way.

"Let's get these to one side," said Bob, and for the next few minutes
the young men worked furiously.

Finally they made an opening sufficient for them to pass through.

"Now we'll see who's here," muttered Joe Lewis.

The youths worked their way through the passage, their eyes trying to
pierce the darkness.

Suddenly they drew back with a cry of surprise.




CHAPTER II

The Aimless Wanderer


Emerging from behind a pile of boxes was a small boy, his face black
with dirt that looked the product of weeks. The clothes he wore were
soiled and torn, and his shoes barely clung to his feet.

"Thanks!" was all he said, as he glanced up shyly at Bob and Joe.

For several seconds the young men stared wonderingly at this forlorn
being, as if trying to account for his presence. Finally Bob broke the
silence.

"What's it all about?" he asked. "What are you doing _here_?"

The boy hesitated a moment, looked up at Bob and Joe, and then,
satisfied that he could confide in them, spoke.

"I--I was caught behind that stuff," he stammered. "I hid under a pile
of bags when they loaded the car so they wouldn't find me."

"But why were you in the car?" demanded Joe. "Where are you going?"

The boy waited a moment before replying.

"I don't know," he confessed, dropping his head.

There was something about this youngster's frankness that moved the
youths to pity.

"Come," urged Bob, laying his hand on the boy's shoulder, "tell us
about it. Why did you run away from home?"

"I didn't want to go to school, that's why. Ain't that reason enough?"

"H'm. Don't like school, huh? Where do you live?"

"Chicago."

There were exclamations of surprise from Bob and Joe.

While they gaze at the young lad in wonder, it might be well, for the
benefit of those who have not read the first two books of _The
Exploration Series_, to tell something about the two youths, and what
had been their adventures up to the present time.

Bob Holton, who was generally the leader of the two, was a large,
powerful boy of nineteen. His complexion was originally light, but an
adventurous life in hot lands had made him bronzed. Wherever he went,
he was a prime favorite of all.

Joe Lewis was Bob's closest friend, the two being almost inseparable.
Joe was of medium build and possessed many desirable characteristics.
But in a crisis he was never as cool as the other youth.

Fortune favored the boys. Their fathers, Howard Holton and Benjamin
Lewis, were noted naturalists, who often wandered to far corners of
the globe in search of wild animals for a large Washington museum. The
two families thus lived in Washington, their homes being but a few
rods apart.

Shortly after Bob and Joe had graduated from high school, they were
given an opportunity of accompanying their fathers to little-known
Brazil. Here with wild animals and treacherous savages they had many
thrilling adventures, which are related in the first volume of this
series, _Lost in the Wilds of Brazil_. The boys proved themselves
worthy of being called explorers, and the following spring were given
another chance to penetrate the unknown.

On the Sahara Desert they encountered more perils and hardships. How,
among other things, they endured a terrible sand storm, went for days
without water, and finally fought hostile Arabs for freedom, is
related in the volume entitled _Captured by the Arabs_.

At the time this story opens, the youths would have been in college
had it not been for another proposed scientific trip. The naturalists
had finally decided to explore the Andes Mountains in South America,
and Bob and Joe were given the permission to accompany the men. The
boys had argued stiffly that such an adventure would benefit them as
much as a half-year at college, to which their fathers had finally
agreed. Now less than two weeks remained before the expedition would
depart.

As we return to Bob and Joe, who stood staring in amazement at the
small lad who said his home was in Chicago, we see that Bob is
speaking.

"And you came all this distance?" he asked. "How old are you?"

"Twelve."

"Aren't you sorry you ran away from home?" queried Joe.

"I ain't sorry, but I'm goin' back. That's where I'm headin' now."

"Why did you change your mind?" Bob asked.

"Even school's better'n goin' without anything to eat," the boy said.

For some time Bob and Joe sat staring at the floor. Everything was
clear to them now. They were impressed by this little fellow's
resourcefulness in finding his way freely about.

Suddenly Joe glanced up. He had almost forgotten that he was on a
moving freight train. The cold sweat burst out on his forehead as he
saw that they were now traveling rapidly.

"No chance of getting off now, Bob. I guess we're in for it. Where
does this train go?" he asked the boy.

"Chicago," was the response. "That's where this car is headed for. I
made sure before I got in it."

Bob grunted.

"We're booked for a ride, I guess," he said. "Still there may be a
chance of getting off at some town not far from here."

"That's what we'll hope for," the other youth said, nodding. He turned
to the lad. "Can you find your way home after you reach Chicago?"

"Sure. This ain't the first time I've run away. Gettin' back ain't
what worries me."

"What does?" inquired Joe.

"My old man. He'll be mad enough to bite nails. Bet he's got the razor
strop hangin' up now waitin' for me."

Bob and Joe smiled. The personality of this waif touched them.

"Bob Holton is my name, and this is my friend, Joe Lewis."

A small hand was extended.

"I'm Spike Weaver, the son of a horse thief."

The youths burst out in laughter.

"A horse thief?"

"Yes," the boy said. "That's what the old man used to be. I'm not onto
him now, I been away from home so much."

Another outburst of laughter followed. The youths were beginning to
take a liking to this small wanderer.

One thing stood out in the young men's minds: the family to which this
boy belonged was evidently of a very low type morally. Little wonder
that young Spike had turned out to be a worthless ne'er-do-well. There
was apparently little hope for his future.

"Why don't you go to school and try to make something out of
yourself?" asked Bob. "Wouldn't you like to be a big business man, or
doctor, or merchant, or _naturalist_?"

"What's that?" the lad asked.

"A naturalist is a scientist who travels to little-known places to
collect wild animals for a museum or college," explained Bob.

There was a glint of interest in young Spike's eyes. He had absorbed
this definition eagerly.

"Does he shoot with a big rifle, and camp out?" Spike demanded.

"That's exactly what he does," Bob replied. "And he usually has plenty
of adventures, too."

"Boy! That sounds swell! Wonder what it feels like to fire one of them
guns."

"Feels all right after you get used to it," Joe said.

"How do you know?" Spike asked, as though he felt that Joe was
talking of something that he knew nothing about.

"My friend has fired them," explained Bob. "And so have I."

At once the lad was all excitement.

"You've really hunted wild animals? Tell me about it."

During the next hour Bob and Joe related some of their experiences in
Brazil and North Africa, while their newly made young friend listened
breathlessly. By the expressions on his face they knew that he was
absorbing every word with interest. When they had finished, his
admiration for them was beyond expression.

"Gee! You two are real naturalists," he said.

"Not yet," corrected Bob, "though we hope to be some day. To be a
naturalist you must go through college and get your lessons every day.
But it isn't hard if you want to like it."

For a time young Spike seemed lost in thought. Finally he roused
himself and turned to his friends.

"I'm goin' home and go to school, so I can be a naturalist," he said
conclusively. "And then maybe I can have a lot of fun huntin' and
campin', like you fellows do. I always did want to do that."

Bob and Joe glanced at each other. Did this lad's decision mean
anything, or was it merely a childish notion? At least they had
induced him to attend school temporarily.

Joe started to speak, but Spike silenced him.

"Look!" he cried. "We're comin' to a stop. This must be a town."

The boy was right. The train was gradually slowing up at a spot where
the track had branched into several switches. At last it came to a
full stop.

"Now's our chance to get off," declared Joe. "We----"

"Keep still," hissed Bob. "Somebody's coming down the track. It may be
a railroad policeman, or 'bull,' as the hoboes call them."

"Let's hide behind these boxes," suggested Joe. "He may be coming in
here."

Quickly, yet quietly, the three concealed themselves in a corner of
the box car. Then they waited.

The sound of someone walking grew louder, and the next moment a man
stopped at the side of the box car. There was the sound of a door
rolling forward, and then the click of a chain. Less than a minute
later he was on his way up the tracks.

Hastily the hideaways slipped out from behind the boxes and into the
center of the car.

Bob uttered an exclamation of dismay.

"That fellow locked the door!" he cried. "We're trapped!"




CHAPTER III

Helplessly Trapped


Spike uttered a cry of fright, while Joe dashed forward to make sure
that his friend was right.

As Bob had said, the railroad man had fastened the door securely.
There was an opening of about eight inches, across which was a heavy
chain that terminated at a large lock. In order to cut the chain, a
file would be necessary.

Of the three prisoners, Spike was the first to resume his natural
attitude. Perhaps this was due to his wide experience in riding
freight trains. At any rate he seemed to forget his plight and resign
himself over to any fate.

"Tough luck!" the lad said. "Guess you guys will have to ride with me
to Chicago. May be several days before we can get anything to eat,
too."

"That's the worst part about it," lamented Bob. "It may be days, or
even weeks, before we'll reach our destination."

Bob and Joe were inclined to be downhearted, but their young friend
was cheerful.

"Don't you worry," he consoled them. "I've been in tight fixes like
this many a time, and I've always got out all right. One time I went
out West and got locked in just like we are now."

Young Spike sounded like an experienced vagabond, and the youths could
not help laughing.

"How did you get out?" asked Joe, after the laugh had subsided.

"It was easy. When we stopped at a town I just waited for some hobo to
come along. Somehow he got ahold of a file and had me out in a jiffy.
Hoboes are good to do anything like that for you."

"Let's hope history will repeat itself," muttered Bob, who, along with
Joe, did not like the prospects of a trip to Chicago.

Less than ten minutes later there was a slight jar, and the train
started moving. Although pulled by a large engine, there was little
chance of high speed, for a line of cars over a half-mile long
stretched far down the track.

Bob, Joe, and Spike crowded before the crack to catch a glimpse of the
town at which they had stopped. But aside from a number of freight
cars and old buildings, there was little to be seen.

"Suppose we arrange boxes in front of what little opening there is,"
suggested Joe. "We may as well amuse ourselves by looking out."

"That reminds me," burst out Spike. "I want to see if anything in this
car has stuff to eat in it."

He at once began a search of the many boxes, bales, and crates that
were packed in each end of the car. Suddenly he gave a cry of delight.

"Here's apples!" he cried excitedly. "Gee whiz! Who says we don't
eat?"

But the fruit was in tightly nailed crates, which could not be easily
opened.

"Come here, fellows!" shouted Spike. "Give me a hand! You don't expect
_me_ to open 'em when there's big guys like you around, do you?"

"Wait a minute!" commanded Bob. "Whose apples are they?"

"Whose are they? I don't know. Why?"

"Do you think it's right to get in a box car and eat up somebody's
apples?"

"Ah, gee whiz! You ain't gonna back out of a chance like this, are
you? Come on. Be a sport."

Bob stoutly refused.

"We're not going to open any boxes or crates around here, and you're
not either! Get that and get it straight! Of course if we have to, to
keep from starving, we will. But not now."

Against this stout protest there was no use persisting, and Spike
finally walked sullenly back to his seat before the slightly open
door.

"You guys sure are the berries," he said with an ironic smile.
"You'll never get anywhere that way."

"That's where you're wrong," Joe corrected him. "We will and you
won't, unless you get such notions out of your head."

"Ah, blooey!"

A half-hour of silence followed, during which time the three gazed
absently out, watching the farms, the forests, the rivers and creeks
slip by. They were beginning to enter the Appalachian Mountains, and
more of natural beauty promised to be visible.

But Bob and Joe did not care to observe the beauties of nature just
then. Their thoughts were dwelling on the probabilities of the future.
What lay in store for them? Would they be able to get home in time to
accompany their fathers to the Andes Mountains, or would fate rule
that they remain for an indefinite period in this box car? If the
truth were known, the youths were not a little worried.

Darkness was beginning to enshroud the travelers, and the necessity of
making improvised beds moved them to action. There was a large pile of
burlap sacks in a far corner of the car. These they arranged a short
distance from the partly open door.

"I don't think these bags are inhabited," smiled Joe. "They look
almost brand-new. At any rate we'll take a chance with them."

"We'll have to," agreed Bob, who realized the necessity of a rest
after such an arduous day.

However, the travelers spent an hour or so longer gazing out at the
dim outlines of the mountains. Although Bob and Joe were tired, they
had an uneasy feeling about resigning themselves over to sleep.
Something unexpected might happen during the night.

Finally Bob arose and walked over to his bunk.

"Suppose we turn in," he suggested. "We may need plenty of energy
tomorrow. It's possible for almost anything to happen, you know."

Joe nodded and took his place beside his friend, but Spike announced
that he would remain up awhile longer.

Almost at once the youths fell asleep. But from their experiences in
dangerous lands they had learned to keep one eye open as a precaution.

This proved to be unnecessary, however, and they awoke the next
morning greatly refreshed.

"We're on the other side of the mountains," observed Joe, as he
stretched and glanced out of the crack.

"Now maybe we can make better time," Bob said, moving over to the
door.

The three travelers were forced to begin the day without breakfast.
Spike insisted that they open the crates of apples, but Bob firmly
refused.

"We may find some way out today," the youth consoled him. "If we have
to, we can eat a few of those apples tonight."

All morning the train continued on its journey, passing small towns
and villages. Along toward noon it stopped at Charleston, West
Virginia, where after an hour of switching it was left on a side
track.

Suddenly Joe, who was standing by the crack, caught sight of a
trainman not far away. The man's face was rather pleasant, with no
trace of gruffness.

"There's a chance," Joe said. "Let's ask him to help us out."

"No, don't," pleaded Spike, pulling Joe back.

"Why not?"

"'Cause if he gets you out he won't let me keep in this car to
Chicago."

"But what about Bob and me? We don't want to ride all that distance."

"No. Go ahead and call him," directed Bob, who was moving up to the
door. "Spike can find another car that's going to Chicago. We want to
get home."

Disregarding the lad's protest, Joe shouted and motioned for the man
to come to the box car. There was a look of surprise on the fellow's
face as he moved over to where the three were trapped.

"What's it all about?" he demanded. "You guys trying to steal a ride,
huh? Come on out of there and pick a car that ain't got anything in
it."

"We can't get out," explained Joe. "Locked in, I guess. That's what we
wanted of you. See if you can get the door open."

"Oh! So they penned you up, huh? Yeah. I see that locked chain now.
Sorry, but I'm afraid I can't do anything for you."

"But--but we've got to get out," Joe said persistently. "We haven't
had anything to eat for quite a while."

The man hesitated a moment.

"Got any money?" he asked.

"Yes."

"Let's see it."

Joe held up a half-dollar.

"O.K. There's a grocery a block from here. Want me to get you
something?"

Delighted at such a chance, Joe instructed the trainman to purchase
several articles of food that would be sufficient to last for several
days. It was with a feeling of high hope that the youths watched the
man walk in the direction of the store.

In less than fifteen minutes he was back and handed Joe a sack of
groceries in return for money. In recognition for his service, the
youth tipped him generously.

"Now for a delicious meal," said Bob, smacking his lips. "And will we
eat!"

The boys _did_ eat, and felt much better for it. When they had scraped
up the last crumb, they stretched out on the burlap sacks.

The remainder of the day passed without incident. Darkness was just
setting in when, with a slight jerk, the train started moving.

Even though they had expected an undisturbed sleep, Bob and Joe were
delighted that they were again on their way. Every mile left behind
would mean that they were nearer Chicago, which was perhaps the only
city at which they could hope to escape from their prison.

"Let's hope we make good time now," breathed Bob, as he and his
friends turned in, to get what sleep a rumbling train would allow
them.

All through the night the freight rattled on, this time much faster
than before. Although several stops were made, the train made
unusually good time, pulling into Cincinnati late the next morning.

"Here's where we'll have to wait," said Joe. "They might keep us
switched here for several days."

Almost at once their box car was sidetracked, and was not moved until
late the next day. About four o'clock another engine was attached, a
much shorter train being formed. Then slowly it pulled off the switch
and found a through track.

Bob and Joe could hardly believe their eyes. Were they to leave
Cincinnati so soon?

An hour later this question was answered. The boys found themselves
speeding along to Chicago, after having remained on the switch less
than twenty-four hours.

"I suppose we'll stop at every town and small city in Indiana," said
Bob gloomily. "Even though this is a fast freight, a delay will be
almost inevitable."

The youth was right. It was nearly three days later when the train
entered the city limits of Chicago. Gary and other cities of the
Calumet district had been left behind.

After what seemed like hours of constant travel in the metropolis, the
freight stopped at a busy switch yard, where scores of trains were
moving in all directions.

Suddenly Bob cried out in delight as he caught sight of a man walking
up the track. The youth recognized this fellow as the one who had
snapped the lock on the box-car door, making the young men and Spike
prisoners on the train.

Bob at once called the man, who, upon hearing, turned about in
surprise.

"Why--what--what are you doing in that car?" he demanded angrily, as
he caught sight of the youth.

"We want to get out!" Bob's voice was cool and determined.

"But how did you get in there? I thought I locked that door. I----"

"Let us out and we'll tell you all about it," Bob pleaded.

The man pulled a bunch of keys out of his pocket and immediately
unlocked the door. Bob hurriedly rolled it open and jumped out,
followed by Joe and young Spike.

It was good to feel their feet on the ground again. Bob and Joe could
have cried out in joy. But there was little time to do this, for the
trainman demanded an explanation of their presence.

Briefly Bob narrated the circumstances that led to their boarding the
train, shielding Spike as much as possible. When he had finished, the
man viewed the young lad critically.

"I think I'll turn you over to the yard master," he said to Spike,
"and see that you get what's coming to you."

He roughly caught hold of the boy's arm and pulled him forward.

"Wait a minute," begged Joe. "Spike didn't do any harm. He's promised
to quit running around and go home and go to school."

"Well, he ain't gonna get no sympathy from me. I got no use for a kid
that rides freights."

He gave the boy another pull, this time so violent that the latter
slipped and fell, bruising his face on the cinders.

Bob grew furiously angry. He stepped boldly up to the trainman.

"Let the boy alone!" he demanded, his eyes seeming to penetrate the
man.




CHAPTER IV

The Surly Trainman


Before the blaze in Bob's eyes the man shrank back, hesitated a
moment, and then turned in the direction of the freight station.

"All right," he snarled. "But don't let me catch the kid around here
again, or you either."

He walked up the track to the end of the train, then disappeared
behind the engine.

"Gee, that was swell of you," said Spike to Bob. "You sure had that
guy scared."

"He was glad enough to get out of it," laughed Joe. "Old Bob wouldn't
have left a grease spot of him."

"But now," began Bob, anxious to turn this tribute aside, "let's
figure out what to do. I suppose the only thing----"

"I want to get home," Spike interrupted. "I may have something comin'
to me, but the sooner I get it over, the better."

"Where do you live?" Joe asked.

"Only about a half-mile from here."

Joe got a piece of paper and pencil out of his pocket. He tore off one
corner and wrote down the address of himself and his friend. This he
gave to Spike.

"Here," he said. "Write us a letter some time. Now where do you live?"

Spike told him, and then, with a warm good-bye, he left the youths and
hurried down the track.

Bob and Joe watched the lad until he disappeared from view. Even after
they lost sight of him, they stood gazing in that direction until a
locomotive whistle roused them.

"He's a good kid, all right," smiled Bob. "Might be an aimless
wanderer, but he has a lot in him."

"Got a keen sense of humor, too," said Joe, and then added: "I wonder
if he'll really go to school and make something out of himself, as he
said he would?"

"Hard telling. A lot can happen to change his mind, you know."

For several minutes Bob and Joe watched the busy scene about the
tracks. Finally a factory whistle from afar prompted Joe to glance at
his watch.

"Nearly two o'clock," he announced. "Come on. Let's hurry down to the
freight station and see if we can send a telegram to our folks. If we
hadn't lost the car in that river, we would have been home several
days ago."

The youths moved down to the building and went inside. After making
several inquiries they finally found the main office, where they were
permitted to send a telegram. Then they left the building and walked
in the direction of the street.

"Good old Chicago," smiled Joe. "It's only been a couple of months
since we were here."

Bob stopped suddenly.

"That reminds me," he started. "We came here with our dads to see a
Mr. Wallace, who's with the Museum of Natural History, didn't we? And
this Mr. Wallace is planning on going with our dads' expedition to the
Andes Mountains, isn't he? Do you suppose he's left for Washington
yet?"

Joe's face lightened.

"I see what you mean," he said. "We can go and see him, and
incidentally we can borrow enough money to get home on. Suppose we go
to the museum now."

The boys were familiar with Chicago and had no difficulty in taking a
street car. After a half-hour's ride they got off within a few squares
of the museum. A ten-minute walk brought them to the main entrance.

At the office they made inquiries about Mr. Wallace and finally found
him in a laboratory on the second floor. He smiled broadly as he
recognized Bob and Joe.

"Well, this is an unexpected pleasure," he said, extending his hand.
"What, may I ask, are you fellows doing in Chicago? Why aren't you
getting ready for that Andes expedition?"

"It isn't our fault that we're here," laughed Bob, and then proceeded
to tell of the events that led to their presence. "Since we finally
landed here, we thought we'd come to the museum and see if you had
left for Washington yet," he concluded.

"A strange chain of circumstances," the scientist breathed. "Not many
could go through all that in the course of a few days. No doubt it was
your first experience as hoboes, was it not?"

"First and last," returned Joe. "We've had all we want of it. But
now," he went on, "when are you going to Washington? The expedition
leaves in little more than a week."

"I had planned to go day after tomorrow," Mr. Wallace said. "I think
everything will be in readiness by that time. I'd like to spend at
least three days in Washington talking with your fathers and others of
the expedition before sailing. Of course you fellows are familiar with
the details of the expedition, are you not?"

"Quite the contrary," returned Bob. "You see, when the matter was
first mentioned, about a month ago, there was not much known about
it. Our dads declined to say much, because they were not absolutely
sure they were going. Joe and I, though, had a sort of feeling that
they _were_ going, and finally got permission to stay out of college
at least a half-year."

"So you could go with the expedition?" interrupted the scientist.

Bob nodded.

"We figured we'd get as much good out of such a trip as we could get
in a university," he explained. "Then, too, there's a chance of making
money by taking motion pictures, as we did on our other expeditions."

"I think you did wisely," Mr. Wallace said. "It usually isn't good for
a fellow to get out of college too young. When an extraordinary chance
like this turns up, it's best to take it."

He motioned for the boys to follow him into his office, where several
chairs were arranged about the desk. A large bookcase occupied a whole
end of the room, while opposite it was a case of instruments and
preservatives.

"Sit down," he directed them, "and we'll talk over this Peruvian
expedition."

Bob and Joe did as directed, glad of the chance to rest their tired
limbs.

Mr. Wallace procured an atlas, opened it to a map of Peru, and drew
an imaginary line in the lower right-hand corner.

"Here's Cuzco," he pointed out. "We'll probably make it or some other
near-by city our base. From there we'll go into the Andes Mountains on
our varied scientific quests."

"But what--what is the main purpose of the expedition?" inquired Joe.
"Of course, you and Mr. Holton and Dad are naturalists, who want to
get specimens of animal life. But that isn't the chief aim of the
expedition, is it?"

"No. It is being sent out by the division of ethnology at the museum
in Washington. The scientists in that field have in mind mainly to
study the ruins of the vanished Inca civilization. Those Indians, you
know, that built so many marvelous works of architecture. That's about
as much as I know about them, though," he laughed. "My line runs
straight through the field of natural history and zoölogy, and
incidentally anatomy, histology, taxonomy, embryology, ecology----"

"That's enough!" interrupted Bob, smiling sheepishly. "You don't
expect Joe and me to be acquainted with all those subjects, do you?
We're pretty good shots, but as scientists we're as yet a complete
flop."

A general laugh ensued, after which the naturalist again pointed to
the map.

"We are to explore the region northwest of Lake Titicaca," he
continued. "I understand there are some very high peaks in this range,
all the way from ten to twenty thousand feet in altitude."

"These Incas," started Joe, "when did they live? It hasn't been so
very long ago, has it?"

"Not as time is usually thought of. The sixteenth century witnessed
their downfall. This was at the time of the Spanish South American
explorations, you know."

"Those Spaniards sure saw something unusual and unexpected," remarked
Bob. "This mountainous region was chock-full of architectural wonders,
all built by the Incas."

"Something tells me we'll see sights, all right," said Joe. "It will
be good to get away from home again--into the unknown, I mean. And
that reminds me. Would it be possible for you to lend us enough money
to get back to Washington?"

"Why--of course. How much do you need?"

"Fifty dollars will pull us through. Perhaps we can get along on less
than that," was the answer from Bob.

"All right. I'll see that you get it. But wait! I expect to go day
after tomorrow with a friend, who is driving East on business. There
will be plenty of room for two more. You fellows don't have to get
home at once, do you?"

"No, we don't have to," returned Joe. "We----"

"Suppose you be my guests until then. I'll be only too glad to have
you. In the meantime we can be discussing the coming expedition."

"We'd sort of hate to do that," Bob said. "It will mean a lot of
trouble to you."

"Forget it! I'll be only too glad to have you."

"Well, all right, if you----" Joe began.

"We'll call it settled," Mr. Wallace said. "And now, since my day is
practically over, we may as well go to the house. That is, if you're
ready."

"We're ready any time," Bob told him.

The three went outside, to a place where the naturalist's automobile
was parked. All got inside and drove through the city till they came
to a beautiful suburb.

"Here's my place," said Mr. Wallace, pointing to a large house of
rather costly design.

Inside, the youths were introduced to Mrs. Wallace, who made them feel
perfectly at home.

"I hate to see Mr. Wallace leave on an expedition," she said, "but I
can appreciate his interest in science. In fact, I have often wished I
could accompany him. Be a sort of Mrs. Martin Johnson, you know."

"I wish our mothers were like that," laughed Bob. "If they were,
perhaps Joe and I wouldn't have so much difficulty in getting their
consent to go with our dads."

A bountiful dinner was soon served, Bob and Joe eating heartily.

"And now I have a surprise for you," Mr. Wallace said, when the meal
was over. "It is something I know we all will enjoy, especially in
view of what is to come."

The young men looked inquiring.




CHAPTER V

As Guests of the Naturalist


"What is the surprise?" inquired Joe Lewis anxiously.

"This: I made arrangements for a movie to be shown--purely for our own
benefit," the naturalist explained. "It deals with Peru and the
Andes."

"The region we're going to explore!" cried Joe, delighted beyond
words. "Why, that will be wonderful!"

"I've never seen it," Mr. Wallace said. "But the chances are it will
be good. Perhaps we had better go before long. It is to be shown at
eight o'clock, and we haven't a great deal of time to get down there."

"Where?" inquired Bob.

"To the museum--in the auditorium," was the response.

Mrs. Wallace asked that she be permitted to go also, and the others
consented at once. The wonderful civilization of the ancient Inca
Indians she knew not a little about.

At the museum they found several score people waiting for the movie to
be shown. There was a friendly gathering for a half-hour or so, at
which Mr. Wallace introduced a number of scientist friends from the
museum and Chicago universities.

Then the lights were switched off and the movie was projected. It
proved everything and more that Bob and Joe had expected, showing the
fascinating country of Peru.

The shy Indians with their flat "pancake" hats, the curious llamas and
alpacas, the magnificent heights of the mighty Andes, the many old
ruins of the Incas--all these and more were depicted on the screen.

It was very inspiring, especially to the boys and Mr. Wallace, who
were delighted that before long they would be able actually to visit
those wonderful places.

During the drive home the naturalist's conversation was directed
chiefly about this inspiring country, his excitement being almost like
that of a small boy. But if the naturalist was impressed, the youths
were still more. They longed for the great day to come when they would
leave for the wonderland of Peru.

It was so late when they arrived at the Wallace residence that the
youths and their hosts decided to retire at once.

"I'm not going to the museum today," announced the naturalist the next
morning at breakfast. "There is so much that has to be done in the way
of preparing for the coming expedition that I won't have time for
anything else."

"If there's anything Joe and I can do for you, we'll be glad to do
it," said Bob. "Our preparations won't begin until we get back to
Washington."

The young men proved to be of valuable service to the scientist. Their
previous experience in preparing for exploration ventures enabled them
to offer valuable suggestions to Mr. Wallace, even though the latter
had made numerous trips for the good of science.

The vast resources of the great metropolis enabled them to find
anything that the naturalist needed in the way of outdoor equipment.
All that day and half of the next were spent in the business district.

"Now if you fellows like sport, as I do, what do you say about a
little target practice?" Mr. Wallace asked them, after the noon lunch.

"What do we say?" Joe was overjoyed. "Lead us to it!"

In the extreme rear of the lawn was a large rifle range. Here, with
the guns that Mr. Wallace generously furnished, they took turns
exercising their skill at the trigger. Bob easily placed himself above
the others by striking the very heart of the bull's-eye.

"I thought I was a fair shot," smiled the scientist. "But you have me
beat by a mile."

"Just happened that I hit it, I guess," Bob said modestly.

But when he again was able to send a bullet almost directly over the
first one, the others knew that it did not just happen.

"Wonderful to be such a shot," remarked Mr. Wallace. "I suppose it has
been the secret of your emerging unharmed from the unknown, hasn't
it?" he said laughing.

"Trying to kid me, are you?" smiled Bob. "Joe and I may be green, but
another expedition or two will make us full-fledged explorers. At
least we hope so."

Mr. Wallace grinned.

"That's what we all think," he said. "But the fact is, we never do get
to be what you call full-fledged explorers. I've been on a good many
expeditions, but I don't know much even now. To me it's interesting
that I got my start in scout work. The Boy Scout organization is one
of the greatest on the globe."

"So did we, to a certain extent," said Bob. "Although the fact that
our dads are explorers perhaps accounted for a still earlier
interest."

The youths and the naturalist spent the better part of the afternoon
on the rifle range. Then they went to the house, where in Mr.
Wallace's extensive library they read still more about Peru and the
Andes.

That evening they spent quietly, for the next day they were to start
on the trip to Washington. The naturalist's friend, with whom they
were to drive to the East, was to come after them early the next
morning.

And early it was. Too early for the youths and Mr. Wallace, who had
barely finished breakfast. But they were packed and ready, and so lost
no time in getting their belongings together.

The friend, whose name was Wilson, was a newspaper man, often
traveling East in the interest of his profession. He was good-natured
and talkative, at once taking a liking to Bob and Joe.

When everything was in readiness, Bob and Joe and the men took their
places in Mr. Wilson's automobile and, with a warm farewell to Mrs.
Wallace, started down the driveway.

Soon the youths would be home--and on their way to the mysterious
Andes!




CHAPTER VI

The Big Surprise


As the automobile sped toward the thoroughfare, Bob and Joe settled
back for the long ride. Now that they were at last heading for
Washington, the boys were becoming impatient, although they had
enjoyed the last few days immensely.

Until after they had left Chicago, Mr. Wilson was rather quiet,
bending his efforts solely on managing the car. But when the
metropolis had disappeared from view, he inquired about his friends'
expedition into the Andes Mountains.

"Perhaps I'm not much of an adventurer, but somehow I wouldn't care
for that sort of a life," he laughed, after Mr. Wallace had related
the outlines of the expedition. "I wouldn't mind taking a trip to that
place--put up at a hotel, or the like. But when it comes to straying
off the traveled road, well----" He stopped meaningly.

Bob laughed.

"It's a good thing people aren't all alike," he said. "If they were,
either the wilds or the civilized places would be filled to capacity."

Although the youths were anxious to reach their destination, they
found the drive East interesting, even though they had made it before.
Their attention was so held by the many interesting sights that,
almost before knowing it, they found themselves in Pittsburgh, after
having eaten a lunch several hours before. In the business district
they engaged rooms in a small but comfortable hotel.

If Mr. Wilson and the naturalist were tired, the youths were not. They
insisted on taking a look at Pittsburgh, which they had not seen for
many months. An hour or two of looking around and they would return to
the hotel, remarked Bob.

During that time the young men found much to hold their interest. The
great fiery blast furnaces, the towering skyscrapers, the crowds of
pleasure seekers, and the lights of river boats all kept them gay with
amusement.

At last, when they finally made themselves return to the hotel, they
found that their friends had gone. Evidently the lure of a great city
was too much for them.

"And Mr. Wilson said he was dead tired," said Joe with a smile.

"They're no different from us," said Bob. "Want to keep on the go, I
guess."

Mr. Wallace and his friend did not return until late, much to the
amusement of the youths. Both men wore a sheepish look as they caught
sight of Bob and Joe.

"Sorry, but we just had to get out," grinned the newspaper man,
walking drowsily through the lobby. "Couldn't stand it to stay
inside."

"Perhaps you'll pay the penalty of oversleeping," laughed Joe, "and we
won't get started until late."

Joe proved wrong, however, for early the next morning they were up
making ready to resume the journey. From Pittsburgh the traveling
promised to be slower, owing to the increased traffic and mountainous
country. But Mr. Wilson was determined to make good time, and did,
reaching York, Pennsylvania, at one o'clock.

Here the youths and the naturalist were to take their leave, while the
newspaper man would continue to New York City. Had he not been in a
great hurry he would have insisted on driving them on to Washington.
As it was, his business prevented his doing so.

With a hearty farewell, the boys and Mr. Wallace left his car and made
their way to a railroad station, where they boarded a train for the
nation's capital.

An hour and a half of traveling brought them to Baltimore, and now
the youths began to feel that they were in home territory. In this
city a delay was inevitable, but at last the train resumed its journey
to Washington, which it reached in due time.

Since Mr. Wallace and the boys had not known exactly when they would
arrive, they had not expected anyone to meet them at the station. But
much to their surprise they found that Mr. Holton and Mr. Lewis were
waiting for them when they went down from the tracks.

"Boys!" cried Mr. Holton excitedly. "And there's Wallace, too. How are
you, old man?"

There followed a wild shaking of hands, patting of backs, and general
welcome, in which Mr. Wallace took as large a part as the others.

"How did you know we would come on that train?" inquired Bob
wonderingly. "Mr. Wallace didn't tell you, did he?"

"Not exactly," Mr. Lewis returned, picking up a suitcase. "But he said
you would probably get near Washington today, and that York,
Pennsylvania, would be your junction point. So Howard"--referring to
Mr. Holton--"and I called up the station to find out when the train
would get in. We were here this morning, when the early one arrived."

The newcomers were led to Mr. Holton's car, which was parked a short
distance away. Glad of the chance to relax, the youths and Mr.
Wallace threw themselves tiredly into the seats.

As mentioned previously, the respective homes of Bob and Joe were
located next door to each other, almost at the edge of the city. They
were not of costly design, but were comparatively new and pleasing.

Mr. Holton had barely brought the car to the curb when the boys'
mothers, along with Bob's small brother and Joe's sister, came out to
meet them. There followed another greeting, if anything warmer than
the first. Mr. Wallace, upon being introduced, received a hearty
welcome. It might be added that he was to remain with either the
Holtons or the Lewises until the expedition would depart for South
America.

"Now tell us what happened," urged Mrs. Lewis, Joe's mother, when
everyone had assembled in the living room of the Holton home.

Briefly Bob related the adventures of himself and his friend, from the
time they lost the car in the river to the present. He told of coming
to the washed-out bridge, of the forced abandoning of Joe's coupé, and
of boarding the freight train where Spike Weaver was trapped. The
forced ride to Chicago, the calling on Mr. Wallace, and the eventful
days that followed were described fully, while the others listened
breathlessly.

"Quite an experience," commented Mr. Holton, when his son had
finished. "Not many could have gone through it all."

The friendly gathering lasted until late that afternoon. As there was
no use making further preparations for the coming expedition, all but
Bob and Joe took it easy. The youths, however, thought it best to
notify the insurance company about losing Joe's car.

At request, the company agreed to send out an investigator without
delay. He arrived as soon as was promised and asked that Bob and Joe
accompany him to the spot where the car plunged into the river.

When they arrived at the familiar spot, Bob and Joe were not surprised
to see that workmen were repairing the washed-out bridge. The men were
aware that a car was at the river bottom.

"I'll take a few notes," said the insurance man. "Then we'll go back.
And let me assure you that this matter will be looked after promptly."

Back at their homes, Bob and Joe were surprised to see a tall young
man of perhaps twenty-five conversing with the three naturalists in
the Holton library.

Mr. Lewis looked up suddenly as he caught sight of his son and Bob.

"We've a surprise for you," he said smiling. "Part of the Andes
expedition is going by airplane."




CHAPTER VII

Off for the Andes


The surprise of Bob and Joe was almost inconceivable. They stood
staring for several seconds before either seemed to grasp the full
significance of the naturalist's words.

"Airplane? Going by airplane?" gasped Joe. "How come?"

His father laughed.

"We expected to see you fellows startled," Mr. Lewis said. "But that
you would show such unusual astonishment we did not in the least
anticipate." He turned to the stranger. "This," he went on, addressing
the youth, "is Mr. Karl Sutman, who is going to take several members
of the expedition in his airplane, or rather monoplane. Karl, I want
you to meet Bob Holton and Joe Lewis, the young men we were just
talking about."

"Glad to know you, fellows," the aviator greeted, extending a hand.

"Pleased to meet you, Mister----" Bob began, but was interrupted.

"_Karl_, if you don't mind," the tall man laughed. "I don't care for
that 'mister' stuff. First name fits me good enough."

"Good enough for us, too," said Joe with a smile. "Call us Bob and
Joe."

These informalities tended to bring about a feeling of friendliness
which was noticeable in the conversation that followed.

"Will you please explain how it all came about?" asked Bob. "This
airplane stuff almost took Joe and me off our feet."

"Off your feet you'll be in a few days," chuckled the aviator. "That
is if you ginks are picked out to go with me in the plane."

"If there's any air traveling, we want to be in on it," Bob assured
him. "But--" he hesitated a moment--"how did it all come about?"

"I'll tell you," Mr. Lewis said. "Karl's dad and I are very good
friends--have been for many years. Now when Karl learned of this
coming expedition, he at once looked me up and offered to take part of
us in his monoplane. All that he'll charge will be for the gas and
oil, and he'll pay a share of that. The fact that he is a licensed
transport pilot makes the whole thing a pretty safe venture."

"And I've had six hundred hours of flying--without a single mishap,"
Karl added proudly. "The monoplane I own is one of the fastest and
most efficient machines there are. It'll do a hundred and fifty miles
an hour with no trouble at all."

"Sounds well enough," smiled Joe. "Tell us some more."

During the next few minutes the young aviator explained in detail the
plans made for the trip. His machine, he said, could carry four
passengers and the pilot, and there was a possibility of adding one
more. Just who those passengers were to be, the others could decide.
The course they would follow he had mapped out carefully, taking into
consideration the possibility of having to land at any time. Norfolk,
Virginia, would be the last large American city they would see. From
there they would proceed south over the Bahama Islands and Cuba, and
then on to the north coast of South America. At Bogotá, Colombia, a
stop would probably be made for fuel. They would then continue along
the coast mountains (Andes) over Colombia, Ecuador, and into Peru. At
Mollendo, a small but important coast town, the air travelers would
wait to join the other members of the expedition, who would arrive
several days later by steamship.

When Karl had finished, the youths were overflowing with enthusiasm.
Their imaginations had been captivated by the prospects of a unique
air trip into the Andes. That they could accompany Karl they sincerely
hoped.

"Of course," began Joe, addressing his father, "Bob and I will be
among the passengers, will we not?"

Mr. Lewis looked grave. He did not have any too much faith in
aviation.

"We'll see," he replied. "Your mothers will have to give their
consent, you know. It may prove difficult to get that."

"I think we can bring them around," Bob said, with an optimism that he
was far from feeling, "especially if you and Dad decide to go. And you
will, won't you?"

"Impossible for me to do so," returned Mr. Lewis. "I've already made
reservations on a steamship. As for Mr. Holton, he may make
arrangements to go."

"But right now," started Karl, rising, "how would you
fellows"--referring to Bob and Joe--"like to come with me out to the
airport? I want to show you the 'plane."

"Lead us there!" cried Joe at once. "We want to take in everything."

The youths' fathers had been to the airport the previous day, and so
did not care to go again. The boys and Mr. Wallace, however, desired
to see the monoplane, especially since there was a chance of their
becoming passengers.

It was nearly noon, but the four decided to leave at once. They could
get a lunch somewhere else, perhaps at the airport.

"Besides, we're not hungry," explained Joe, when the others asked that
they leave an hour later. "Excitement and activity make us forget all
about eating."

At the airport the youths and Mr. Wallace were taken to a corner of
the field, just off the cement runway. There, before their eyes, was a
large white monoplane, shining brightly with a coat of fresh paint.

"Ain't it a dandy?" Karl was beaming all over with pride. "Just been
completely inspected. It's just r'arin' to go!"

They walked up to the machine to examine it at close quarters.

"Sure a peach for looks," commented Joe. "Got an air-cooled motor,
too. How about getting inside?"

"Go ahead. You'll find it as accommodating as a street car."

"It's all of that," agreed Bob a moment later, when he had opened the
door and stepped into the cabin. "Those comfortable deep seats appeal
to me."

"Seats aren't as important in an airplane as in a bus," laughed Karl.
"No bumps in the air."

On either side of the cabin were two chairs, placed several feet
apart. In the middle of the floor was a small folding table, which the
boys guessed had been placed there by Karl as a convenience to members
of the expedition. A wide glass window separated the pilot's cockpit
from the passenger section, and the two were connected by a telephone
apparatus. Three large windows were in each wall, which was slightly
curving near the ceiling. At the rear was a large compartment for
food, maps, and other equipment.

"Now that you've looked it over, how would you like to go up for a
short ride?" the aviator asked, as the others examined the ship
minutely.

"Like nothing better!" came from Bob. "Can we go now?"

"Yeah. Everybody hop in. Be sure that door's tight."

Delighted at such an opportunity, the youths and Mr. Wallace took
places in the cabin, while Karl climbed into the cockpit.

A few seconds later there came the roar of the motor, and then the
passengers felt themselves moving.

The 'plane rolled over the cement runway for several hundred feet,
then gradually left the ground and began climbing steadily.

"We're in the air!" cried Joe excitedly. He and his friend had never
been in a monoplane before. "Doesn't feel unusual, does it?"

"I wouldn't know it if I didn't see the ground dropping away from us,"
Bob said. "We'll probably appreciate the absence from jolts and jars."

This easy conversation was made possible by the heavy insulation
between the pilot's and passengers' quarters. As a result, the roar of
the engine was silenced to a remarkable degree.

When just above the airdrome, they heard Karl's voice through the
telephone.

"How does it feel?" the aviator asked. "Think you'd like flying?"

"Sure," came from Joe, speaking through the transmitter. "It's a
hundred per cent better than land traveling."

The experience was not novel to Mr. Wallace, who had once crossed the
continent in a huge tri-motor monoplane. But nevertheless he appeared
to be enjoying it as much as the young men.

An altitude of perhaps a thousand feet was reached, and then the
'plane shot ahead toward the business district of Washington.

They had been in the air perhaps five minutes when Karl's voice was
again heard through the telephone.

"See anything familiar below?"

"By George!" exclaimed Bob wonderingly. "We're right above our houses.
Suppose anybody sees us?"

"Guess not," his chum said. "They're not out, anyway."

A much higher altitude was reached, and their direction of travel was
changed.

From that height, the passengers could easily make out the business
district, including the United States Capitol, the White House, and
other government buildings. In addition, they could see several score
miles in every direction.

"Isn't that Baltimore over there?" queried Joe, his keen eyes scanning
the landscape.

"It is at that," observed Mr. Wallace. "The atmosphere isn't any too
clear, though, and we can't make it out very plainly."

"We're a great distance away, too," remarked Bob. "Wonderful when you
think about it, isn't it?"

They circled around for a few minutes and then headed back to the
airport, as the aviator did not care to use too much gas.

When again on the ground, Bob and Joe were more anxious than ever to
be among those of the expedition who would travel by air. Their
eagerness was increasing with every minute.

"You've got to let us go!" said Bob to his father, when he and his
friends had returned home. "Why, just see what we'll be missing if we
don't."

"You may be missing death," Mr. Holton returned grimly. "But then," he
went on, raising his voice, "the chances are that nothing will happen.
Any more, airplane accidents are rare. I've almost decided to go
myself. It will be a chance of a lifetime."

"Then--then you mean we can go?"

"I haven't exactly said so," the naturalist answered. "There is your
mother, don't forget."

"Perhaps she won't consider it so wonderful," suggested Mr. Wallace,
who had been induced to spend the few days before leaving with the
Holtons.

Bob's mother did not at all like the idea when it was put before her
later. But she did not protest so violently when she saw that her
husband was actually bent on going. After all, his judgment had seldom
failed him, and most likely would not now. Then, too, she was somewhat
of an air enthusiast herself, having great faith in the development of
aviation. And what Mr. Holton did she usually considered fit for Bob.

Joe had more difficulty in securing the consent of his parents, for
they were doubtful as to the outcome of such a venture. Mr. Lewis,
however, was well acquainted with Karl Sutman, and knew him to be an
excellent airplane pilot, besides being a resourceful, well-thought-of
citizen. In the end, Joe's parents consented to the youth's going,
especially when they learned that Mr. Holton and Bob intended to go.
Mr. Lewis, however, had already booked passage on a steamship, and
could not cancel his arrangement, much as he would have liked to.

The two chums were delighted beyond words.

"It'll seem strange without your father with us, though," said Bob.
"We all went together on our other trips, and----"

"He'll meet us in Mollendo," Joe reminded him, and then added: "Wonder
if Mr. Wallace will go in the 'plane?"

That person desired very much to do so, but hesitated to let Mr. Lewis
make the ocean trip alone. Joe's father, though, declared he would not
be without companions, for he was acquainted with several members of
other divisions of the expedition. A Mr. Thomas L. Wells, of the
division of ethnology, was a very close friend of the naturalist.

"So, although I would like for you to come with me on the boat, I want
you to go in the airplane," Joe's father said to Mr. Wallace,
"because I know you are bent on doing so, and it is a wonderful
opportunity."

The result was that Mr. Wallace made preparations to go by air, much
to the delight of Bob and Joe. Since their first meeting with the
naturalist several months before, the youths had taken a great liking
to him.

Making ready for the airplane trip was a novel experience to Bob and
Joe. They found there was much to be purchased in the way of suits,
caps, goggles, and other provisions. Aviator's togs, the young men
knew, would not be strictly necessary, as it was a monoplane with a
closed cabin. But they thought it best to get them, since they could
also be used for general outdoor clothes.

"Here's something the express man left you, boys," Mr. Holton called,
when the chums returned from a shopping trip downtown.

Eagerly Bob and Joe opened the large box. A minute later, when they
saw its contents, they uttered exclamations of joy.

"The moving-picture camera and film, from the Neuman Motion Picture
Corporation!" cried Bob happily. "It got here just in time, didn't it?
We'll be leaving day after tomorrow."

The Neuman Motion Picture Corporation, a large firm that released
educational films, had engaged the services of Bob and Joe on their
two previous expeditions. The youths took moving pictures of the
strange lands they visited, and so pleased the film company that they
were given the opportunity of again taking moving pictures while in
the Andes Mountains. Always the boys were paid a substantial sum for
their trouble, which to them was sheer pleasure.

"Inca land you'll find to be perhaps the most interesting place you've
photographed," Mr. Holton told them. "If you do this well, the company
will almost eat you up in their praise of you."

"The Inca empire is still sort of a mystery to me," said Joe. "I've
read quite a bit about it, and Mr. Wallace and Bob and I saw that
movie in Chicago, but it's still all not quite clear. I know how the
country around there looks. It is the empire itself that I don't know
much about."

"Not being an archæologist, I don't know a great deal about it," Mr.
Holton said. "Perhaps not much, if any, more than you fellows. I do
know, though, that the Incas maintained a socialistic state, in which
everyone was forced to work on a given piece of land without deriving
any direct benefit. The grain that they raised all went to a common
storehouse, and everyone drew from it in times of stress."

"A sort of depression insurance," laughed Joe.

"Might call it that," the naturalist said with a smile. "At any rate
it seemed to prove effective."

"How about the wild animals and birds in Peru?" asked Bob. "Are there
many there?"

"Now you've mentioned a subject that I know something about," returned
Mr. Holton. "Yes, there are countless numbers of interesting wild
creatures in those mountains. Most impressive of all is perhaps the
condor, the largest bird that flies. We naturalists wish particularly
to investigate reports of a species of condor that is pure white in
color. Whether we'll find it we have yet to see. But there are other
birds and animals that we feel sure of getting, such as the puma,
armadillo, lizard, guanaco, fox, and snipe. We aren't allowed a great
deal of time in the Andes, but we feel certain that a large number of
wild creatures will fall at the report of our rifles."

The next two days were busy ones for Bob and Joe. They frequented the
business district often to get minor articles that they would need on
the trip, and by the time the great day of leaving came they had
finished all preparations.

After breakfast Mrs. Holton and Mr. Lewis drove the leavetakers to the
airport. When they arrived at that place they found that an expert
mechanic had just completed a thorough inspection of Karl Sutman's
monoplane, and had found it in perfect running order.

Their belongings were all placed in the provision compartment, and
then, with sincere farewells, the youths, Mr. Holton, and Mr. Wallace
climbed into the cabin, while Karl took his place in the cockpit.

The engine was started, and then, after the travelers had called out
one last farewell and promise to be careful, the monoplane rolled
heavily over the concrete runway and pointed its nose toward the
southern sky.

"We're off!" cried Joe excitedly. "Off for the Andes Mountains!"




CHAPTER VIII

Caught in the Storm


As the monoplane rose higher, Bob and Joe and the others waved to the
little group below until it faded from view. Then they turned to take
in the country they were passing over.

Streets, buildings, vehicles, and people were mere specks below, as
Karl sent the machine to a new high altitude. Past the city of
Washington, and then on--on above the many small cities and towns of
southern Maryland.

"Wonderful view!" breathed Joe Lewis, gazing out at the wonderful
panorama that was spread out before them.

"Bet we can see fifty miles," added Bob. "There's the Potomac River
over there, and away off in the distance seems to be the ocean. I
wonder if it is?"

Bob and Joe were strangely unaware of forward movement, though they
were going nearly twice as fast as the fastest automobile. The
comfortable enclosed cabin kept out the fierce roar of the wind, and
heavy insulation silenced the noise of the engine to a remarkable
degree. Thus they found it easy to carry on conversation.

They made the hundred-and-forty-mile trip to Norfolk in little more
than an hour. Then, after leaving this city behind, they passed over
North Carolina until finally the ocean loomed up before them.

When the last stretch of land had been left behind, Bob and Joe were
thoughtfully silent. What if anything should happen while they were
out here above the boundless water, with no place near on which to
land? It was not pleasant to think of plunging hundreds of feet into
the ocean, even though the water might be calm.

As they flew farther, Joe was surprised that they had not seen ships
below them.

"This isn't a route of travel," explained Mr. Holton. "We probably
won't see any large liners till we get farther south."

Later they were able to make out several tramp steamers, which, when
viewed at that altitude, appeared to be at a standstill. Just where
the vessels were heading the air travelers could only guess.

Suddenly, unexpectedly, the youths and the naturalists found
themselves in a heavy cloud, which hid the ocean from view. It was so
dark that Mr. Wallace almost mechanically switched on a light.

"Wonder if this means danger?" mused Joe, gazing intently out of the
window at the haze.

"I was wondering the same thing," came from Mr. Holton. "If it does,
we ought to hear from Karl before long."

But before long they passed out of the cloud and once more could see
the ocean. But now the sun was nowhere in sight.

"We may have some rain," said Karl through the telephone. "Be sure all
the windows are closed tightly."

Bob wondered if rain would be a hindrance to flying, although he
hesitated to put the question before Karl. If the truth were known, he
was not a little worried.

As they flew farther the sky became more overshadowed. Dark,
threatening clouds hovered near, as if to warn the air travelers to
seek a place of refuge. It was not a pleasant sight to the four
passengers.

All at once they had a sudden sensation of falling, which almost took
their breath away. It lasted but a brief moment, however, much to the
relief of all.

"What caused that?" asked Joe, who had turned pale.

His question was answered a little later by Karl.

"Feel that drop?" the aviator asked. "I did that to see if we can't
get below the storm area."

"How far did we fall?" inquired Mr. Wallace interestedly.

"Only a few hundred feet. And I steered over to the east, too. We seem
to be out of the storm area."

Now, as they flew on, the travelers could easily glimpse the dark mass
of clouds that they would have been forced to pass through had they
remained strictly on their course.

An hour or so before noon, the explorers caught sight of a little
group of islands, and in the distance they could make out one that was
much larger.

"We're nearing the West Indies," observed Mr. Wallace jubilantly.
"That large island away over there is probably Abaco."

As they neared the land, Karl dropped to perhaps a thousand feet. From
this altitude they could command a good view of the country below
them. It was for the most part wild and uninhabited. There was a great
deal of fog hovering about, or they could have seen many more islands.

They were nearing the tropics, as evidenced by the mercury rising in
the thermometer. As they were traveling evenly, it was safe to open
the windows. The resulting gush of wind was at once greatly
appreciated.

"We'll have about three hundred and seventy-five miles of traveling
before we reach Cuba," announced Karl, as they passed over a large
cluster of islands. "Maybe we'd better land there, at least for a few
minutes. It'll give the 'plane a chance to cool off, and then, too, we
can look it over."

It was three hours later that Bob caught sight of what appeared to be
a long black line stretching out of sight to their left. That line
gradually took shape and color, and the explorers found themselves
nearing Cuba.

On the side nearest them was a large mountain, with a cone-like top
that gave it the appearance of a volcano.

Within sight of this peak, Karl picked out a level stretch of ground
and sent the monoplane downward. He found it necessary to make a
spiral landing, as there was danger of otherwise striking a line of
low, sharp peaks.

Bob and Joe watched closely as the ground came up to meet them. Then
they felt the wheels bump, and they knew they were safe.

"All out!" called Karl, appearing at the cabin door. "That is, if you
want to rest your legs."

The others needed no urging. They climbed stiffly out of the 'plane
and stretched freely. While they had not been cramped, they had
nevertheless not been allowed the freedom of violent exercise.

"So this is Cuba," observed Joe, yawning and looking at the green
jungle, which seemed everywhere about them.

"Not much to be seen in this part of the island," Mr. Wallace told
them. "We're at the extreme eastern end."

They looked around a bit, though, to satisfy their curiosity.

When they finally returned to the 'plane, after taking a tramp toward
the high peak, the explorers were ready to devour anything in the way
of food.

Sandwiches and iced tea, the latter having been kept cold in a thermos
jug, served as a meal, and proved to be very satisfying to the hungry
explorers.

Then, after taking a short rest in the shade of the monoplane, they
prepared to resume the journey.

"Now comes the worst part," said Karl, with a frown. "We'll have to
fly for over five hundred miles without seeing a trace of an island.
The Caribbean Sea may prove treacherous for tropical storms, too."

Luck was with them the first half of their trip. The sky remained
clear and light, not giving the slightest indication of a change of
weather.

Then suddenly, when the travelers' hopes were high, they noticed that
the sky was becoming dark and threatening. A fierce wind was blowing
with a dangerous velocity, which threatened to send the monoplane off
its course.

Karl guided the machine off to the west, in the hope of passing beyond
the storm area. He speeded up to over a hundred and fifty miles an
hour, for he knew that whatever he did must be done quickly.

But try as he did, he could not escape the heavy clouds and terrible
wind.

His hope almost gone, he sent the ship to a much higher altitude,
thinking it might be possible to get above the clouds.

But it was too late. With a rush and a roar, the tropical hurricane
was upon them.




CHAPTER IX

A Fearful Discovery


Never in their lives had the explorers witnessed anything like the
terrible onslaught that followed. The violent, ruthless wind dashed
the monoplane about dangerously, threatening at every moment to tear
it to pieces. It was but a frail, man-made machine when caught in
those forces of nature.

Karl's ability as a pilot promised to be tested to the utmost. If he
could keep the ship straight it would be nothing short of miraculous.
The less skillful aviator would send his craft dashing down to the
foamy water below. But Karl was by no means a novice. He had had wide
experience in piloting passenger monoplanes on schedule across the
United States.

"Sit tight!" he called through the telephone, suspecting that his
friends were frightened. "We'll get out some way--I hope."

Every gust of wind tossed the 'plane about hazardously. It seemed
that a plunge would be inevitable.

In the cockpit Karl Sutman was determined to bring his friends and
himself safely through the danger. With nerves of steel, he hung on
desperately to the stick and the rudder bar, keeping his keen eyes
glued to the horizon.

It was indeed a race between life and death, as the staunch 'plane was
swung about at the mercy of the storm. Many times before had the
machine proved itself capable of withstanding the assault of the
elements, but this was the supreme test. If it could weather this, it
would indeed be a strong machine.

Inside the cabin, the youths and the naturalists were pale with an
awful fear that this would be the end. They could not conceive of
passing safely through such a hurricane as this. They were only too
aware that many an aviator had gone to his doom in a tropical storm.

Now, to add to the terrible scene, a heavy rain began to fall, coming
in great gusts with the wind. It pattered ominously on the wings,
bearing the monoplane down with the added weight.

"Oh!" groaned Joe, almost giving up in despair. "I suppose the worst
is yet to come."

"Cheer up," said Mr. Holton, who was inclined to be hopeful, as he
noticed that the wind was blowing more evenly. "It can't last so very
much longer."

Despite this expression of optimism, the hurricane continued at full
force, although a bit smoother than at first. Now the wind, instead of
coming in great gusts, blew steadily.

This made it slightly easier to handle the 'plane and took some of the
severe strain from Karl. But he still was forced to use all his energy
in keeping the craft at as even keel as possible.

All knew that a tropical storm was usually over a wider area than one
in the temperate zone. It was this that had made it impossible for
Karl to steer the 'plane to safety before the gale struck.

Only gradually did the monoplane pass through the clouds, which
extended many miles in every direction.

Finally, when a clear sky again became visible, the explorers uttered
cries of relief. They had at last escaped what seemed like certain
disaster.

Bob moved over to the transmitter.

"You were wonderful, Karl, old boy!" he praised. "If most anyone else
had been in your seat, we wouldn't be in the air now."

"Oh, there are plenty others that could have done it," the aviator
returned, his voice sounding a bit nervous. "I just saw that I had to
get out some way and did everything I could."

The storm had served in no small measure to heighten the explorers'
admiration for their pilot. If the latter could safely guide them
through such a display of the elements, he could be depended upon for
almost any crisis.

The brilliant sun was now rapidly showing itself in full view, casting
a sparkling reflection on the ocean. All evidences of the storm were
covered up, even the heavy foam caps having disappeared. It was as
though nature were repenting of her arduous activities.

As they flew on, the explorers had a strong hope that the weather
would remain calm during the remainder of their journey. They were
nearing land now, and they wished to finish the trip in a cloudless
sky.

At last, when they were becoming weary from seeing nothing but
boundless water, they suddenly caught sight of a dim shape that
covered the whole of the horizon. That shape became larger and more
plain, until it took on the form of land.

"Hurrah!" cried Bob joyfully. "South America at last!"

"I believe you're right," came from his father. "It----"

"Announcing our arrival at the great continent of South America!"
Karl's voice, coming loudly through the telephone, broke off with a
laugh.

As they came nearer, the aviator guided the machine to a lower
altitude, although still high enough to see many miles in every
direction.

But it was a long while before they could make out plainly the details
of the coast. Fog made it necessary to fly very near in order to see
anything distinctly.

"I believe I can make out the Andes," said Joe, gazing out at the
distant horizon.

"Don't be sure," laughed Mr. Wallace. "Those mountains are a long way
off."

Before long they had passed the coast and headed over the land, almost
directly above the Magdalena River, whose course they could easily
make out.

For the most part, the country they were flying over was rugged and
uncultivated, but there were occasional towns and villages that dotted
the valleys and clearings.

"Bogotá is the first large city we'll see," announced Karl. "We ought
to get there by tomorrow noon."

"Where will we spend tonight?" asked Joe, as he noticed that darkness
was not far off.

"Suppose we land before long and put up our tent," suggested Mr.
Holton, stepping up to the telephone transmitter.

"I was just getting ready to do that," Karl answered him, and then
added: "Here's a good spot now."

There was a wide, level field directly below them. Karl sent the
monoplane off to the west and then headed it back and downward.

A perfect three-point landing was made in the tall grass, the ship
coming to a stop at the very edge of a frowning jungle.

Once more the explorers got out and stretched their legs.

Bob and Joe had just started over to the jungle when they heard
something that made them turn about quickly.

"There's a leak in the gas tank," Karl said ominously, "and the gas is
almost gone. We landed just in time."




CHAPTER X

Train Robbers!


At Karl's dread discovery the others uttered exclamations of alarm and
astonishment.

"What could have caused it?" asked Bob grimly.

The aviator shook his head.

"Can't say," he returned. "Maybe something pierced it while we were in
Cuba. Could have made a small leak that let out a little at a time. Or
the storm could have done it."

"Good thing we were able to make it across the Caribbean," remarked
Mr. Holton. "If it had been much larger, perhaps we wouldn't be here
now to find it out."

The short-lived tropical twilight was upon them, with a promise of
darkness being only a few seconds off.

"Suppose we put the tent up while we can see to do it," suggested Bob.
"Then we can attend to the leak in the morning. There's some solder in
the provision compartment, and we can put some of it on now to keep
the remainder of the gas from running out."

The others thought this good advice. While the youths and the
naturalists made camp, Karl Sutman applied a heavy coat of liquid
solder over the cut in the gasoline tank.

"I guess we're in a mess," the aviator said disgustedly. "We've used
up all the gasoline in the spare tank, and now we haven't enough to
take us twenty-five miles. We could have flown to Bogotá easily if it
hadn't been for that leak."

"Bet there isn't a gasoline station within fifty miles of here,"
groaned Joe, glancing at the rugged country that was on all sides of
them.

Darkness overtook the explorers before they had completed making camp.
They were forced to turn on the lights of the monoplane until they
could gather sufficient twigs for a fire.

When finally a roaring blaze illuminated the sky, they turned to
complete making the camp.

As a precaution, this was made on a spot several hundred feet from the
monoplane. This would do away with the danger of an explosion, for the
intense heat from the fire might easily have ignited the remaining gas
in the tank.

"Now to get a meal," said Bob, edging closer to the blaze to escape
the chill of the tropical night.

A delicious spread of food was prepared, all eating heartily. The
eventful day had stimulated their appetites highly.

"I suppose there's no use worrying," grunted Karl, stretching out
before the fire. "We'll find a way out somehow. If we can't do
anything else, we can all hike to a town and carry back enough gas to
carry us a short distance. Then we can hike to another town, and do
the same thing over again."

"Do these towns around here have gas, though?" came from Joe. Despite
Karl's expression of hope, he feared the worst.

"That we don't know," Mr. Wallace said. "It may be there hasn't been
an internal-combustion engine in this region for years, if at all."

A rapidly growing exhaustion made the explorers for the time being
forget their cares and curl up in the tent, after having heaped the
fire high with fresh fuel. They had not thought it necessary to stand
guard, as there was probably nothing in this region that would bother
them.

The next morning Karl got out a map of South America and spread it out
on the tail of the machine.

"Here we are about twenty miles inland," he said. "The nearest town
appears to be about fifteen miles from here. Luckily it's south, and
we won't have to go much off our course."

"Think we can get gasoline there?" queried Joe.

"Probably not," Karl answered. "But if we have to we can take a train
to Cartagena--that's a city not far from here on the coast. Of course
they have gas there."

They climbed into the monoplane, which, with a roar, rolled over the
high grass and headed south. Karl kept the machine going at as slow a
speed as possible, for he desired to use every ounce of fuel to
advantage. But even then they made the short trip to the little town
in but a few minutes.

"Here we are, right near the town." Karl climbed out of the cockpit
after having made a perfect landing.

Scarcely had the explorers stepped to the ground when they caught
sight of a score or more natives running toward them. It was a motley
crowd that surrounded the Americans a few seconds later.

Surprise, bewilderment, amazement were displayed on the faces of the
Colombians. The monoplane they viewed with a certain awe that was
almost childish in its sincerity.

As soon as the jabbering had abated somewhat, Mr. Holton addressed
them in Spanish, asking if it might be possible to procure gasoline
for the airplane.

The faces of some were expressionless, but a few shook their heads.

"We do not use gasoline here," one man said in the native tongue.
"There are no great birds like this"--pointing to the monoplane--"in
our land. And we have no carriages that are not drawn by animals."

Mr. Holton then asked if it might be possible to get gasoline in
Cartagena, the city on the coast.

Strange to say, the people did not know. Evidently they had never been
to that place, although it was less than fifty miles distant.

"Well, then," began Karl, "I suppose one of us will have to take a
train to Cartagena. Whoever goes can take a gasoline can with him and
get it filled. Then he can return on the next train." The Americans
could not help laughing at this, however necessary it might have been.
The idea of boarding a train for a fifty-mile journey merely to get a
can filled with gas seemed provoking.

"What a predicament!" roared Bob, catching hold of the monoplane in
order to hold his balance.

"I suppose we ought to take this more seriously," said Karl, who was
also laughing. "But somehow it all seems humorous to me."

At sight of the Americans laughing, the crowd of natives looked about
sullenly. No doubt they thought the newcomers were making fun of them.
Finally one man stepped up to Bob, and, with a sneer, uttered
something in the native language.

The youth could only catch a word or two, but it was enough to make
him glare at the man in anger.

"Be careful, Bob," warned his father. "There are too many of them for
us to get into a scrap."

"Aw, I could lick them all with one hand!" snarled the youth, his eyes
resting fearlessly on first one and then another of the men.

He was able to control his temper, however, and as the Colombians made
no further move, he turned to Karl Sutman.

"Why can't I make that train trip?" he asked. "I'll pay my own fare.
Really I'll enjoy it."

"All right," came from Mr. Wallace. "And I'll go with you. It will
take two to carry the gas can when it's full."

"Be careful," warned Mr. Holton. "We won't be surprised if you're gone
a day or two."

At the railroad station, which was little more than a mud hut, they
found that a train would arrive in less than three hours. They thought
it best to remain near the depot, for the schedule might not be
accurate.

The train finally came, but, much to their disgust, the two gas
seekers were informed by the conductor that they would arrive in
Cartagena no sooner than four hours later.

At last they started moving and slowly left the station behind. The
little crowd that had assembled to see the train off waved a farewell
as it disappeared around a curve.

Bob and the naturalist gazed intently out of the window at the barren
country they were passing through. Only at intervals could they make
out an adobe house.

They had gone perhaps an hour when they were startled by a sudden
commotion at the head of the train. Bob was looking out of the window
trying to make out what was going on when he suddenly felt the train
come to an abrupt stop.

Wondering what was meant, he and Mr. Wallace had started toward the
front of the coach when they were interrupted by a cry that echoed
through the train.

"We're being robbed!" exclaimed Mr. Wallace, hurrying back to the
seat. "There's a gang holding up the train!"




CHAPTER XI

Chubby the Eater


"Robbed?" cried Bob, almost unbelievingly.

Before he could say anything further, a tall, dark man appeared at the
front of the coach. Roughly he shouted something in the native tongue,
at the same time flashing a shining pistol in full view of all.

"Quick!" exclaimed Mr. Wallace, taking advantage of an opportunity.
"Hide our money--under the seat there next to you."

The naturalist handed his pocketbook to Bob, who had taken his own
purse from his pocket. The two he placed in a little crack between the
seat and the side of the coach.

He was not a moment too soon. Scarcely had the youth resumed his
natural position when the robber appeared before him and demanded
money.

"Our pockets are empty," Mr. Wallace told the man. "You can't get
anything from a poor man."

The Colombian soon found that the naturalist spoke the truth. But
even then he was a bit suspicious. Americans or Europeans--he knew not
which they were--usually were rich, carrying with them much money. And
that these two had boarded the train with empty pockets was indeed
surprising.

Search as he did, however, he could find no trace of any money. But he
was somewhat satisfied when he took possession of Mr. Wallace's
handsome watch.

Luckily Bob had left his timepiece in the cabin of the monoplane,
having forgotten it in the excitement of the day. Strange to say, this
was the first day in the week that the youth had not worn it.

"Well," said Mr. Wallace, after the man had gone, "I lost the
equivalent of fifty dollars. Not a great deal. But too much to have
taken from me."

"Good thing you thought to mention hiding our pocketbooks," Bob told
him. "If you hadn't, we'd have been in a fine mess. Away out here in a
strange country with no money."

"And of course the railroad wouldn't have made it good," the
naturalist said disgustedly. "If I ever have another watch I suppose
I'll have to pay for it."

Ten minutes later the train was again chugging across the barren
plateau. The robber gang had vanished before a cloud of heavy dust,
perhaps not any too well satisfied with its exploit.

"I didn't know this was dangerous territory," remarked Bob Holton a
little later. "Seemed like everyone was too lazy to do anything but
loaf."

"I guess we'll find gangs anywhere we go," Mr. Wallace told him. "At
least that's my opinion, after quite a bit of traveling."

Bob recalled the bands of criminals he had met with at home and on the
Sahara Desert, and concluded that his friend was right. No matter how
much good there is in the world, there is always a certain amount of
bad.

Two hours later the Americans were surprised to see that they were
coming into a town. At the railroad station where they had boarded the
train, they had not been told that another town was between them and
the coast.

"This is Mahatos," announced the naturalist, pronouncing the name as
best he could.

"Guess everyone here wants strangers to be sure and know what town
they're in," laughed Bob. "At any rate, that sign is plenty large.
Almost hides the station."

This town was much the same as the one at which they had boarded the
train. They were glad when finally it was left behind.

"Wonder if we'll make any more stops?" mused Bob with a smile.

"Don't be surprised if we do," Mr. Wallace replied. "For all I know
there may be a dozen villages between us and the coast."

During the next two hours the train crawled along without coming to a
settlement. Then finally it passed a row of little black houses and
pulled into Cartagena, the coast city.

"All out," said Mr. Wallace, picking up the large gasoline can. "We've
reached our destination at last."

As the Americans looked about the well-built station, they found that
this was a city of considerable importance. Crowds of people,
clusters of business houses, and--what was more interesting to
them--automobiles dotted the streets.

"Where there's a motorcar there's gasoline!" cried Bob joyfully. "Now
who says we won't put fuel in the airplane tank!"

They found a filling station--or at least a place where gasoline was
sold--not far away and lost no time in having the can filled to
capacity. Then they turned back to the railroad station.

"Our business in this city is completed in five minutes, after having
made a four-hour trip here!" Bob could not help bursting out in
laughter, and Mr. Wallace joined him.

They entered the railroad station and inquired when they might board a
train back to Calamar.

Much to their displeasure, they found that it would not be possible
to do so until the next morning. The agent explained that it was
necessary to repair a portion of the track, and that until this was
completed, a run could not be made.

"Just as I expected!" groaned Bob, sitting down on the seat
hopelessly. "To save your neck you can't make time in South America."

"What will we do to while the time away?" asked the naturalist.

"Look around, I suppose. Nothing else to do."

The Americans found Cartagena very interesting. Its several industries
were throbbing with life; its people were possessed of a certain
amount of energy and ambition that was entirely absent farther inland.

The travelers were loitering along at the port, watching the steamers
arrive and depart, when Bob suddenly caught sight of something that
caused him to nudge his friend.

"Look at that fellow over there," the youth pointed out. "Isn't he an
American?"

Almost at once Mr. Wallace made a reply. "He is as sure as I'm born.
Or else"--the naturalist hesitated--"he's English."

The object of their remarks was a short, fat young man of perhaps
twenty, with twinkling eyes and a pug nose. He was dressed in khaki
outdoor clothes that stretched tightly over his protruding stomach.

Before Bob and the naturalist could make a further move, the strange
young man walked over to them, his small, deeply set eyes flashing
with merriment.

"Ain't you from the good old U. S. A., or ain't you?" he demanded,
extending a short, fat hand.

"From nowhere else!" Bob was overjoyed. "And I take it that you are?"

"Right as four chipmunks!" the little fellow said quickly. "You're
lookin' at Chubby Stevens, from Houston. And now that I've got that
off my chest, I ain't expectin' you to hold your names a secret."

Bob laughed.

"This is Mr. Wallace, and my name's Holton--Bob Holton. I'm from
Washington and my friend's from Chicago."

"A good bit of the _Estados Unidos_ is represented here, I see,"
Chubby said with a laugh. "The East, Middle West, and Southwest. I
suppose you're just lookin' around?"

"For the present, yes," Mr. Wallace returned, and then related the
events that led to their being in Cartagena.

The fat youth listened intently.

"You may be wantin' more of South America, but I don't," he said when
the naturalist had finished. "I've been here a year and have got all I
want of it. I'm longin' to see the old Gulf Building, back in Houston.
Dad's office is there. He's a lawyer."

"And you--what are you doing here, just seeing the country?" inquired
Bob.

"I'm seein' too much of it to suit me," Chubby answered. "Came here to
look around and to get rid of some fat. But doggone it, I'm fatter now
than I ever was. Guess I'll have to cut out adventurin' and take back
my old job in the office, if I want to get skinnier."

A burst of laughter followed.

"You're hopeless, all right," chuckled Bob. "I never saw a case like
yours before. Why, I weighed a hundred and eighty before I left the
States, and I'll bet I don't weigh much more than a hundred and
seventy now. If exploring would do that to me, why won't it do it to
you?"

"That's what I've been tryin' to figure out for the last year," Chubby
returned. "Funny, but I used those same figures, but I just switched
them around. Went from a hundred and seventy to a hundred and eighty.
That's away too much weight for a bozo my size to carry around."

"Why don't you try swimming back to America?" laughed Bob. "That
might do the trick."

"I've been thinkin' about that, too, only I'm afraid I couldn't take
along enough to eat."

"Oh!" Bob groaned hopelessly, and then, as he found that Chubby had
just arrived in Cartagena, suggested that they take a walk about the
city.

But as it was almost noon, Chubby suggested that they get a "bite" to
eat. Just enough, he said, to prevent them from falling from hunger.

Mr. Wallace snorted.

"I suppose it's impossible to do it," the naturalist said earnestly,
"but I'd like to take you along on our expedition into the Andes. If
you'll go, I'll guarantee that you'll get rid of twenty pounds."

"Huh? Are you tryin' to kid me?" Chubby looked up suddenly.

"Not a bit of it," Mr. Wallace answered, trying hard to suppress a
smile. "It works every time. You see, we have to get by on limited
rations and----"

"Fine! I'll go---- What was that you said? Limited rations? That means
less food, doesn't it?"

Mr. Wallace nodded.

"Then I'm afraid," began Chubby, shaking his head slowly, "that I
couldn't think of considering your proposition, however wonderful it
might be. I'm----"

"It's no use," laughed Bob. "A heavy eater doesn't make an explorer."

Bob and the naturalist were finally persuaded to follow the fat
youth's suggestion and get a "bite" to eat. Then they continued their
sightseeing.

Thus the remainder of the day passed, and they began to look about for
a place to spend the night. Chubby resolved to remain with his newly
found friends as long as the latter stayed in Cartagena. Then, he told
them, he would take a boat to the United States.

The three Americans engaged a small room in a boarding house that was
owned by a Canadian. Although it was not the utmost in comfort, they
were glad to throw themselves on the hard bed to retire.

They passed a restful night, however, awaking late the next morning.

"What shall we do until train time?" asked Bob, preparing to leave the
room.

"Look around some more, I suppose," Chubby said. "In this country you
can always find something you haven't seen before. There's a lot
that's funny, too. I've been laughing a year at the natives."

"Maybe they've been laughing at you," Bob thought to himself, but said
nothing. The fat little fellow would indeed provoke a smile from
many.

Until ten the three walked around the city, noticing everything that
was peculiar to this strange land. When finally they came back to the
railroad station, they were not a little fatigued. Especially tired
was Chubby.

"Well," Bob began, "we'll leave in fifteen minutes, if we follow the
set schedule. I suppose," he said to the fat youth, "you've definitely
made up your mind to go back home?"

"Yeah."

"Then you won't think of going with us to the Andes? We could use you,
all right."

"Sorry, but it's North America for me." Chubby spoke decisively. "This
continent here ain't fit for a gazook like me. I want to get back."

He exchanged addresses with Bob and Mr. Wallace, pocketing his
notebook just as the train steamed up to the station.

"Good-bye and good luck!" called Bob, as he stepped up into the coach.
"Write us sometime."

"Hope you lose some fat," laughed Mr. Wallace, as they started moving.
"And you'd better not try to swim to the U. S."

The train moved slowly away, leaving Chubby to stand on the platform,
still waving.

"Good fellow, all right," smiled Bob, settling himself down in the
seat. "All he needs is a little well-directed exercise."

"I'm afraid he won't get it," said the naturalist. "He'll probably be
fat as long as he lives."

The journey back to Calamar was uneventful. Bob and Mr. Wallace looked
out rather fearfully as they passed the spot where they had previously
been robbed. But no gang appeared this time to stay them.

Finally they reached their destination and left the train. They were
greatly surprised to see that no one was there to meet them.

"That's funny!" mused Bob, as he and the naturalist lugged the heavy
gasoline can in the direction of the airplane. "I thought sure Dad or
Joe would be here."

When at last they came to the airplane, Bob gave a cry of surprise.

Seated on the ground were Joe, Karl Sutman, and Mr. Holton, their
faces bleeding from numerous scratches, their clothes torn and
wrinkled.




CHAPTER XII

The Pangs of _Soroche_


"For the love of Mike!" cried Bob Holton. "Whatever happened?"

"Plenty!" came from Joe quietly. "We had a fight."

"A fight?" Mr. Wallace was perplexed.

"Yes, and a big one at that," said Karl grimly. "But we licked them."

"Licked whom?" demanded Bob, becoming impatient. "Come on. Tell us
about it."

Mr. Holton got to his feet.

"Look over there," he directed, pointing to a spot near the tail of
the monoplane.

Bob and Mr. Wallace looked.

Lying prone on the ground was a man, a native Colombian, evidently
still dazed from a blow. He made not the slightest move, although it
was apparent that he was not hurt seriously.

"Karl knocked that fellow out," explained Bob's father. "In addition
to being a fine aviator, that fellow's a fighter."

Bob glanced at Karl. From the start the youth had believed the aviator
could give a good account of himself if called upon.

"But that's not telling us anything," said Mr. Wallace. "What caused
the fight? How did it all come about?"

"This way," began Mr. Holton. "Joe and Karl and I were sitting in the
cabin of the 'plane discussing the expedition when we were suddenly
interrupted by a gang of at least five rough men, who rushed at the
'plane angrily. We didn't know what their object in attacking us was,
and never did find out. Perhaps they wanted to steal what we have, or
they might have been in that crowd yesterday when we laughed and they
thought we were making fun of them. At any rate they came at us
furiously, and one man broke out the glass in a window. We got out of
the airplane as soon as we could to defend ourselves. We couldn't get
to our guns because they're in a nailed box. But we used our fists to
good advantage and finally were able to beat them off. All got away
but that fellow over there."

"Well, of all things!" exclaimed Mr. Wallace. "Seems like we're having
trouble and then more trouble. Bob and I had an experience on the
train that wasn't very pleasing," he said, and then told of the
robbery in which he had lost a valuable watch.

"We'll soon be out of this country, I hope," sighed Joe. "Though I
suppose it isn't the country so much as it is our stroke of bad luck."

"No," agreed Bob. "Anyone----"

He stopped quickly, as he observed that the Colombian who had been
knocked out was regaining consciousness. At first the man merely
stirred about, as if totally unaware of what had happened. Then he
glanced up and got to his feet.

Pausing but a moment to glare at the Americans, the man dashed away in
the direction of the town, drawing his teeth back in a wicked snarl as
he looked back at them one last time.

"I think we'd better get away from here as quickly as we can," said
Mr. Holton. "For all we know there may be another gang getting ready
to attack us. The whole town might even come out."

His remark served to set Karl Sutman to action.

"Let's get the gas in the tank," he suggested, walking over to the can
that Bob and Mr. Wallace had brought filled from the city on the
coast.

Together, Joe and the aviator lifted the heavy can up and poured out
its contents. Then, after making the cap secure, Karl climbed in the
cockpit and switched on the engine.

"This will take us from fifty to seventy miles--maybe farther,
depending on how fast we fly," he told the others, as they entered the
cabin and snapped the door shut.

As they left the ground, Joe noticed that they were heading west. He
wondered what was the meaning of this, since Bogotá, which was south,
was their goal.

"I'm going to find out," he thought, and, stepping over to the
transmitter, he put the question to Karl.

"I decided all at once to go over to that coast city--Cartagena," the
aviator answered. "There we can fill both our tanks to capacity and
won't have to worry any more. Otherwise, if we merely used the gas
that Bob and Mr. Wallace brought, we might find it necessary to hunt
up another town that has gasoline."

"You think of everything," praised Bob's father, moving up to the
transmitter.

"I've decided to make another change, too," Karl said with a laugh. "I
think it might be best to miss Bogotá by a hundred miles and head at
once for Lima, the capital of Peru. We can stop at Quito, the capital
of Ecuador, for more gas, and then continue on to Lima. Here we'll
again land to fill our tanks. After that we'll go on to--well, perhaps
to Cuzco, if we want to look around a little before Mr. Lewis gets
here by steamship. How does it sound?"

"O. K.," said Bob quickly, and then, with a sudden thought, added:
"How about the tank that leaks? Can we have it repaired in Cartagena?"

"Yes. That is, I'd think so. Why didn't you and Mr. Wallace find out
while you were there?"

"Upon my word, I never thought of it," confessed the naturalist
sheepishly. "And I'm sure Bob didn't. But we could easily have
inquired. After seeing the city, I'm inclined to think the tank can be
repaired there."

They found a little later that Mr. Wallace was right. At the first
garage they entered, they were informed that the tank could be
repaired.

It was necessary, however, for the garage man to take his welding
outfit over to the monoplane, which was in a field quite a distance
away. For this he explained he would be compelled to make an
additional charge, but the others, knowing there was no other way out,
did not object.

When the tank was mended and had cooled an hour or so, it was filled
to capacity with gasoline. The spare was also filled, and then the
explorers were ready to resume their journey.

A little crowd of people had assembled to see the monoplane off. They
waved a friendly farewell as it soared high into the sky.

"Now I wonder if we'll have any more trouble," mused Bob. "Or will we
have good luck and get to the Andes without much delay?"

Across jungle, plains, and hills they flew for well over an hour. Then
they caught sight of something in the distance that thrilled them with
delight.

"The Andes!" cried Joe joyfully. "At last we've seen the Andes
Mountains!"

"I believe you're right," affirmed Mr. Wallace, straining his eyes to
make out more clearly the series of distant bumps that were mountains.

As the explorers flew nearer, they could easily observe the high peaks
and narrow valleys. At one time they flew directly over a short range
of exceedingly lofty mountains.

The monoplane passed farther, and the towering slopes of the Andes
became more prominent. They looked dark and forbidding, yet beautiful
and romantic.

"It's going to be dark before long," said Karl, breaking the
fascinating silence. "And as it isn't wise to keep going over unknown
territory, I'm going to land--if I can find a place."

Picking out a level spot was very difficult, but finally Karl caught
sight of a flat plateau stretching several hundred yards ahead. He
brought the machine down as best he could, taking into consideration
the difficulty of landing at high altitudes.

They did not pitch the tent that night, but curled up inside the
cabin, too tired to use much more energy. By doing this they could
lock the doors and spend the night in comparative safety. Otherwise,
it would have been necessary to set a guard.

A heavy slumber overtook them and held them firmly until late next
morning.

"Now to head for Ecuador," said Joe, becoming impatient. "How long
will it take us--to get to Quito, I mean?" he asked Karl.

"Let's see. We've been about an hour out of Cartagena." Karl pondered
for a minute. "There'll be about six more hours of air traveling
before we get there. That is, if nothing happens."

But nothing hindered their flight, and after a thrilling ride over
fascinating country the explorers came to Quito, at the very rim of
the lofty peaks. Karl finally was able to bring the airplane safely
down at the edge of the city. He switched off the engine, and, with
the others, turned to glimpse the surrounding mountains.

On all sides were the magnificent heights of the mighty Andes,
reaching thousands of feet above the city. Quito itself was built in a
wide valley, nearly eleven thousand feet above sea level.

All during the last hour, as they had soared steadily upward, Joe had
had a strange feeling of nausea, which grew still worse after they had
landed at Quito. Now, when they were about to make their way into the
city, Joe slumped down on the ground beside the monoplane.

"I'm sick!" he moaned helplessly. "Guess I can't go with you now."




CHAPTER XIII

A Happy Reunion


"Sick?" cried Bob anxiously. "What seems to be the trouble?" He and
Mr. Holton had moved over to Joe.

"Got a terrible headache. Feel bad all over. My--my stomach doesn't
seem right."

Almost at once the two naturalists grasped the meaning of Joe's
misfortune.

"There's no doubt about it," began Mr. Wallace, who was himself
becoming pale. "You have mountain sickness, or _soroche_, as it's
called. I think I have a touch of it myself."

"What causes it?" queried Bob.

"The high altitude," Mr. Holton answered. "You see, when one makes a
sudden change to nearly eleven thousand feet, it is a great strain on
him. Usually, though, it doesn't show up until reaching a much higher
altitude than this. I'm surprised that Joe has it so soon."

Joe did not become worse, but grew no better. One thing was apparent:
until he would show improvement, he could not continue the journey.

Mr. Holton and Bob helped him into the cabin of the airplane, where an
improvised bed was made.

"If it's all right, I think I'll stay with him," announced Mr.
Wallace. "I'm not feeling any too well myself, and then, too, Joe
ought to have someone here with him."

"All right," said Karl. "Meanwhile the rest of us will go on into the
city and have some gasoline sent out to the 'plane."

In Quito the others found a filling station, the operator of which
agreed to send out a truck to the monoplane to fill the tanks.

Back at the field they found that Joe had greatly improved and was
anxious to fly on to Lima. It was evident that he had had only a
slight attack.

In a short time the gasoline truck arrived, the tanks were
replenished, and the explorers again climbed into the monoplane.

The journey to Lima promised to be more dangerous, as there were
hazardous stretches of country to be left behind. But all knew that
Karl was a skillful pilot. If he had not been he could not have
brought them safely out of the terrible storm that they had
encountered over the Caribbean.

Mountains, valleys, towns, then more mountains were spread before them
as they flew on their way to the "City of the Kings." The rugged Andes
were more impressive than Bob and Joe had imagined.

At last they caught sight of Lima in the distance and before long were
hovering over it.

Karl singled out Faucett's Field and brought the monoplane down at
high speed in order to avert a catastrophe. Well he knew that landing
at such an altitude would present a difficulty, even at best.

"Can hardly feel the wheels touch the ground," remarked Bob. "Wonder
how Karl knows he's made a landing?"

They were rolling swiftly over the smooth ground when suddenly Mr.
Holton cried out in fright and pointed ahead at another airplane,
which was landing directly in their path.

"Look out!" he warned Karl, speaking hoarsely through the transmitter.

Karl Sutman had already seen the danger and was cutting the monoplane
to one side as best he could.

He was too late, however. The other airplane came on at sickening
speed, heading directly at the explorers. The wings of the two crafts
touched, and the monoplane sent the other machine, which was much
lighter, spinning around dangerously.

Its lower wing scraped the ground, and a support was broken. A moment
later it came to a stop, leaning on its side.

Meanwhile, Karl's monoplane had continued farther, gradually losing
speed until it came to a standstill several hundred feet away from the
other airplane.

"A narrow escape!" breathed Joe, as he opened the door of the cabin
and stepped out. "A little more and we would have been goners."

"That crazy guy ought to have his face smashed!" snarled Karl,
directing his glance at the distant airplane. "He broke one of the
prime rules of flying: Never land when there is another 'plane on the
field."

"Here he comes now," observed Bob. "Wonder what's on his mind?"

They soon found out. The other aviator was a native Peruvian and could
not speak English, but he addressed them angrily in the native
language.

Karl stepped boldly up to the man. His fist shot out and caught the
native squarely between the eyes.

The man reeled and then lost his balance, falling heavily to the
ground.

At that moment two men from the airdrome came running out and demanded
an explanation of what had happened.

Briefly Mr. Holton told them, stressing the fact that the aviator had
not waited to land.

"He ought to have his pilot's license taken away from him," growled
Karl Sutman, when the naturalist had concluded.

The men from the airdrome were greatly angered at the strange aviator
for not being cautious in landing. They addressed him in no gentle
terms as he lay on the ground.

Karl's monoplane had been only slightly injured in the accident, but
it was enough to require an hour of patient labor to make the repair.

The possibility of the other aviator doing damage to Karl's machine
prompted the tall young man to ask that it be kept under watch near
the airdrome.

"Now suppose we walk on into Lima," suggested Mr. Holton, after the
'plane had been rolled over to a safe place.

At the edge of the field was a wide street that led directly into the
city. This the travelers followed and before very long came to the
business district. In front of the huge cathedral they stopped to view
the crowds through the cluster of palm trees that was before them.

"Quite a bit of life here," observed Bob, as his eyes followed the
busy swarm of people. "Lima must be a place of considerable
importance."

"It is," said Mr. Holton. "It's the capital of Peru."

In the distance, beyond the plaza, a line of lofty mountains was
plainly visible in the thin air. No doubt they were many miles away.

The explorers sat down idly on the wide steps of the cathedral.

"Now," began Mr. Wallace, "we should make plans for the next two
weeks. Mr. Lewis, we know, will arrive in Mollendo in about that time.
What do you suggest doing--stay in the vicinity of Lima and take in
the sights here, or fly on to Cuzco and the heart of Inca land?"

"I'd rather stay where we are for a while," spoke up Karl. "There's so
much to see here that it will be worth it to spend a good bit of time
in this section."

"That goes for me, too," came from Joe. "We'll go to Cuzco later
anyway, so why not see what we can around Lima?"

As everyone was in favor of doing this, they agreed to find a hotel
and engage rooms.

"If I'm not mistaken, we won't regret staying in this region," said
Bob Holton.

And they did not. During the next week and a half they spent their
time taking in the sights of Lima and the rugged country surrounding
it. They visited the botanical gardens, the various plazas, public
buildings, streets, and the national museum. They toured the
fascinating country about the city, seeing the ancient Inca highway,
the mines of Morococha, the lifeless native huts that were everywhere,
the marvelously engineered railroads, and the interesting city of
Callao, located near by.

At the end of the time that they could spend here, the explorers were
well pleased with the eventful days that had passed.

"Now to head for Mollendo," said Mr. Holton, as one morning he arose
early to prepare his possessions for the trip. "We've only got about a
day before Mr. Lewis's steamer arrives from the United States, and we
must use the time to best advantage."

The others were ready and climbed into the airplane for the long
journey.

Mollendo, the adventurers found after the interesting flight, was much
like other cities they had visited. It possessed a very interesting
dock, however, which held the boys' attention for many minutes.

The following day, when it became time for the steamship to arrive,
they were on hand to meet the naturalist and the others.

"It's coming!" cried Joe, pointing excitedly toward the horizon. "And
will I be glad to see Dad!"

"I guess we all will," said Mr. Wallace.

The vessel steamed closer and headed for the port. As it came toward
them, the explorers could easily make out someone on the deck whom
they recognized. It was Mr. Lewis.




CHAPTER XIV

An Unexpected Displeasure


As the ship moved slowly into port, Mr. Lewis, standing anxiously on
the deck, caught sight of his friends and waved wildly. Obviously he
was exceedingly glad to see them again.

Others of the expedition who recognized Mr. Holton or the boys also
waved a friendly greeting, which was returned by those on shore.

When the boat had come to a standstill, a huge crane swung out and up
to the deck. At the end, attached by a massive hook, was a chair. Into
this the boat's passengers were to sit and be hoisted down to the
dock.

"Funny way of unloading passengers," laughed Bob, as he watched a
woman rather nervously sit down in the chair.

"No other way, I guess," came from Mr. Wallace. "The surf billows roll
too high for the conventional method."

The onlookers watched closely as the chair was raised off the deck
and suspended over to the shore.

The woman who was carried in this manner laughed as she left the chair
and turned to see the motion repeated. From the look on her face, it
had been an exciting experience.

"Here comes Dad!" observed Joe happily. "Wonder how he'll like it?"

Mr. Lewis had seated himself in the chair and was being carried high
in the air to the dock.

When he set foot on the ground, he rushed toward the others, on his
face a look of intense joy.

Words fail to describe the meeting that followed. Mr. Lewis was
literally mauled by his son and friends, who were overjoyed to have
him again with them. Especially was Joe happy.

"I worried from the time you left Washington," the naturalist told
them, throwing an arm over Joe's shoulder. "The more I thought about
that airplane trip the more anxious I became. You didn't have any
trouble, did you?"

"It's according to what you call trouble," laughed Bob. "If you mean
accidents, we didn't have any. But if you mean just common bad luck,
we had plenty."

"Could have been worse, though," his father reminded him. "And let me
tell you that Karl is an excellent pilot. If he weren't, we probably
wouldn't be here now."

"As if I didn't know it," smiled Mr. Lewis, glancing at the blushing
aviator. "If anyone else had offered to take you to Peru, I wouldn't
have thought much of the idea. Karl Sutman, though----"

At this moment a group of men came up, to be recognized by Mr. Lewis
and Mr. Holton.

The youths, Mr. Wallace, and Karl were introduced to them as members
of the archæological and geological divisions of the expedition. Dr.
Rust, Professors Allan and Kelley, and Mr. Dunn, as their names were,
had come to this region to search for additional Inca ruins and to
study the land in the mountain section.

Two other men completed the personnel of the expedition. They were Mr.
Buenagel, assistant, and Dr. Brown, physician, both of whom had been
on numerous expeditions with the others. They now came up and received
the same hearty welcome.

"Now that we're all together," began Dr. Rust, "we want to decide
where we'll make our headquarters. Is everyone in favor of having our
base in or near Cuzco?"

"I should say yes," came from Professor Kelley. "Cuzco, after all, is
a very strategic point, and is quite easily accessible from all parts
of this section. So why not locate there?"

As everyone agreed, the question was settled. Now came the problem of
transporting the expedition's supplies, of which there were many.

Karl generously offered the services of the monoplane in getting the
trunks and bags over to Cuzco. He explained that he would be glad to
do this for them, even though it might be necessary to make two or
three trips.

But Dr. Rust, leader of the expedition, stoutly refused.

"We don't wish to put you to that trouble," he said. "As long as there
is a railroad running up to Cuzco, we'll make use of it and have our
stuff shipped, even though it may take a few days longer."

Karl wondered afterwards if the scientist secretly feared an accident.
The tall young man remarked to Bob and Joe several days later that
perhaps Dr. Rust did not wish to take a chance on the monoplane
crashing with the expedition's supplies on board.

As had been suggested, the supplies, including those of Mr. Holton and
Mr. Lewis, were placed on board the first train that left for Cuzco.
The boxes and trunks would not reach their destination until several
days later, however, since it was necessary for them to be changed
around several times.

Except for the three naturalists, the scientists boarded the same
train for Cuzco. Mr. Wallace and the youths' fathers were to accompany
Karl and Bob and Joe in the monoplane. With Mr. Lewis in the cabin,
there would be an added load, but Karl told them it would not be
dangerous.

"Just have to watch the take-offs and the landings more closely," the
aviator explained. "Outside of that, we'll never know that another
person is inside, as far as the ride goes."

"Won't ride any easier?" queried Joe, trying to appear innocent.

"Quit your kidding!" snapped Karl with a laugh. "This bus isn't an
automobile."

"But a bus is an automobile," said Joe persistently.

He dodged a pass that Karl swung at him. Then, seriously, he turned to
the others, who were busy attending to minor tasks about the airplane.

"Everything's ready," announced Mr. Wallace, stepping inside the
cabin. "Suppose we get started at once, so as to get there and look
around some before the others arrive by train."

Karl was willing. He climbed into the cockpit and started the engine.
Mr. Holton, the last to enter the cabin, closed the door tightly just
as the monoplane began rolling over the field.

"We're off for Inca land!" shouted Bob excitedly, raising a
motion-picture camera to his shoulder. "And won't we have fun!"

"We'll also have a little work," said his father quietly. "If we get
enough specimens from this region to satisfy the museum heads we'll
have to go some."

Flying over this interesting land was exciting to the youths, who
viewed the sights curiously. Before long they could make out the town
of Arequipa away over to their right, and just behind it, El Misti
volcano, whose sides sloped up to a point.

Karl guided the 'plane as near the ground as possible, knowing that he
and his friends could not stand the rare air of several thousand feet
higher without the use of oxygen. A few tanks of this valuable gas
were now on the train en route to Cuzco. Karl had not thought it
necessary to use them in the 'plane so soon.

At the speed they traveled, it did not take them long to sight Cuzco
in the distance. Several miles away they could also see the town of
Anta, which was a mere village compared to its neighbor city.

When they came nearer, Karl flew straight for the central plaza, so as
to get a fine view of all the buildings and places of importance.

"Look at the people swarming to see us," said Joe. "I guess it isn't
often that an airplane comes here."

At about three hundred feet they soared leisurely over the central
plaza, where natives were gathering rapidly. Directly below them was
the huge cathedral, which, as far as they could see, was the most
imposing building in the city. All about were low structures, with an
occasional higher building dotting the landscape.

It was a wonderful view. Even from that low altitude, the explorers
could easily make out the surrounding mountains, on many of which were
Inca ruins, including the "staircase farms."

Joe considered it a wonderful opportunity to take several hundred feet
of motion pictures. He pointed the camera first at the city below
them, then at the near-by mountains, turning the crank continuously.

When he had flown a few times around the town, Karl picked out a level
stretch to the east and began the dangerous task of landing. Well he
knew at that altitude it would be easy to crash.

The monoplane headed downward at high speed, the wheels touched the
ground, bumped back into the air, touched the ground again. The
machine rolled ahead at fifty miles an hour, forty, thirty, and
finally came to a stop dangerously near a large pile of stones.

"All out," called Karl, when he had switched off the motor. "We're
here. And we came down without a smash-up."

Directly across the river Almodena the adventurers could see Cuzco,
looking strangely quaint in its pocket in the mountains.

"Here come more natives," observed Mr. Holton, as a horde of twenty or
thirty men, women, and children rushed toward the Americans.

As they came nearer, they uttered something that none of the newcomers
understood.

"They're speaking in Quichua--that's the native tongue in this part of
Peru," explained Mr. Lewis. "It's the same language that was used by
the ancient Incas."

Although the natives scrutinized the airplane carefully, they were not
bothersome, staring rather in awe at the great "bird" that had come
mysteriously to their city.

Karl thought it best to have the craft guarded against possible
marauders. But how he could secure a guard was a problem, since none
of the Indians could understand English or Spanish. And the aviator
knew not one word of Quichua.

"Suppose we take turns watching it," suggested Mr. Holton. "I'll take
the first watch of, say, two hours. Bob, you can take the second, and
so on until we can make some other arrangements."

"And while Dad's staying here with the 'plane," began Bob, "I'd like
to look around a bit. Anybody want to go with me?"

"Sure." Joe was anxious to see the sights in this strange land.

"Don't be gone long, boys," cautioned Mr. Lewis. "We all want to be on
hand when the train arrives from Mollendo."

The chums walked south over a level plain, hoping to see something of
interest before long.

They had not long to wait. In a little open grassy stretch beside a
wall of rock was a herd of ten or twelve llamas, grazing peacefully.
These animals were about 4 feet high, with long necks and a head like
that of the camel.

"Let's go up and see them," said Bob, moving over to the herd.

"Better not," warned Joe. "They might be dangerous."

"Dangerous? Those things dangerous? Wait a minute and I'll show you
how peaceful they are."

Bob had walked up to the foremost black animal and now began to stroke
its woolly back.

Then an unexpected and unpleasant thing happened. The llama turned
suddenly on Bob and spat violently in the youth's face.




CHAPTER XV

Attacked by Indians


Bob shook his head to rid himself of the sickening saliva. He wiped
his face with his handkerchief, with his hands, with anything he could
find. At the same time he stepped out of reach of the treacherous
animal.

When he had completed rubbing, he turned sheepishly to Joe.

"Guess I learned my lesson," he said quietly. "But who'd 'a' thought
it of the brutes?"

"Isn't wise to do anything unless you know what you're doing," Joe
reminded him.

"I've a notion to go over and wring its neck!" snorted Bob, glancing
at the llama, which had resumed its grazing as if nothing had
happened.

"Better not," Joe warned him. "You might not be able to do it. And the
Indian that owns them might come out."

"Let him come!" Bob was confident that he could manage both the llama
and the Indian.

He decided to let the matter drop, however, and continue the walk
about the plateau.

As the youths hiked farther, they passed the grassy region and came to
a higher slope that was dotted with occasional patches of cacti, thorn
bushes, and stunted trees. The Australian eucalyptus, a small tree,
was abundant.

"Can't raise anything here," remarked Bob. "Almost as bad as it is on
the Sahara Desert."

The chums made a wide circuit about Cuzco, coming in sight of the
monoplane from the opposite side.

"You're just in time to stand guard," Mr. Holton told Bob. "And while
you're doing that, the rest of us will look around a bit. We've all
been busy studying maps of the Andes."

The adventurers took turns watching the airplane and seeing the
country all during the remainder of that day. If it were able to
follow schedule, the train from Mollendo, bringing the others of the
expedition, would arrive the next afternoon.

At that time all the air travelers but Mr. Lewis were in the railroad
station waiting. Mr. Lewis had remained at the field to guard the
'plane.

"It's coming," said Mr. Wallace, and a minute later the train pulled
up and stopped.

Dr. Rust and the other scientists stepped off, to be met by the
naturalists and the youths.

"I think it might be wise," began Mr. Holton, "to establish a
temporary camp here near Cuzco, perhaps in the field by the monoplane.
Is everyone with me in this?"

Professor Allan nodded.

"I am in favor of it," he said. "Until we make further preparations
for our work in the mountains it would be wise to put up our tents
there."

At the field they found Mr. Lewis waiting for them. He also agreed to
follow Mr. Holton's suggestion.

Four tents were pitched in a semicircle beside the airplane. The
expedition's supplies were placed systematically inside, and then
began a discussion about the coming exploration.

"We who are after Inca ruins have decided to set off for the region
near Mount Panta," Dr. Rust said. "In our opinion, there is an
opportunity to find wonderful Inca remains in this section. Most
likely we will stay within twenty miles of that mountain for three or
four weeks. Where we will go then we will have to decide later."

"Now of course you archæologists want to know as nearly as possible
where we naturalists will be," began Mr. Holton. "I don't know whether
everyone will agree," he went on, "but I know of a place that
supposedly abounds with wild creatures. And I would suggest that we
head for that spot."

The others looked at him inquiringly.

"This morning while I was out scouting around I came across an
American who was just returning from a hunting trip in the Andes," Mr.
Holton resumed. "He informed me that the valley of the Comberciato is
teeming with wild game. According to his estimate, that's about a
hundred miles from here, northwest. It----"

"I've heard of it, too," cut in Mr. Wallace, his face beaming with
scientific enthusiasm. "Why not go there? We'll probably find it worth
our while."

"I'm willing," came from Joe's father.

"Then let's call it settled," Mr. Holton said. "We'll start out as
soon as possible."

"Here's where Mr. Sutman and his airplane come in," remarked Professor
Allan. "By the use of the 'plane, we can keep informed as to the
whereabouts of the other division of the expedition. It will prove a
valuable asset to our equipment."

Bob and Joe and Mr. Dunn took it on themselves to go back to the
railroad station and have the many boxes of food and supplies removed
to the camp. The scientists had purposely left them in charge of the
agent until after deciding the course of the expedition and had
carried only the lighter bags and cases to the camp.

The railroad agent, when asked of a means of transporting the boxes,
pointed outside to a large cart drawn by a mule. Walking lazily at
the side was an Indian.

"He will do it for you," the railroad man said in poor Spanish.

Then, knowing that the Americans could not speak the Quichua language,
the agent called to the native and asked if he would be willing to
take the boxes.

The Indian merely nodded and went into the building after the first
load. In all, there were about seventy-five cases, and he knew it
would be necessary to make several trips.

"That mule doesn't look any too willing to pull the load," observed
Joe with a laugh. "Be funny if he'd stop still when only about halfway
there."

When the cart was loaded with about fifteen or twenty of the boxes,
the Indian called for the animal to pull ahead. But the stubborn mule
refused to budge.

"Now what will he do?" mused Joe, looking at the impatient Indian.

He soon saw. The native removed five boxes and carried them back into
the station. Then, with the cart lighter, he again attempted to make
the mule move ahead.

But apparently it was still too much of a load, at least for comfort.

"That crazy donkey just doesn't want to go, that's all." Mr. Dunn had
been taking in the incident with a great deal of interest.

The Indian was becoming impatient. He had apparently removed all he
was going to from the cart and intended to resort to force.

Walking to one side, he pushed with all his strength on the balky
animal, at the same time saying something in Quichua that the whites
guessed was not pleasant.

Slowly, very slowly, the mule struggled forward, snorting as if in
rage. Gradually he quickened his pace, but never exceeded a walk.

"At this rate it'll take us the rest of the afternoon to get
everything in camp," muttered Bob, amused and yet angered at the
stubborn beast.

The youth guessed fairly right. The sun was almost ready to sink below
the horizon when the last box was unloaded from the cart, after five
trips had been made to carry all of the supplies.

"Too late to do anything tonight," said Mr. Lewis, as the Indian,
mule, and cart disappeared over the plateau. "I suppose we'd better
take it easy, anyway. We'll have some busy days ahead of us."

Early the next morning the explorers were up preparing for the
mountain journey.

"The first thing now is to get mules," said Mr. Wallace. "And," he
added with twinkling eyes, "they'll have to be faster than the one
that carried our stuff last night."

"You forgot." Dr. Brown, the physician, was moving up to Mr. Wallace.
"The first thing isn't to get mules," the doctor continued with a
smile. "Medical attention always comes before anything else."

"That means a physical examination?" asked Bob.

"Yes. And it also means vaccination against smallpox and typhoid
fever. Those two diseases are very common in this part of Peru."

Dr. Brown had attended to everyone but the youths and Mr. Wallace. But
it did not take long to finish with them.

"Now as I was saying," began Mr. Wallace, "the next thing is to get
mules. And I know where we can find them. I inquired yesterday and
found that a wealthy Peruvian who lives at the edge of Cuzco can let
us have as many as we need. He will also see that we get native
guides."

"Don't forget that we need about twenty-five mules--for both parties
of the expedition," Professor Allan reminded him.

"I haven't," the naturalist returned. "We can get as many as we need.
Suppose we do it now."

Mr. Wallace, Dr. Rust, and Professor Kelley set out at once to get the
pack animals.

Meanwhile, Bob and Joe took movie cameras and walked leisurely up the
hillside, intending to photograph anything that would come before
them.

The boys had not gone far when they came upon a large group of Indian
men, dressed in short, coarse trousers, hand-woven shirts, and
brightly colored blankets. On their heads were the flat "pancake" hats
which are common in this region.

"Here's a good chance to take movies," said Joe happily. He had
brought the camera to his shoulder and pointed it toward the Indians,
turning the crank steadily.

Suddenly the natives rushed angrily at the youths and made a grab at
the motion-picture cameras.




CHAPTER XVI

Just in Time


"Let go!" cried Bob, in his excitement forgetting that the Indians
could not understand English.

The group had completely surrounded the youths, and one man was
holding tightly to Bob's camera.

The two chums knew that they had little chance against so many. But
they fought doggedly to save the moving-picture machines, which were
the only two they had.

With one supreme effort, Bob pushed the Indian nearest him to the
ground and turned to find an opening in the crowd of natives.

But they were all about him, pushing and grabbing and striking to the
best of their ability. It was plain that they were determined to take
possession of the small boxes that the whites carried.

If it had not been for the necessity of holding onto the cameras, Bob
and Joe could have put up a good fight, and perhaps driven the
Indians away. But as it was they found themselves at a sore
disadvantage.

"Help!" cried Joe, raising his voice to a shout. "Help! Help!"

Several seconds later a figure showed itself at the brink of the hill
and came toward the fighting group.

"It's Dad!" Joe cried happily. "Now there'll be a fight!"

Mr. Lewis was soon joined by Mr. Holton and Karl Sutman. Like a flash
the three grasped the meaning of the scuffle and rushed to the aid of
the chums.

They dived headlong into the furious mob, using their fists to great
advantage. One big fellow Mr. Lewis knocked flat on his back in a
daze.

"Here, take my camera," directed Bob, speaking to Karl. "Run as fast
as you can back to camp. I want to take a lick at some of these
beggars."

Karl did as asked and dashed out of the mob for the tents. The last
Bob saw of him he was rounding a bend and heading toward the
monoplane.

Then Bob faced the man who had grabbed his camera.

"Take that!" the youth snarled, sending the Indian crashing to the
ground.

The other natives, seeing that they were unable to hold their own
against these whites, took to their heels and disappeared in the
distance, kicking up a cloud of dust behind them.

"Well, we licked them." Mr. Lewis was panting for breath. His face was
red from fatigue, his clothes torn and wrinkled.

And the others were no better off. They had put up a game fight,
determined to drive away their enemies.

"What was their motive for attacking you?" inquired Mr. Holton, wiping
his face with his handkerchief.

"Beyond us," Joe answered him. "We just looked at them and pointed our
cameras at them----"

"Oh." Mr. Holton seemed to understand everything. "That's all you did,
huh? Well, you did enough to excite their anger. Those natives are
decidedly against having their pictures taken. They believe that any
evil which might befall their pictures will come upon them later."

"So that was it?" Bob laughed. "Well, we'll know enough not to try the
same thing again. Anyway, we got several feet of film exposed, and
that's better than nothing."

The adventurers made their way down the hill, to be met by Karl and
the others of the expedition, who had come to learn of their friends'
misfortune.

"Quite an encounter," commented Mr. Dunn, when he was told the
details. "These Indians are bad characters when their anger is
aroused."

Back at the camp, the explorers got everything in readiness for the
expedition to depart as soon as Mr. Wallace, Dr. Rust, and Professor
Kelley returned with the mules and guides.

It was nearly noon when Bob caught sight of a long line of mules
heading toward the camp. They were coming slowly and leisurely, but
always closer. Near the rear were the three explorers and two natives,
who had been driving the animals.

"I see you met with success," said Mr. Buenagel, addressing Mr.
Wallace.

"Success is right!" the naturalist was beaming all over. "Don Chusmena
here"--indicating a small Peruvian who had been conversing with
several natives--"has generously offered to let us use twenty of his
mules. They are all fine specimens, worthy of making the mountain
trip. And the price is right."

The mules were driven up to the camp and herded together in a group.

Mr. Wallace introduced Don Chusmena to the others. The Peruvian in
turn acquainted the Americans with the Indians who were to act as
guides for the expedition. He assured them that the natives knew every
foot of ground in the Andes country. One Indian was to lead Dr. Rust
and the other scientists who were to search for Inca ruins. The other
native would guide Mr. Lewis and any others that might be in the party
of naturalists.

Both Bob and Joe had decided to stay with the expedition and not fly
in the monoplane with Karl Sutman. Mr. Holton, however, intended to
accompany the aviator and Dr. Brown, the expedition's physician. Karl
and the two men were to fly on ahead and look for Inca ruins from the
air, keeping in touch with the others. It was intended that Karl head
for the valley of the Comberciato, where he and Mr. Holton and the
physician would await the others of the naturalist party.

"That leaves you and Mr. Wallace and Dad and I together," remarked
Joe. "I'm sorry your father isn't going with us."

Bob nodded.

"He'll meet us at the Comberciato River, though," the youth said.

"But that won't be until two weeks from now, at least." Joe would have
been better satisfied if Mr. Holton had intended to go on foot instead
of in the airplane.

Mr. Lewis and Mr. Wallace desired to get their division of the
expedition started as soon as possible. But since it was so late they
thought it best to wait until the next morning.

"That'll give us time to look around some more," said Joe, picking up
a motion-picture camera. "Come on, Bob. There's a lot to be seen
around Cuzco."

"Be careful boys," warned Mr. Holton. "Don't try to photograph any
more Indians, or you may get into a bigger scrape than the one this
morning."

"Leave it to us," laughed Joe. "We'll be all right."

The youths headed west toward the river Almodena. They resolved to
cross it and proceed northward to the Fortress of Sacsahuaman and
other Inca ruins.

From the river there was a narrow road that led up the plateau to the
high hill that overlooked the city. As this hill stood between the
boys and the ruins of the fort, which were located high upon another
cliff, they found it almost necessary to climb to the top and then
down the other side.

"Now for the ruins," said Bob eagerly, pointing to the top of the low
mountain that was before them.

The youths had begun the difficult climb to the summit and had rounded
a turn in the rocks when they caught sight of an old man climbing
slowly up the dangerous ridge.

"Look!" cried Joe in terror. "He's falling!"

The old man's foot had slipped, and he was trying as best he could to
balance himself on a narrow ledge.

His efforts were in vain. The next moment he began to plunge
helplessly downward.

With the quickness of a cat, Bob stepped forward and, bracing himself
as best he could, he threw himself against the man. The impact of
Bob's heavy body stopped the man's fall and sent him against the side
of the cliff. It bruised his face and shoulders, but he was safe.

After a few moments of resting, the old man looked up, wild-eyed and
white with fear. There was an expression of intense gratitude on his
wrinkled face as it was turned toward Bob.

"You saved my life!" he cried in excellent English, gazing fearfully
below. "And I want to reward you. I want to tell you of some Inca
secrets--secrets of the Andes!"




CHAPTER XVII

The Old Man's Tale


At once Bob and Joe were breathless with interest. They had often
heard of Inca secrets but had thought them nothing more than myths.
Now, as this strange old man stood before them, the youths wondered if
there might have been some truth in the fantastic tales told of Inca
mysteries.

The old man hesitated for several minutes, staring off into space.
Then, when the youths were becoming impatient with the long silence,
he continued, speaking in a low voice.

"Far, far away, in the heart of a huge mountain, is a narrow tunnel
that leads to a large cavern of Inca secrets." Again the stranger
hesitated, looking below at Cuzco.

"Why doesn't he hurry?" thought Joe, almost saying the words aloud.

Finally the old man continued.

"This cave is so large that it occupies the entire mountain," he went
on. "It is lighted with a strange brilliance, that comes mysteriously
from the outside. But ah! The Incas were marvelous inventors. They
could do many things that we Americans cannot do."

"Then you are an American?" inquired Bob quickly.

The old man nodded.

"I spent my early years in the United States," he explained.
"Graduated from college and set out to be a scientist. Then I became
interested in Inca ruins and came here to look for them. My entire
lifetime I have spent in these mountains, looking for ruins and
treasure."

"Treasure?" cried Joe. "Is there treasure here?"

"Undoubtedly there is," was the answer. "In fact I believe I have
found some."

The young men were all excitement.

"Tell us about it!" begged Joe.

"I am not certain that I have found any," the stranger said. "But I
came across a sort of bin that is covered with a heavy stone block.
Alone I am not able to lift it off. I firmly believe that in the bin
is something valuable. This is in that cave I told you about." He
stopped and glanced about; then, satisfied that no one else was near,
he continued: "It is a long, hard journey to this wonderful place.
There is a secret trail, that is known only to myself. And to add to
that, there is a single entrance to the cave. It cannot be opened
until you press a hidden button."

He stopped a moment and gazed thoughtfully at the young men.

"You saved my life," he went on, looking at Bob gratefully. "For this
I will gladly give you half of any treasure in the bin, if we can find
any. Will you make the trip with me?"

For a few moments the youths said nothing. They wondered if there was
really any treasure in the bin. And they wondered, too, if it might be
possible to locate still more in the near-by mountains.

"I am willing to go," said Bob at last. "It won't put us out any, I'm
sure. I think we can arrange it some way. Maybe Dad----"

He got no further, for at that moment the old man raised a hand for
silence.

"Of course your dad is all right," he said conclusively. "But I do not
wish to take anyone but you and your friend here with me. Even your
father might without thinking tell someone about this secret, and then
we would lose everything. And I want no one else to know."

"Then," began Bob, "you want only Joe Lewis here and myself--my name
is Bob Holton--to go with you?"

"You are right," came the reply. "And my name is Rander--_Doctor_
Rander. I would be much better satisfied if only we three went."

"I think it can be arranged," Bob told him. "What direction do we have
to go?"

"East. Almost straight east from Cuzco. But of course there are many
roundabout paths that we must follow, and much of the way is over no
trail at all."

"We'll let you know a little later, if that is all right," said Bob.
"Where can we get in touch with you?"

Dr. Rander explained that he was staying in a little adobe hut at the
other edge of Cuzco and that he had a sufficient number of mules to
carry the provisions needed.

"How soon do you want to start?" inquired Joe, who was anxious to make
the trip.

"I am ready any time," the old man said. "If you wish, we will start
tomorrow."

Bob explained that they would talk it over with their fathers and call
on their friends that night. With this, the youths headed back to
camp, not desiring to lose more time even in seeing the ruins at the
top of the hill.

"What do you think of it?" asked Bob a little later, as he and his
friend came in sight of the monoplane.

"I think a lot of it," Joe answered. "Why, it will be wonderful!"

"Don't be too sure that we can go," Bob reminded him. "It all depends
on what our dads think. If they're afraid to let us leave the
expedition and start out with this Dr. Rander, why, I suppose that
will end it all. And the old man won't let anyone else go with us."

"Funny he'd tell us about that secret, isn't it? If he had kept still,
he'd have had all the treasure for himself. But then, I suppose he was
so glad you saved his life that he was more than willing to let you in
on it. Then, too, he's not sure of finding it."

At the camp, the boys found their fathers and others awaiting them.

"What do you think of the ruins?" asked Mr. Holton, as the chums came
up.

"We don't know much about them," returned Joe. "But there's something
else we want to tell you."

While the men listened, Joe told of seeing the old man climbing up the
steep hill and of Bob's saving his life when he fell. He told of the
secret treasure that the stranger said was in the Andes, and of the
old man's desire for the two youths to accompany him in the mountains.
He finished by saying that he believed it might be worth while to go.

"Perhaps you're right," came from Mr. Holton. "It might pay you to go
with him. Do you think he can be trusted?" Mr. Holton had great faith
in the judgment of his son and Joe.

"Don't know why not," said Bob. "He seemed so glad that he had not
fallen down the cliff that he was happy to tell us about the
treasure."

"There isn't a chance of his being crazy, is there?" asked Karl
Sutman, who was also listening to the conversation.

"Oh, of course there's a chance," replied Bob, "but I'd be willing to
bet anything that he isn't."

"We can go with him, can't we?" queried Joe, glancing especially at
his father. "We may find treasure, after all."

"I see no reason why you shouldn't," came from Mr. Lewis. "Of course
you'll be careful. And there's very little danger of getting lost,
with all the native huts scattered about. What do you think, Howard?"

"Like you," Mr. Holton replied. "After all, Bob and Joe are able to
take care of themselves. If Karl will stay in the vicinity of Cuzco
until they get back, it will ease matters some. Or, if the boys will
be gone too long, Karl can come on with the rest of the expedition to
the valley of the Comberciato, and then return later to pick up Bob
and Joe in Cuzco."

"I'll be glad to do it," Karl Sutman said, and so the matter remained
settled.

That evening Bob and Joe went to Dr. Rander's hut at the edge of
Cuzco. The old man seemed glad to see them, offering them the best
chairs he had.

"Now about the secrets," he began, after he had closed the door and
made sure that no one was near. "First of all, we must keep it
strictly to ourselves. If, while on our way, anyone should ask why we
are going into the mountains, we must not tell them."

"For one thing, we're going to take movies of the country," said Joe,
and then explained this in full to the old man.

The youths spent all evening at the old man's hut. When at last they
were ready to leave, they had agreed on one thing: They were to start
early the next morning.

As they walked silently back to the camp, gazing up at the starlit
sky, Bob and Joe wondered what would be their adventures for the next
few weeks. Would they actually come into possession of valuable
treasure?




CHAPTER XVIII

Starting Into the Mountains


Early the next morning the youths were up getting ready for the long
journey into the unknown. They had all their possessions packed when
Dr. Rander came with mules and provisions.

He was introduced by Bob and Joe to the other members of the
expedition, who, particularly Mr. Holton and Mr. Lewis, recognized him
as a capable explorer.

The youths made arrangements for Karl Sutman to meet them in a town
called Pasaje, at the end of a sufficient time. The aviator was to
have his monoplane ready to take the youths to the locality occupied
by other divisions of the expedition.

"Now do be careful and don't take any chances," warned Mr. Holton,
after additional boxes of food had been strapped on the backs of other
mules. "Remember, slow traveling with safety is far better than rapid
going with danger."

"We'll be all right," Joe assured him, as the mules were being placed
in line. "And Karl will fly us to your locality in due time. Don't
forget that you are to be careful too."

With fond farewells, Bob and Joe and the old man drove the mules
toward the rim of mountains that skirted the eastern horizon. They
rounded a high hill and lost sight of their relatives and friends.

For some time the youths were silent with their thoughts. Who knew
whether they would ever see those dear ones again? Even at best, there
were untold hardships and dangers in the mountains that lay before
them. Would they be able to meet any crisis?

It was some time before the boys resumed their natural peace of mind.
But when they did, they were eager to take in all the sights of this
wonderland.

There was a wide trail that led eastward from Cuzco. Over this the
pack train went at a slow but steady gait that promised to eat up the
miles sooner than it might be thought possible.

"Wonder if we'll see any big game?" remarked Bob, as he and Joe walked
near the rear of the pack train. "I'd like especially to bag one of
those white condors Dad was talking about. You think there are any?"

"Possibly," replied Joe. "But if there are, it isn't likely that we'll
see one."

The three adventurers followed a well-beaten path to the town of
Puquiura, which they found nothing more than a group of native mud
huts.

"Not much life here," observed Joe, as the caravan of pack animals
passed on through the village.

"I suppose this is typical of all the towns in these mountains," came
from Bob. "Just a bunch of dirty mud dwellings."

Led by Dr. Rander, the Americans wound around a narrow trail that
reached steadily upward. They were making fairly good time, and if
nothing prevented, they expected to arrive at a much larger town
before noon.

"I think I'll try riding my mule," announced Bob, who, along with his
friends, had been walking beside the mounts.

"Better watch out," cautioned Joe. "Those little animals are
treacherous sometimes."

Bob called to Dr. Rander to wait for him. Then, pulling his mount out
of the line, he placed his foot in the stirrup and threw his leg
across the sturdy little mule's back.

But just then something happened. The animal wheeled about, and,
throwing its hind feet high in the air, it leaped forward with a snort
of resentment.

"Help!" cried the amused and yet worried Bob.

"What do you want me to do?" inquired Joe, taking in the scene with
interest.

"Grab hold of his tail! Do anything!" Despite his serious predicament,
Bob could not help laughing, although he was angered.

"Get hold of his tail, huh? Not much." Joe intended to derive as much
amusement as possible from his friend's plight.

All joking was cast aside a moment later when, at an unexpected
moment, the mule gave a quick turn to the left and threw Bob to the
ground. The youth caught the fall with his arm, and so escaped injury,
but his anger was as strong as ever.

"I'll fix you, you----"

Bob did not finish the words, for at that moment the mule leaped
forward and galloped off at a rapid pace.

"After him!" Bob cried, dashing ahead as fast as his legs would carry
him.

A more amusing sight could hardly be found. Joe's laughter mingled
with the sound of rapidly moving hoofs, and even old Dr. Rander joined
in the merriment.

"Think he'll catch him?" queried Joe, as pursuer and pursued vanished
behind a heavy cloud of dust.

"I believe so," the old man returned, straining his eyes to make out
the figures ahead. "The mule will soon tire of such fast running. He
isn't used to it."

Dr. Rander was right. Five minutes later Bob appeared from around a
hill leading the now calm animal. There was a smile of triumph on the
youth's face as he faced his friends.

"Now that everything has worked out all right, suppose we forget that
anything happened," grinned Bob, as he placed the mule back in the
line.

"You going to try riding him again?" asked Joe with a laugh.

"Not on your life. I value my hide too much for that."

They set forward, heading for the distant high peaks, which were
always visible.

An hour of steady climbing brought them to a high plateau, which was
bordered by mountains. From this elevation the explorers could command
a good view of Cuzco, which seemed but a miniature city in the
distance.

"I don't feel so well," groaned Bob, whose face was becoming pale. "I
can't get my breath without wheezing. And my stomach seems out of
order."

Dr. Rander happened to be near when Bob complained, and lost no time
in attending to the youth.

"You probably have _soroche_, or mountain sickness," he said, noting
that Bob's pulse was unusually rapid. "Do you think you can keep on to
the next town?"

"Sorry, but I'm afraid I'll have to lie down somewhere." The stricken
Bob was visibly becoming worse with every minute.

"Wonder if I'll have another touch of mountain sickness?" mused Joe,
as his friend stretched out on a blanket that Dr. Rander had spread on
the hard ground.

There was nothing to do but wait for the youth to recover. The old man
explained that often patients remained ill for several days, and that
there was a possibility of Bob's sickness being lengthy.

In view of this, they thought it best to make camp and prepare to stay
as long as necessary. There was no use making arrangements to continue
the journey until Bob's condition improved.

"Here, take this pill." Dr. Rander held a little white tablet and a
cup of water. "It will make you well sooner than anything else."

But it was not soon enough for Bob. All the remainder of that day he
moaned on with a splitting headache and terrible nausea. It was worse,
he said, than sea sickness, of which he had experienced a touch on his
first ocean voyage.

The next morning, although still weak, Bob was greatly improved. The
ill effects had gone, and once more he had an ambition again to get to
the trail.

But Dr. Rander protested.

"You are not strong enough yet," he said. "We'll wait till noon and
see if you're improved sufficiently by that time."

By the time the sun was directly overhead, Bob was his old natural
self again. He was overly anxious to make up for lost time.

Lunch over, the explorers again took to the trail, driving the staunch
little mules along at a rapid pace.

"Now lead me to those secrets of the Andes!" said Bob, as Cuzco faded
from view.

At length the adventurers came to another town, which Dr. Rander
called Cameras. They would much rather have encircled the settlement,
but as there was no other trail, they passed on through.

"Let's leave the mules here near the edge of town," suggested Joe.
"I'd like to go back to that little store that we just passed. Might
be able to get something we can use cheap."

"I'll go with you," said Bob.

Dr. Rander announced that he would stay with the mules and catch a
short rest. He cautioned the boys not to stay too long.

The store that Joe referred to was nothing more than an adobe hut
filled with curios of the Andes. They purchased a few articles as
souvenirs and started back to the edge of town, where the old man was
waiting.

Suddenly there came the sound of rough voices, and a moment later a
dozen shots rent the air.




CHAPTER XIX

A Terrible Sight


"What's going on?" cried Joe Lewis, as a chorus of voices mingled with
the sound of rifle shots.

"Some trouble somewhere," returned Bob. "Wonder----"

He did not finish, for at that instant there came another shot, and a
bullet whizzed by his ear.

The youths lost no time in hiding behind a small mud hut, although
they knew a bullet could probably penetrate it. But at least it
offered temporary shelter, and that was what they wanted.

"Look!" cried Bob, gazing cautiously around the corner of the hut.
"There are soldiers in uniform. What do you suppose they're doing?"

They were soon to see.

The troops, which numbered about thirty, were firing at something that
the boys could not see from their places at the side of the hut.

"I'm going to take a chance and get out in the open where I can see
something," said Joe. "Come on. If we're careful and don't get in the
way of the shooting, we'll be all right."

Carefully the chums edged around the side of the dwelling and peeped
out at the street. Then they drew back quickly, as a score of shots
rang out.

What the youths saw was forty or fifty natives scattered out to escape
the fire of the soldiers. Each held in readiness an old rifle, which
he discharged at intervals.

"Must be a revolution," observed Bob. "Perhaps those natives have
offered violence to the governor of the town, and the troops have been
called to settle the matter."

Bob could not have come closer to the facts.

"The soldiers are winning," said Joe. "They're better trained and have
more efficient guns."

Although the troops appeared to gain the upper hand, the fighting
continued with as much fury as before.

A sudden fusillade of bullets coming dangerously near Bob and Joe
prompted the boys to make a dash toward the end of the town, where the
mules and Dr. Rander were probably waiting.

"Let's get out of here," suggested Joe. "We'll get hit if we don't."

"All right. Wonder if Dr. Rander is still where we left him?"

The chums were greatly surprised when, a few minutes later, they saw
that the old man was not in sight. But the mules were tethered to a
stout post, and this gave the boys hope.

"Chances are, he's gone to see what the shooting's about," Bob said.
"Wish he'd come back. He's likely to get killed if he stays around
there close."

The youths were beginning to worry when Dr. Rander appeared up the
road, glancing occasionally over his shoulder.

"Quite a commotion, wasn't it?" he said when he had come nearer. "But
the soldiers drove them away."

"What was it, a revolution?" inquired Joe.

"Yes. An Indian told me that the people in the town were turning
against their prefect. Didn't like his rule, and wanted a change. But
the soldiers soon fixed them."

"Is the fighting over?" Bob had not heard a rifle shot for several
minutes.

"Yes. The soldiers forced the citizens to throw away their weapons."

"And that reminds me," laughed Joe. "We'd better be getting our rifles
out, because we may see some game before long. I'd like to get a shot
at a condor."

"Condors live only in high mountains," explained Dr. Rander. "We
won't see any for many days, if at all."

But although the adventurers did not catch a glimpse of these huge
birds, they saw occasional small animals, such as rabbits and
chinchillas. Once Joe took a shot at one of the latter creatures, but
his aim was not steady and he missed.

At noon that day they came to a small adobe hut, from which hung a
green wreath.

"What does that stand for?" asked Bob innocently. "Is somebody dead?"

For the second time since the youths had known him, old Dr. Rander
burst out in laughter.

"Hardly," he said finally. "A green wreath means that bread is for
sale."

Joe almost choked with laughter.

"That's a good one on you," he said to his chum. "It's a wonder you
didn't go and gather flowers and offer them to the bereaved family."

Bob grinned.

"You'd probably have asked where the corpse was," he said. "Or
maybe----"

"We can stop here for a meal," Dr. Rander interrupted. "It is best to
save our provisions as best we can, because later on we won't be able
to find any native huts."

Inside the mud building, the three were waited upon by a huge Indian
woman, whose hard face inspired no trust from the explorers. But they
were glad when she spread before them a bountiful meal of potatoes,
roast mutton, and a drink which the youths guessed was intoxicating.

"None of that brown liquid for me," came from Bob, looking with
suspicion at the huge clay cup that contained the beverage.

"Me either," echoed Joe. "Too big of a risk."

The old man, however, drank freely of the beverage and seemed pleased
with its flavor. Whether he knew of its ingredients the chums did not
know.

As soon as the meal was over, the three again took up the journey,
keeping a sharp lookout for anything that might prove of interest.

They found something before they had gone another mile.

Coming up the trail at a slow, leisurely gait was a large donkey, on
the back of which rode an Indian man, woman, and two half-grown
children. But something else amused the chums more. In pouches secured
to the mule's sides were two other Indian children, their faces sober
as they looked upon the whites.

"Where's a movie camera?" demanded Bob quickly. "I'm going to take a
chance with them. They can't do anything to us."

"Here." Joe had removed a camera from his pocket and was turning the
crank and exposing several yards of film. "This ought to be
interesting on the screen," he said.

Much to the youths' surprise, the Indians did not protest at having
their pictures taken. They merely stared at the whites in wonder.

"Maybe they haven't seen a camera before, and don't know what it's all
about," was the opinion expressed by Joe.

A little later they came to a flat field, which was being cultivated
by an Indian with a team of oxen and a crude wooden plow. It was an
interesting sight. The slow animals drew the improvised instrument
steadily through the hard soil, while the sober Indian watched
closely.

"More movies," sang Bob, bringing out his camera. "Every little bit
counts."

Again they were surprised to see that this Indian displayed no
indignation at the whites taking pictures. Perhaps after all Joe was
right and the Indians in this section were not familiar with a camera.

The adventurers had been driving their pack animals ahead all
afternoon when suddenly they rounded a bend and came to a narrow
river.

"Look!" cried Joe quickly, pointing ahead. "What's that on the bank?
Why, it's bones!"

Dr. Rander had heard.

"Llama remains," he explained. "Looks like llamas have picked this
spot to die on."

Scattered thickly over the river bank were scores of white bones,
which undoubtedly were those of llamas.

"I knew elephants occasionally have a cemetery, but that any other
animals do I had not the slightest idea," said Joe.

More movies were taken, and then they set about to devise a means to
cross the river.

"We'll have to ford it," announced Dr. Rander, who had been waiting
for the chums to walk on up to the head. "I don't think it is so deep
as to cause us trouble."

Although the weather was warm, Bob and Joe chose to put on their hip
boots, to escape the chill that might otherwise result.

They found that Dr. Rander was right. The river was barely three feet
deep and was comparatively calm. So they had little difficulty in
driving the mules across.

From the opposite bank two trails branched off up the mountainside.
The one that was most difficult to follow, Dr. Rander chose.

"From here our going will be more arduous," he told the young men.
"The mountains are steeper, and more obstacles will stand in our
way."

Bob had followed the pack train to a height where he could command a
good view of the surrounding country when suddenly he cried out in
pain.

"My foot!" he groaned, when the others rushed to his side. "Something
bit it."

"What was it? A snake?" Joe demanded anxiously.

"Let me have a look at it," the old man said, tying the foremost mule
to a gnarled tree.

When Bob removed his legging and sock, he found a large red scratch,
and the flesh about it was already badly swollen. It pained severely
and throbbed so violently that the boy could hardly hold his foot
still.

"Not a snake," Dr. Rander told him. "Rather a poisonous insect--they
are common in the Andes."

The old explorer bathed the foot in water from a canteen and treated
it with antiseptics, wrapping it up firmly.

"Now until that heals some you'll have to ride your mount," Dr. Rander
said. "Don't take no from him for an answer. Get on him and make him
carry you forward."

While Joe and the old man held the mule securely, Bob mounted and with
drawn reins held the animal at a standstill.

"Hurrah!" yelled Joe. "You've made him give in."

"Not altogether," Bob said. "But I think I can manage to stay on."

At the end of two days of riding the mule, Bob was convinced that the
animal was not really as balky as he had at first supposed. Over high
hills and rocky paths he carried his rider, until at last Bob's foot
became well enough for him to walk.

"I'll sort of hate to do it," laughed the youth, when they were camped
under a high overhanging rock.

"I know," said Dr. Rander. "But there isn't much choice in the matter.
After all, our mounts are not to be ridden except in such an emergency
as this. They tire too easily when on the rocky trails, and it isn't
best to put much of a load on them."

On, on the little party plunged, into the heart of the mountainous
region. On every hand they saw something to hold their interest.

They had been on the trail about four days when they saw something
that was indeed unusual.

Moving leisurely up the narrow path were eight or ten large Indians
carrying an old organ. Ropes were tied tightly around the instrument,
and to these the Indians held with a death grip.

Where they were taking the organ, the whites could only guess. Perhaps
it belonged to a plantation owner, who wanted a musical instrument in
his house.

Suddenly, unexpectedly, one of the Indians cried out in fright, and
then there came other cries.

"The organ's slipping!" shouted Joe. "It's going over the cliff! And
oh!"--he gasped for breath--"it's taking one of the Indians with it!"




CHAPTER XX

Difficulties of the Trail


The sight that the explorers beheld was unpleasant to the extreme.
Scarcely had Joe uttered the cry of horror when the organ suddenly
fell, pushing one of the natives over the cliff.

The man screamed in terror and then disappeared into the depths below.
It was thousands of feet to the bottom of the abyss, and instant death
was almost certain.

Bob drew back from the brink with a shudder. Joe and Dr. Rander gave
cries of repugnance. The other Indians screamed hoarsely, uttering
something that only Dr. Rander understood.

The natives ran wildly down the trail, scowling and making gestures.

"Terrible!" muttered the old explorer, when they had disappeared
around a turn.

"What did they say?" inquired Joe, who had been struck by the Indians'
attitude of anger.

"They intend to kill the man who wanted the organ," Dr. Rander told
him. "They blame the Indian's death on him."

"Well, of all things!" exclaimed Joe indignantly. "Isn't there
anything we can do about it?"

The old man shook his head.

"When they set their minds on anything there's no use trying to change
them," he said hopelessly.

"We might warn the man whom they intend to kill," suggested Bob
Holton.

"Don't know who it is," Dr. Rander returned. "And the Indians wouldn't
tell us."

Bob and Joe all during that day felt that something could have been
done to prevent the natives from killing the plantation owner, or
whoever it was that was getting the organ. They were not a little
vexed at Dr. Rander for treating the matter so lightly.

"But then," said Bob hopefully, "maybe the Indians didn't get away
with it."

Ten minutes later the youths forgot about the incident. They had been
struggling over an exceedingly rough stretch when they suddenly came
to another river, much wider than the one they had seen several days
previously.

"Have to ford it, I guess," said Joe Lewis. "No other way across."

Again the boys put on their hip boots, and again they plunged into the
water, driving the mules before them. The going here was difficult,
as the current was rather strong, and the mules had to be watched more
closely.

They were about halfway across when the old explorer cried out in
fright.

"Help!" His voice was wild with terror.

"What is it?" demanded Joe, who was nearest him.

Then the youth saw. Dr. Rander was rapidly sinking into a hole.
Already the water had reached his chest, and he was going down
rapidly.

Joe at once put thought into action. He dashed over to one of the
mules, opened a bag, and began searching about for a rope.

Frantic with the delay, the youth worked his hand like a machine,
feeling in every corner of the bag. What if he could not find the
rope?

But fortune was with him. In another bag on the opposite side of the
mule he found the rope. Luckily it was not tangled.

Joe was almost afraid to turn for fear Dr. Rander would be gone. His
heart gave a leap as he saw that the explorer's head was still above
the water.

"Here, get hold of this," Joe called, throwing the rope over to the
old man. "Now come on, Bob. Let's pull."

This last was unnecessary, as Bob was already on the spot waiting to
catch hold of the rope.

"Steady, now!"

Slowly the youths pulled their friend out of the heavy mud, which
oozed ominously as it released its victim. Once it seemed as if the
old man would have to release his hold, but he managed to hang on
desperately.

At last, when he was completely out of the mud, he moved over to his
young companions and gazed at them gratefully.

"You did wonderful," he commended. "Many people would have acted more
slowly--and I would have gone under."

"Wonder if there are any more treacherous places like that?" Bob
scanned the chocolate water closely, as if by instinct to detect any
dangerous spots.

"We'll have to risk it," Joe said. "It might be well to spread apart,
so if anyone gets caught, the others can come to his rescue."

"Good suggestion," praised Bob. "I'll get away over to this side."

But if there were any more mud holes the explorers failed to come
across them, and finally reached the other side safely, driving the
mules before them.

On the bank Dr. Rander took off his mud-soaked clothes and replaced
them with dry ones. Then, after a short rest, they resumed the
journey.

"Who's coming?" Joe strained his ears to make out the source of
footsteps.

Then, rounding a growth of stunted trees, appeared a long caravan of
small llamas, which were heavily loaded with what was probably
firewood. Beside the curious animals walked two Indians, wearing the
common "pancake" hats.

Luckily there was enough room for both cavalcades to pass freely, and
they experienced no difficulty.

The natives stopped for a few minutes and conversed with Dr. Rander,
who spoke Quichua freely. Then they started down the trail, driving
the llamas at a rapid pace.

"Funny animals," observed Bob when they had gone. "I was afraid all
the time one or two would come at me and spit in my face, like the one
back at Cuzco."

Joe laughed.

"As long as you don't bother them, I guess they're all right," he
said. "But from what I've heard, they don't like to be played with."

"Don't I know it!" grinned the other youth.

Before long they saw the origin of the llama caravan. Set back from
the path was a large mud hut, about which played several Indian
children. Another man and a woman came out to meet the adventurers.

Again Dr. Rander stopped to converse in the Quichua tongue. But not
for long. He was anxious to lose no time in getting to the secrets.
Even at best it would require many, many days.

"Hope we don't have any trouble from now on," said Joe, as he followed
the old man up a steep slope. "But I suppose we will."

Bob nodded.

"Exploring has its difficulties," he said. "It will be funny if we
don't have any more things happen to delay us."

That evening they camped in a little valley between two high peaks.
All were glad to rest their tired limbs after such an arduous day over
rocky paths.

At a small gurgling spring but a short distance away they drank freely
and filled their canteens to capacity. Then, refreshed and ready to
prepare the meal, they were about to head for the tent when Dr. Rander
noticed something coming at them. He turned about quickly, his face
white with fear.

The youths saw the danger and ran toward the mules as fast as they
could.

Advancing toward them was a heavy swarm of green jungle flies, whose
bite all knew to be poisonous as well as annoying. If the flies
attacked the explorers, the result would be marks and red, swollen
scratches that would disappear only after several weeks of patient
treating.

"The mosquito nets--quick!" cried Dr. Rander, opening a pack and
fumbling about nervously. "We must have them! That swarm of flies is
so large that there won't be anything left of us!"

But the adventurers were not quick enough. Before they could get out
the nets the buzzing flies were upon them, biting their faces and arms
severely. The little insects even penetrated the heavy clothing in a
determined effort to satisfy their thirst for blood.

"This is awful!" groaned Bob, working feverishly to find a net.

Scarcely would they put a hand into the packs when they would have to
remove it and slap away the flies, the marks of which already pained
severely.

At last Joe found the pack that contained the nets, and lost no time
in distributing the latter among his friends and himself.

"Now let them come," challenged Bob, facing the swarm angrily. "I
guess it won't do 'em any good now."

But even with the protection afforded by the closely woven nets, the
menacing little creatures bit the explorers' arms and legs most
annoyingly.

Relief did not come until dark. The blackness of the night served in
some manner to cause the flies to leave, although a small few remained
threateningly.

"Oh!" muttered Bob, trying in vain to bend his wrist. "They sure fixed
us up plenty good. Our---- My gosh! Joe, look at yourself in a mirror.
And you, too, Dr. Rander."

The three were indeed a sorry-looking sight. Their faces were so
swollen that their eyes were hardly visible, and their hands and arms
were no better off.

"And how it hurts!" Joe was almost frantic with the stinging pain.
"It's a good thing the sun went down when it did, or there would have
been nothing left of us," he added.

All were too bruised and tired to prepare a meal, but necessity forced
them to do so. But not until Dr. Rander produced a large tube of a
special salve, which he applied freely to the swollen parts.

"This will relieve the pain," he told the youths. "In the morning
we'll be a little better, but it won't be for a week that the sores
will disappear completely."

Dawn found the adventurers scarcely aware that they had been bitten,
although the scars were still there to tell the story.

"Let's forget all about that unpleasant encounter," suggested Joe
optimistically. "Suppose we take everything that happens purely as an
adventure."

"Now you're talking!" Bob patted his chum on the back. "We came here
for adventure, and we mustn't kick when we get it."

Along toward noon Bob was lucky in bringing down a wild duck, which
flew from a jungle not far away. Roasted over a fire, it proved good
eating, despite the fact that it was tough.

Dinner--for that was what the youths called the noon meal when they
were on exploration trips--over, they took it easy in the shade of a
group of stunted trees, which grew almost straight out from the
mountainside.

"Trail's pretty bad," observed Joe, his eyes on what could be seen of
the narrow path as it circled up the peak. "But I suppose it's nothing
to what we'll find it later on."

Which proved fairly accurate, as they later observed. At times the
trail was so rough and rocky that it was with greatest difficulty that
the mules were able to clamber up the steep elevations. On one
occasion it was necessary for the mules to jump up a three-foot rock,
which obstructed the trail dangerously near a five-hundred-foot drop.

"Steady, now," cautioned the old man, helping the youths unload the
mules. "If we make a misstep, it will prove our finish."

None of the explorers did, fortunately. But one of the mules was not
as lucky. It was the last animal in the line and had been carrying
only trifles that were not of necessity to the explorers.

The other mules had safely jumped to the top of the rock and were
grazing on the thin patches of grass that grew on the mountainside.

"Hurry, now," came from Joe. "Let's get this last fellow up."

Scarcely had the words left his mouth when the unfortunate animal lost
its footing and, balancing for a moment at the edge of the canyon,
plunged helplessly over the brink.

"Gone!" Dr. Rander could hardly believe the fact.

Bob and Joe had watched the accident tensely, unable to render any
assistance to the terrified mule. At last they climbed up on the rock
with a resolution to take matters as they were.

"Talk about adventure," said Bob with a grim smile. "I guess we're
getting plenty of it."

"Just wait," murmured Joe meaningly. "This won't be anything to what's
coming, or else I'll miss my guess."

"I sincerely hope nothing else will happen today," Dr. Rander said. "I
wish to get beyond this short range of mountains before nightfall."

They later saw that traveling was so slow that it would be impossible
to do this. But they were well on the other side of the peaks when
darkness overtook them.

"Now to make camp," sang Bob, tethering the foremost mule to a stout
crag.

"Wait," called Joe, who was just out of sight around a turn.

"What for?"

"Because--I've found something. Come here."

Bob and Dr. Rander went around the bend, where Joe was waiting for
them.

"It's a cave," explained the youth. "A big cave. Let's see what's in
it."

"Better be careful," was the old man's warning. "It isn't unlikely
that some snake has its lair here."

They went in cautiously, Joe holding his flashlight and Bob his
revolver. How far the opening extended they had not the slightest
idea, for the light beam did not reach the other end.

Suddenly Joe shrank back, as his light rested on something not thirty
feet ahead.

"Bats!" he cried. "Vampire bats! And they're coming toward us!"




CHAPTER XXI

Danger at Hand


Turning on the moment, the three ran toward the entrance of the
cavern, never looking behind for fear of seeing the ugly creatures
dangerously near.

"They're coming!" panted Bob, as he heard the flapping that told that
the bats were flying nearer. "And I do hope we can get out in time!"

They reached the entrance of the cave and dashed out, but not before
one of the creatures had inflicted an ugly bite on Dr. Rander's leg.

Once out of the dark opening, the adventurers felt fairly safe, even
though several bats followed them.

"We can at least fight them off out here," said Joe. "And that was
something we couldn't have done in the cave."

The several bats fluttered about ominously, keeping close to the
ground. Their faces were of peculiar shape, closely resembling that of
a bulldog. What interested Bob and Joe was that the creatures could
run very rapidly over the ground.

"Usually bats can't make much speed except in the air," remarked Bob,
remembering something his father had told him. "Their legs aren't
ordinarily made for walking."

"It's different with these vampires, though," came from Joe.

Dr. Rander thought it best to proceed farther before making camp, in
order to protect the pack animals from the bats. He well knew that it
is not uncommon for mules and llamas in this region to be attacked by
bats. People, however, are usually safe from their bites.

That night the mules were molested only slightly by a few of the bats
that followed the expedition. But aside from a few swollen places,
they were none the worse for their experience.

"It's a wonder one of us hasn't a place or two to show that the bats
were around," remarked Joe, after, the morning meal.

"We have." Bob glanced at the old explorer. "At least Dr. Rander has."

That person had been treating the wound in his leg and watching it
closely to see that infection did not set in. The right kind of care,
he said, would cause the sore to heal quickly.

Again up the difficult trail the explorers went, after having broken
camp and attended to the mules.

"Wouldn't be funny if we'd meet anything here," said Bob with a
shudder. "The path is so narrow that it's all we can do to get by
ourselves."

"No," Bob agreed. "And there's no way of telling----"

He did not finish the sentence, for at that moment there came a
commotion from around a turn. To the travelers, it sounded like
rapidly moving hoofs.

The noise increased. Then the three shrank back as they saw advancing
toward them a line of galloping vicugnas, which were small animals
resembling llamas.

Joe groaned hopelessly.

"Either we or they will have to go off the cliff," he said tensely.
"There isn't room for both of us."

The animals came nearer at a rapid pace. Apparently they were greatly
frightened from some cause or other. Whether something was chasing
them the travelers did not know.

"We must save the mules!" cried Dr. Rander anxiously.

"I have an idea, if it will work," said Bob.

The other looked at him hopefully. Well they knew that if the pack
animals were to plunge over the edge of the peak, the three would be
faced with the possibility of starvation.

There was not a moment to lose. Whatever they did must be done
quickly.

Bob moved over to the head of the pack train. Joe and Dr. Rander
remained near the middle of the line, intending to frighten the
vicugnas and prevent the pack animals from becoming panic-stricken. If
necessary, they would shoot the vicugnas to prevent them from coming
around the trail. But unless forced they did not wish to do this for
fear of scaring the mules.

In front of the foremost pack animal Bob stood with a thick rope,
which he had formed into a lasso. When the first vicugna came near,
the youth swung the loop out from the side of the mountain and made a
perfect throw over the animal's head.

Bob gave the rope a quick pull and then let go. The impact brought the
vicugna to the ground with a thud. Its followers, trying in vain to
check themselves, stumbled over their fallen leader, several of them
falling over the cliff. The others remained on the trail with
difficulty.

"Fine work!" praised Joe, walking around the mules to his friend. "If
you hadn't thought of that, I guess we'd have had to shoot them. I
didn't know you knew anything about a lasso."

"I don't. That is--very little. But I thought I'd try that and see if
it would work. If it didn't, I was going to shoot them. They had to be
stopped some way."

"What do you suppose made them come around the trail so fast?" asked
Joe.

Dr. Rander expressed the belief that the vicugnas had been frightened
by a puma or some other animal.

"Otherwise they would not have made that wild dash," he said.
"Whenever you see a stampede of animals, you may know that there is
some reason for it."

The explorers forced the remaining vicugnas to turn back and follow
the trail in the direction from which they had come. When the last
animal had disappeared around the bend, Dr. Rander urged the mules
ahead, and they again took up the journey.

"I don't suppose the puma or whatever it was will frighten those
vicugnas back again, will it?" Joe was a bit worried as they labored
around the rough trail, which was even narrower than before.

"We'll hope not," the old man said.

"If the puma's there, maybe we can get a shot at it," suggested Bob.
"I'd like to bag one for Dad and the others."

But if there was one of these huge cats in the vicinity, it did not
make its presence known. Perhaps, as Joe mentioned, it had left for
another locality.

So closely did the youths look about that they did not notice the
wall of rock that appeared suddenly before them. Only Dr. Rander's
voice served to rouse them.

"Here we come to the first secret," he asserted, pointing to a small
opening in the wall of rock.

"So soon?" asked Bob wonderingly. "Why, I thought----"

"It is a tunnel," explained the old explorer. "One that was made by
the Incas. As far as I know, I am the only person who is aware of its
existence."

At once the boys were aflame with interest.

"And--and we must pass through it?" Bob peered at the narrow opening,
which seemed no different from many other crevices they had seen.

"Yes. There is no other way to reach the cave of gold. At least not
from this direction."

The adventurers got through the opening easily, but the mules
experienced more difficulty. And they did not at all like the idea of
plunging into a dark tunnel.

But finally they were forced through by Joe, who had gone back
outside. Then, with the aid of flashlights, the party proceeded to
thread their way in the narrow passage.

"How much of this is there?" asked Joe, when fully five minutes had
passed.

"At least a mile more," Dr. Rander returned. "It is very long."

But if it were a mile, it seemed to the youths like several times that
much, for in the damp, odorous tunnel the time passed very slowly.

"Will we ever reach the other side?" Joe was tiring.

At last the passageway became light, and then an opening loomed up and
let in the fresh air of the outside.

"Hurrah!" Joe was delighted. "But--where are we?"

On all sides of the travelers were towering peaks more lofty than any
they had yet seen. Some of the mountains were narrow and pointed, with
snow at their summit; others were merely huge rounded mounds of rock.
All were magnificent, inspiring thoughts of grandeur.

The youths and the old man were on a narrow shelf that was perhaps
five thousand feet above what looked like a tiny winding ribbon of
water. It passed in and out among the mountains, stretching far out of
sight in the distance.

"That is the Apurimac River," pointed out Dr. Rander, following the
boys' eyes. "It turns on northeast and finally comes near Mount
Panta----"

"That's where Dr. Rust and the other archæologists are," interrupted
Bob, and then added: "Wonder if they found any Inca ruins?"

"There are many that we know nothing about," the old explorer said.
"Peru and the Andes literally teem with fascinating ruins. Perhaps
there are more treasures, too."

Bob resolved to venture a bold question.

"How did you come to find this treasure cave?" he asked Dr. Rander.
"If you don't mind telling us."

"Not at all. It might interest you to know that I first found that
very tunnel that we just passed through." Dr. Rander pointed to the
entrance into the passageway, from which they had emerged. "I happened
to be camped not far away from that crevice in the mountainside that
we first saw. It seemed no different from other cracks, and at first I
thought nothing of it. But when I lingered about awhile I saw that
near the top the rocks were smoother than I usually found them. This
made me wonder if the opening were natural or man-made. My curiosity
got the better of me and prompted me to go through and see if I could
find anything unusual. Then I discovered the tunnel."

He paused, apparently finished.

"Then what? Is the cave near us now?" Joe was breathless with
interest.

"The treasure, you mean? No. It is many miles from here. Look,"--he
pointed around the mountainside--"see that winding trail? That is a
secret known only to us. It alone can take us to the place we're
after."

Joe sighed submissively.

"The old Andes are too much for me," he said. "I had no idea they were
as large and vast as this."

"You will see even more wonderful sights," Dr. Rander told him. "And
before we go many miles farther."

Indeed the boys found much to hold their interest. The awe-inspiring
cliffs, the stupendous rocky crags, the foamy river below, the
breath-taking heights--all these held a certain fascination for the
two youths. They found themselves absently bending their efforts too
much on seeing the sights and not enough on making out the dangerous
trail.

"Be careful here," Dr. Rander warned, as Joe almost slipped and fell.
"It surely would not do to roll down this steep slope."

"That would about put an end to everything for me," said Joe with a
grim smile.

The trail curved on up the mountainside until it reached a high
pointed crag, which had been visible for several miles. Then it
gradually circled around until it reached the base of the mountain.

"What's that noise?" demanded Bob Holton, stopping quickly to listen
to a deep rumbling sound that increased with every moment.

Dr. Rander looked up. Then his eyes opened wide with terror.

"It's an avalanche!" he cried hoarsely. "Tons of rocks are coming down
at us!"




CHAPTER XXII

The Deadly Snake


Over their shoulders the youths glanced up the mountainside and to
their horror saw that the old man was right.

Far up the slope was a great mass of stones and earth, rolling down in
a heavy cloud of dust. Every second saw the accumulation nearer and
larger. In but a brief time it would be upon the little group below.

"We must do something--without delay!" Dr. Rander's voice was cool and
resolute. "The mules--they must be pushed out of the way!"

Acting on the instant, Bob and Joe and the old man worked like madmen
to drive the pack animals over to a flat shelf that was but a few
hundred feet away. Even this did not offer absolute safety, for the
mass of rocks and earth might change its course and plunge down on the
shelf.

"We'll have to take a chance," Bob panted. "Most likely over here
we'll be out of the danger zone."

The flat stretch offered the only place of refuge. If the avalanche
should change its course, the adventurers and their pack animals would
surely be crushed.

There was a moment of fearful waiting, a brief period when the hearts
of all stood still, and the huge mass of rocks roared past and on down
the mountain slope.

"Thank goodness!" breathed Dr. Rander. "A narrow escape if there ever
was one."

Their eyes followed the plunging stone heap until, with a dull thud,
it struck the bottom of the abyss, far below.

"If that had struck us we'd have been smashed to pulp," muttered Joe
with a shudder.

"Think of something more pleasant," smiled Bob. "The treasure, for
instance."

That afternoon the three were struggling along the narrow path when
suddenly Bob caught sight of something up on a high shelf.

"Look," he said, pointing up to the flat stretch. "Inca ruins as sure
as I'm born."

"You are right," Dr. Rander assured him. "That building is an ancient
temple, where the Incas worshiped the sun god."

"Sounds interesting," Joe said eagerly. "Why can't we go up there and
explore the place?"

"Can if you want to," the old man replied. "I have been up, but I will
go again with you. Wait until I tie the mules."

It was a difficult climb to the shelf. All were gasping for breath
when they finally reached the ruins.

Those ruins the youths found interesting. The building was partially
intact, being constructed of huge stone blocks cemented together with
mud. It was shaped like a pyramid, the sides sloping up to form a
point at the top. The entire north end was in ruins, but the other
sections looked as if they had been built but recently.

"Let's go inside," suggested Bob, looking at the dark opening that
once no doubt was closed by a door.

The others agreed, and, led by Bob, entered the building. As the
windows were large and there was no covering over them, the
adventurers could easily see about.

They were in a large room, over which was an unusually high ceiling.
Several stone implements were scattered about; what they were doing in
a temple, the boys could not guess.

"Perhaps this was meant for a storehouse or some other kind of
building," thought Bob, but did not say so. He did not wish to
conflict with Dr. Rander's opinion.

But aside from these few stone objects, there was nothing in the
building that was of particular interest. Whether the structure had
been deserted by the Incas, or whether someone had robbed it of its
former contents, the youths did not know. Surely, if Dr. Rander was
right in his belief that he alone knew of this trail, no one had been
here.

They explored the building eagerly in search of anything else that
might have escaped their view before.

"Ouch!" cried Joe, slapping his leg. "What was that that bit me?"

"Oh, I should have told you," began the old man with a smile. "There
are fleas here."

"What th----" Joe was perplexed. "Fleas? What do they live on? There
isn't anything in these ruins----"

"That is out of my knowledge," Dr. Rander said. "I never have found
anything yet that they might eat. Unless it would be other fleas."

There was a general laugh.

"Whatever it is, it's enough to keep them alive," observed Bob,
scratching his arm. "At least as long as we stay they'll be able to
secure a good living."

"Suppose we get out and don't stay any longer," was the suggestion
made by Joe Lewis. "There isn't anything here----"

"What's that?" cried Bob suddenly, interrupting his friend.

Bob had heard a peculiar noise that caused him to turn about.

Again it came, a hideous hiss that made them jump in alarm.

"Snake!" pronounced Dr. Rander, and an instant later a long slim body
unwound itself and made slowly toward the three explorers.

"It's poisonous, all right," observed Bob, noting the peculiar shape of
the reptile's head.

"And we haven't a gun!" moaned Joe ruefully. "What will we do?"

"You mean we haven't a rifle, but we have a gun." Bob produced his
revolver, which he aimed carefully at the horrible staring eyes.

"I won't dare miss!" he thought, and then pulled the trigger.

The report of the pistol mingled with a sickening swishing noise as
the snake lashed about in its death struggle.

"You got him, all right." Joe felt a refreshing feeling of relief
creep over him.

Bob nodded.

"Let's get out of here," he said in a determined voice. "There's no
telling how many more of these creatures we may see if we don't."

"I should have brought the movie camera," laughed Joe, as they
descended the hill. "That would have made a peach of a picture."

"I'm glad you didn't," came from Dr. Rander. "Because the sight of
those ruins might have inspired some scientists to come over this
trail. And the secret treasure cave might be known to them--if they
could open the hidden door."

Dr. Rander, however, had not protested to the youths' taking movies of
the region they were passing through, even though there might be
danger of someone from the United States coming in search of other
ruins and treasure hideouts.

"I could not say anything against your doing that," he had told them.
"Especially since you were engaged by the motion-picture house."

So they had exposed film whenever they thought it advisable and were
well pleased with the results so far. All told, they had already
cranked off more than a thousand feet of film, and fully expected to
use that much more.

"These scenes ought to be interesting, too," remarked Bob, untying the
foremost mule. "I believe the Neuman Motion Picture Corporation will
be well satisfied with them."

"Let's hope so," Joe said. "The money we get from doing this is no
small sum."

The next day they plunged into a region that was wilder and more
dangerous to penetrate than any they had been in before. The rugged
Andes reached up on all sides of them, often forming narrow valleys
that were shut off from the rays of the sun.

"Sure is cold tonight," remarked Joe with a shiver.

They were camped beside a small spring that was fed by an underground
stream. Darkness had fallen, and with it had come the chill of the
Andean night.

Joe was resting peacefully beside the warm blaze of the campfire when
suddenly he caught sight of two small fiery lights coming slowly at
him.




CHAPTER XXIII

Descending Rapidly


Joe's first impulse was to get to his feet and utter an exclamation of
alarm. But he knew that this sudden movement might cause the creature,
whatever it was, to rush at him.

His rifle lay at his side for just such an emergency as this.
Thankfully Joe raised the gun, took aim, and fired between those two
lights, which had now taken the form of eyes.

Bang! The shot broke the stillness of the night and sent Bob and Dr.
Rander scurrying over to their friend. They had been on the opposite
side of the fire and had not noticed Joe's movements.

"What is it?" Bob was all excitement.

"Don't know," his friend replied. "Let's see."

The sound of the gun had not been followed by any other noise.
Evidently Joe's aim had been true, killing the creature instantly.

Bob produced a flashlight, which he turned in the direction in which
his friend had fired.

"Why--it's another snake!" exclaimed Dr. Rander. "A bola. It isn't
poisonous, but it is a good thing you got it. There is no way of
knowing what it might have been."

With the aid of the flashlight they examined the reptile closely. Its
head was almost shot off, making it useless as a specimen.

"I'd like to have it for Dad and the other naturalists," remarked Bob.
"But as it is, guess it's no good for anything."

"You should have been more careful in shooting it," teased Dr. Rander.
"Now if you had aimed at its body instead of its head----"

Joe smiled.

"A snake has eyes in only one place," he said laughingly, "and the
eyes are the only part of it you can see at night. Now if this fellow
had worn a badge to signify that he was a member of the Royal Order of
Andean Reptiles, maybe the fire shining on it would have given me a
good place to take aim at."

"Probably wouldn't bother with him anyway," said Bob. "After all,
we're out to find the treasure."

Nothing happened that night to disturb their slumber. They awoke the
next morning eager to continue the journey.

"Today we should come to the big secret," Dr. Rander told them during
breakfast. "If all goes well, we should get there this afternoon."

Bob was restless.

"Let's hurry and get going," he urged, untying the mules.

Farther over the rocky trail the three adventurers trudged, keeping a
sharp lookout for anything unusual.

Always in the distance were massive snow-clad peaks, which on this
morning were enshrouded in a heavy mist. Usually they were plainly
visible, especially through the high-powered binoculars that were
carried by Joe.

Gradually the path spiraled down the steep slope until it passed
through a narrow valley, which was green with a variety of luxuriant
vegetation. So dense were the plants that they almost formed a jungle.

"Look at this," cried Bob, moving over to a vine that was laden with
large red berries. "Wonder if they're good to eat?"

"Yes." The old man had broken off a branch and was eagerly partaking
of the fruit. "They are wild cherries, or tomatoes, as some call them.
There is nothing better for taste."

"Right you are!" agreed Joe, after he had eaten several of the
berries. "They're fine!"

They picked a sackful of the fruit to have at the noon meal. Then they
resumed the journey.

At places the trail was overgrown with weeds and grass, making it
difficult to follow it. But Dr. Rander had been through this region
before and did not hesitate long in picking out the right branch.

"I don't see how you can remember the way," Joe told him, when he had
pointed out one of three branches, each of which was almost parallel
to the others.

The old man laughed.

"I can't afford to forget," he said. "All that treasure is something
that is worth too much to be forgetting where it is. If it should
happen, though, that I should get turned around, I have a rough sketch
map of this region that I made at the very start."

On the other side of the valley was a steep slope that was entirely
devoid of vegetation. Look about as the youths did, they could see no
path. They were beginning to wonder when Dr. Rander broke the silence.

"From here there is no trail," he explained. "We'll have to cut our
way through the hard places and climb over large rocks. It won't be
easy, but we will be rewarded."

"No trail, huh?" thought Bob. "Here's where the fun begins."

It was far from fun, in the usual sense of the word. The three labored
over short, steep elevations, rocky precipices, narrow ridges, pulling
the sure-footed mules behind them. At last, when they finally reached
a high ledge, they sat down to get their breath.

"Whew!" gasped Joe, wiping the perspiration from his brow. "I don't
want much of that. Wonder how old Dr. Rander stands up under such a
strain?"

"Hardened to it, I suppose," was Bob's reply. "Since he left college
he's been nothing else but an explorer."

The old man had been at the back of the line, attending to the last
pack animal. There was a smile on his face as he approached his young
friends.

"We've made unusually good time," he said, sitting down beside them,
"and we can afford a rest."

"We earned it, all right," came from Joe. "How much more of this is
there?"

"A long stretch," Dr. Rander responded. "Several miles, to say the
least. Of course," he added, "it would not be long if we could go in a
straight line. But over mountains and around cliffs the going is much
different."

"I'll say it is!" Joe was still panting from the difficult climb. The
high altitude required an unusual amount of wind.

Fifteen minutes later they were ready to continue. The mules had been
coaxed ahead over the dangerous ledge.

"Getting darker," observed Bob Holton. "Wonder if it's going to rain?"

Dr. Rander looked up anxiously. Sure enough, heavy clouds were forming
above the mountain tops, hiding the sun from view.

"It would not be well for us to be caught in a storm here," the old
explorer said. "We must seek shelter somewhere. It certainly looks as
if a storm will be upon us before long."

They looked about for some place of refuge, such as a cave or
overhanging rock. But luck was not with them that day. They had
searched an hour under a sky that was rapidly becoming darker when
suddenly a terrific hailstorm struck them.

"Quick!" gasped Joe, who was almost frantic. "We must find some
place!"

"We're not finding it," returned his chum, who was taking the danger
more lightly. "And I guess there's nothing we can do but stay out here
in the open and endure it."

But a few minutes later Bob had become as serious as his friend. Hail
as large as marbles was falling with a terrible velocity, striking
the explorers' faces dangerously. One lump caught Joe squarely on the
nose, causing him to utter a cry of pain.

"This is awful!" he moaned, holding his hand in front of his eyes.

How long the storm would last they had not the faintest idea. Even Dr.
Rander could express no opinion.

Doggedly they fought off the hail, which bruised and cut their faces
and bodies. They wondered how the mules were standing it. Could the
animals endure the terrific onslaught? Or would they become
panic-stricken and plunge off the steep cliff?

After what seemed like hours, the hailstorm suddenly subsided and the
sky began to lighten. Ten minutes later the surrounding mountains bore
no evidence of the disturbance.

With the adventurers, however, it was a different matter. Their faces
were cut in many places, and their clothing was torn. A more
miserable-looking trio could hardly have been found.

"Get out the ointment," directed Bob. "We'll sure need plenty of it."

"The mules came through all right," observed Dr. Rander. "Cut and
bruised, but nothing more."

"It's funny," began Joe, looking up at the sun, which was now in full
view. "That was a very queer storm. It came quickly and ended the
same way."

"Hailstorms are rather common in this part," explained the old man,
getting out a box of antiseptics and first-aid remedies.

Their numerous wounds were treated with a soothing salve. Then, after
looking over the mules, they moved on around the mountainside.

At a huge notch in the rocky slope they stopped to examine a curious
formation that puzzled them. It was a long sloping slide, running
gradually down the mountainside. From all appearances it was as smooth
as glass.

"I don't know whether this is natural or man-made," said Dr. Rander.
"I never have been able to find out. But," he went on, "what concerns
us is that we'll have to slide down to the foot of the mountain."

"What!" Bob's surprise was beyond words. "Do you really mean that?"

"Every word of it," was the old man's reply. His little eyes twinkled.
"Don't you think much of the idea?"

Bob laughed.

"It was so sudden that I hadn't given it a thought," he answered.
"But"--gazing far down the smooth slope--"it looks rather inviting.
Will you go first?" The youth was not fully convinced that Dr. Rander
was in earnest.

"If I go, one of you will have to stay with the pack animals," the old
man said. "I don't think they had better try it," he added with a
laugh.

Bob and Joe looked puzzled.

"I don't understand," said the latter, hesitating. "Do you mean that
some of us will slide down this slope and some stay with the
mules--leave them here, I mean?"

"Oh, no," smiled Dr. Rander. "One of us will have to take the mules
down the trail. We could all go that way, but as it is very long, this
offers a short cut that you fellows can take. That is, if you want to.
When you get to the bottom you can wait until I get down the trail
with the pack animals."

"Where is the trail?" Bob secretly wondered if Dr. Rander had suddenly
changed his mind about sharing the treasure with them and was using
this means to evade them. He did not think the old man treacherous,
but he wanted to be on the safe side.

"Over there." Dr. Rander pointed to a narrow path that circled down
the mountainside.

"Suppose," Bob began, "you and Joe go down the slide while I take the
mules down the trail. I don't like the looks of that glassy slope."

"All right. I'm no longer young, but I still like sport. Here I go."

The next moment he was sliding rapidly down the polished incline.

When he was halfway down, Bob and Joe burst out in laughter. The sight
of the old man doing such a thing as this with so much enjoyment
aroused the youths' sense of humor.

"If he likes it so much, maybe I will," chuckled Joe, sitting down at
the edge.

"Good luck," called Bob, as his friend let go his hold and passed
swiftly down.

It was an unusual sensation to Joe, as he shot down the curving slide.
When younger he had often played on the slides in parks. But this was
something entirely different. To shoot down a tall mountain at a rapid
pace, on the straightaways and around curves, was indeed novel.

When over halfway down, the youth felt himself gradually lose
momentum, and he knew that the slide was flattening out. Too steep a
descent, especially near the bottom, would be dangerous.

At last he came to a stop beside Dr. Rander, who had been watching the
descent.

"How did you like it?" the old man asked.

"All right. Got rather warm, though. Wonder if it thinned my trousers
any? No, I guess not. Too smooth, I suppose."

Fifteen minutes later Bob came in sight leading the line of mules. He
laughed as he caught sight of them.

"Any worse for your experience?" the youth asked with a chuckle.

"Do we look it?" smiled Joe. "We enjoyed it."

As the sun was almost directly overhead they decided to remain at this
spot for the midday meal. All were extremely tired and hungry.

Bob prepared dinner, using water they had brought with them in
canteens. As a dessert they feasted on the delicious wild cherries
that they had picked that morning.

"Now let's get going," urged Joe, when the meal was over. "I'd like to
see that treasure."

Farther into the wilds they plunged, with not the faintest suggestion
of a trail to guide them.

"No trace of any vegetation here," observed Bob. "It's a good thing we
stopped where we did, or the mules probably wouldn't have had anything
to eat. There were a few stunted bushes and other plants back at the
foot of the slide."

An hour of climbing brought them to a place where a tall peak
obstructed their view.

They trudged around and then suddenly found themselves at the bank of
the roaring Apurimac River.

"On a little farther," Dr. Rander said, urging the mules to ascend the
difficult slope.

At last they came to a place where a high rock protruded far over the
river. Here the old explorer called a halt and pointed up the side of
a mountain.

"In that little notch up there is the entrance to the treasure," he
said. "As I said before, there is a huge cave that occupies the entire
mountain. There we will find the treasure, if there is any."

The youths' hearts beat rapidly. They could hardly believe that at
last they were nearing the great secret.

"But," hesitated Bob Holton, "how are we going to get across this
roaring river?"

"That," the old explorer returned, "will be the most difficult part of
our entire journey. Come. Let me show you."

They followed him to the edge of a high rock that protruded far out
over the seething rapids.

"Look there," he said, pointing to something.

Stretching from the rock across the river to another protruding crag
was a heavy metal wire, which, strange to say, showed not the
slightest trace of rust.

"That cable was put there by the Incas," Dr. Rander said. "It is
hundreds of years old, but still looks as if it had been built but
yesterday. It is coated with some secret preservative, which prevents
it from rusting through."

"Interesting," remarked Joe. "But what about it?"

The old man replied at once.

"We must cross the river by hanging from the cable with our hands," he
said quietly.

Joe's heart sank. Secretly he felt that if he were to undertake the
dangerous venture he would meet with tragedy.




CHAPTER XXIV

The Big Secret


"Careful, now."

Dr. Rander was slowly and dangerously hanging from the heavy wire with
his hands, working his way steadily across the roaring rapids below.
If he were to fall, it would probably seal his doom, even though the
youths held one end of a stout rope that was tied securely around his
waist.

"Think he'll make it?" Bob looked on anxiously, half expecting to see
the old man let go and plunge into the seething water below.

Slowly but surely he swung across, holding on with a grip of steel. It
seemed remarkable that a person of his age could withstand the arduous
tasks connected with exploration. But no doubt he was hardened to an
eventful outdoor life of adventure.

"He's over," cried Joe happily. "Made it all right. Didn't even
threaten to let go. Now I wonder if we can do as well?"

The youths had yet to see.

Joe was next to swing across. He walked over to the cable and gazed
doubtfully first at the boiling stream below, then at Dr. Rander on
the opposite cliff.

"Go ahead," said Bob. "Might as well get it over."

"Yeah. But I wish it weren't necessary to do this. I suppose, though,
that I can do it if Dr. Rander can."

Joe sat down on the edge of the cliff, took hold of the heavy wire,
and slowly let himself down.

For a brief moment it seemed as if his arms would be torn from their
sockets, for, although he was not heavy, the strain was very great.

"I've got to make it!" he told himself, gritting his teeth. He refused
to think of what might happen if he were to plunge into the roaring
rapids below.

"Don't let go, whatever you do!" Bob, on the rock, was holding the
rope tightly, ready to pull his friend to safety if the latter should
be forced to release his grip.

Joe swung across with a certain determination that was luckily with
him in every emergency. He did not look below for fear of becoming
frightened.

At last, when he felt that he could stand no more of this torture,
the youth felt his foot touch rock, and he knew that he was safe.

"Hurrah!" cried Bob Holton, waving his arms in the air. "Now here I
come."

Bob would find the feat more difficult, since he was heavier than
either of the two who had crossed. But usually when he set his mind on
doing a thing he was able to do it.

But first he walked over to the mules, which had been tethered
securely by Dr. Rander, and got out a stronger rope, which he tied
around his waist and shoulders. A small weight he fixed at the other
end, and then moved back to the edge of the rock.

"Here. Catch this," he called, and threw the rope over to Joe on the
other side of the river.

When everything was in readiness he slowly lowered himself until he
could grasp the wire that stretched across the stream. Then, setting
his nerves for the trying task, he let his feet drop.

For one awful minute Bob's heart stood still. Then he got a grip on
himself and swung easily across to the other side.

"That was fine!" praised Dr. Rander. "You never flinched. Now let's
hurry up the mountain to the treasure."

"Do you suppose the mules will be safe over there?" queried Joe
anxiously. "We couldn't take any food with us across the river. If
anything should happen to them----"

"There is no danger," the old man assured him. "Probably no one has
been in this section for years and years."

Notwithstanding this, the young men were still worried. They realized
that they would be in a grave predicament if anything should befall
the provisions.

This anxiety gradually wore off, however, as they neared the treasure
cave.

"Hard climb, but nothing will stop us now," smiled Joe happily.

"You will be amazed when you look upon the wonders in the cave," Dr.
Rander told them. "It will exceed your wildest dream."

"How did they all get there?" inquired Bob.

"I do not know. They were placed there by some wealthy Inca--perhaps a
king--for safe keeping. It might have been that this was at the time
of the Spanish invasion, and that the owner was later killed by the
conquering troops. At any rate, the secret remained as such until I
accidentally found it."

"You sure were lucky," remarked Joe. "Perhaps it wouldn't have been
discovered at all if you hadn't located it."

At a point near the ledge, the mountain grew so steep as to make
climbing a very arduous task. A single misstep would have meant a
horrible plunge into the roaring rapids below.

At last they came to the top of the ledge, before the notch cut in the
mountainside.

"See that dark entrance?" asked Dr. Rander. "That is a tunnel that
leads to the cavern. Come."

The youths followed the old man into the opening, which was made light
by the latter's flashlight. The passage seemed to lead steadily
upward, probably into the peak of the mountain.

"Do you suppose this tunnel was constructed?" asked Joe, after five
minutes had passed.

"I believe so," Dr. Rander returned. "When we get farther on, you will
think so too."

Fifteen minutes of walking brought them to the end of the tunnel. From
all appearances there was nothing but natural rock before them.

"Watch," said Dr. Rander, moving over to the end of the cave.

He reached up and pressed a mysterious button. Then he stepped back
and waited.

Suddenly the youths gasped in awe, as they saw the huge stone wall
slowly swing inward. As it made an opening, a beam of natural light
flashed into the cave, making the use of a flashlight no longer
necessary.

"Huh! That's funny!" muttered Joe. "Must be an entrance to the outside
somewhere."

"If you can find it, it is more than I can do," laughed Dr. Rander.

The opening grew larger, and the light brighter. When the ponderous
stone wall had swung away to the utmost, Bob and Joe followed the old
man through the entrance.

As they did so their eyes opened wide and their jaws dropped at the
sight that lay before them. Ahead was a great stone room, fully fifty
feet square, in which were scores of objects carved from stone.
Statues of men, birds, llamas, pumas, and many other animals were all
about. Ears of corn, plows, chairs, pottery--all these and many more
objects were carved out of stone.

It was a wonderful collection, one that would delight the eye of any
archæologist. Bob and Joe inspected the various objects with interest,
knowing that Dr. Rust and his fellow scientists would give a great
deal to know of the existence of this place of wonder.

"All this is very interesting," remarked the old man. "But what we
really came after was treasure--if there is any."

"Yeah. Where is the place where you said it might be?" Bob was anxious
to look for something still more valuable than the stone objects.

"I will show you."

Dr. Rander stepped over to one corner of the large room, where was a
huge statue of a man, perhaps an Inca king.

"Now look closely," he said, when the youths had followed him.

The old man walked up to the statue and stood directly in front of it.
Then he waited.

At that moment something happened that caused Bob and Joe to gasp in
wonder. Slowly, surely, the statue sank into the floor until it
disappeared from sight. Directly below the resulting opening was a
ladder, which led down into another gigantic room.

"Well, of all things!" cried Joe in utter amazement. "That sure is a
secret if there ever was one."

"Let us go down." Dr. Rander was making his way down the ladder,
motioning for the youths to follow.

They did and soon found themselves in a huge cavern cut out of solid
rock. Here were more stone objects similar to the ones in the room
above them.

"This way," pointed out the old man, walking over to one side of the
cave.

"Wonder where the light comes from?" pondered Bob. "It's from the
outside, all right, but how does it get in?"

Dr. Rander bent over and pressed something in a crack in the floor,
straightening up a moment later.

Again the youths were filled with amazement. A huge stone block swung
away on unseen hinges, leaving an opening perhaps four feet in width.

"Now we must use flashlights," Dr. Rander said, stepping inside.
"There is no opening to the outside, apparently."

The beams of the electric torches revealed the fact that they were in
another cave.

"Over here," explained the old man, "is a sort of bin cut out of the
rock. It is covered with a stone that I cannot lift. But I feel sure
that all three of us can."

"Let's have a look at it," said Bob.

Together they heaved on the stone block with all their strength.
Before long they saw that their efforts were not in vain. The stone
was slowly slipping from the top of the bin. At length it fell to the
floor with a dull thud.

The explorers turned the beams of the flashlights into the opening,
looking about eagerly.

"Here's something," announced Joe, bringing out a small iron box.

"Open it," directed Dr. Rander.

Joe did--and then cried out in wonder as he saw its contents.




CHAPTER XXV

Another Hidden Wonder


"Gold!" cried Joe happily. "Gold beads, as sure as I'm alive!"

"And scores of them, too," observed Bob. "Bet they're worth hundreds
and hundreds of dollars."

They examined the little objects with interest, joyful that at last
their efforts had been rewarded. The beads still shone brightly,
although they had been in the cavern for hundreds of years. That they
were really gold, no one doubted in the slightest.

"Who put them here?" asked Bob Holton, when they were ready to leave
for the outside, the jewel box in their possession.

"The Incas," returned Dr. Rander. "Perhaps it was an Inca king. At any
rate it was someone who was wealthy."

They looked about for any other treasure that might be in the room,
but found none. At last they left the cave, closing the stone door
behind them.

Led by Dr. Rander, they climbed the ladder, and then passed through
the great room that was filled with the stone statues.

"We must hurry before it gets dark," said Dr. Rander, closing the
secret stone wall by pressing the hidden button. "It will not do to
cross that river at night."

"Bad enough in the daytime," added Joe, as they made their way through
the dark tunnel.

When at last they reached the outside they saw that they had but a few
minutes before the sun would sink from sight.

Down the steep slope they climbed until at last they reached the cliff
which protruded over the roaring river.

"How are we going to get the jewel box across?" asked Joe. "It isn't
large, but it's too big to put in our pockets."

"Use a rope, I suppose," was the answer from Bob. "We'll tie it
tightly across somebody's back."

This suggestion was followed, and before long the three were on the
other side of the rapids. They were relieved to find that the mules
were resting peacefully.

"I don't like the idea of crossing that river any more," said Bob with
a frown. "But I would like to go over to the secret cavern again
tomorrow."

"What for?" demanded Joe.

"I have two good reasons," his friend answered. "First, I would like
to take some movies of the place. And the other one is that I'd
like to make a detailed map to give to Dr. Rust and the other
archæologists. They'll appreciate it, all right. Be tickled to death
to know that we found all those Inca remains."

The next morning they did as Bob wished and once more swung themselves
across the boiling rapids, coming to the opposite side safely.

Motion pictures of the secret cavern and its contents were taken, and
then a reliable map was made of the region, including the exact
location of the mysterious buttons that moved the large stone doors.

Although Bob was assisted by his friends, he did not have everything
completed until noon.

With one last look at the mountain of secrets, the three turned and
retraced their footsteps to the river.

"Last time across," said Joe with a sigh of relief. From the start he
had feared the dangerous swing from the cable.

No harm befell them, however, and they reached the other side ready to
start the journey to Pasaje, where Karl Sutman would be waiting with
his airplane.

"Good old Karl," said Bob affectionately. "It will be fine to see him
again. And Dad and the others. I hope they're all right."

"With you on that," came from Joe quickly.

"It will take us many days to get to Pasaje," Dr. Rander put in. He
intended to go with the youths to that town, where he wished to remain
for several days.

"Wonder if we'll see anything more of interest?" Joe was anxious to
observe all that was worthwhile.

"There are other secrets I will show you," explained Dr. Rander. "But
as far as I know there is no more treasure."

They decided to rest the remainder of that day, for all were tired
from the strain. On a little shelf beside the roaring Apurimac they
made camp.

"Now lead us to more secrets," said Bob the next morning, when they
were ready to resume the journey.

"I will," returned the old man.

He kept his promise. Late that afternoon they had been following a
narrow trail that curved with the river when Dr. Rander stopped and
pointed up to a tall peak.

"Beyond that is a little hidden valley," he told the youths. "In it is
a tall tower that was built by the Incas. As far as I know, I am the
only person who has ever found it."

"Sounds interesting," said Joe. "Can we go there?"

"Yes. Follow me."

He tied the mules securely and then began the dangerous ascent of the
high peak, Bob and Joe at his heels.

After a half-hour of struggling they reached the summit, which was
covered with a thin coating of snow.

"Now, look down," the old man said.

Far, far below, on the other side of the mountain, was a narrow valley
that was green with tropical vegetation. It appeared much lower than
might be expected.

"Look away over to your right," directed Dr. Rander. "See that tall
tower?"

"Why--why, yes!" Bob was struck with wonder. "Let's go down and see
it. Have you ever been there?" he asked the old man.

"Not close," was the reply. "I have only looked at it from a distance.
Lack of time prevented me from going over there."

"We haven't a great deal of time," said Joe. "But I wouldn't miss
taking that in for hardly anything."

He led the way down the steep slope, which required not a little
caution. A single misstep would have meant a terrible fall to the
bottom of the cañon.

An hour of careful climbing and their feet touched the green grass
below. The tower, they observed, was several hundred yards in the
distance.

"Probably we will find other ruins near," remarked Joe Lewis, as they
walked toward the corner of the narrow valley.

"Where there is one there is likely to be two," smiled Dr. Rander.
"And maybe you're right."

When they came nearer they saw that the tower was at least a hundred
feet high. It was built of small blocks of stone, carefully fitted
together. Near the base was a heavy growth of vines and creepers,
which wound around the tower up to a height of twenty feet.

"Here's a door," called Bob, who had gone around the other side.
"Let's go in and see what we can find."

With the aid of small flashlights they entered the structure and
looked about.

Everywhere were cobwebs and other evidences of age, showing that it
had not been occupied for hundreds of years. In one corner was a
narrow winding stairway, which evidently led to the top.

"Shall we go up?" asked Joe.

"Sure. Why not?" Bob was already halfway up the first flight.

The others followed him, winding slowly up the narrow stairs. They
wondered a little if it might be safe to venture up into this
time-worn structure.

After what seemed like hours, they left the last flight of stairs and
turned to go out on the top floor.

As they did so, they saw something that was horrible and disgusting.




CHAPTER XXVI

A Narrow Escape


Lying about on the stone floor were at least ten human skeletons,
which were white with age. They were in no fixed positions, but were
scattered aimlessly over the dusty floor.

Bob was the first to break the silence.

"Wonder how they got here?" he asked.

"Perhaps they are the remains of soldiers who guarded this tower," was
the opinion of Dr. Rander. "Here," he went on, "look at this. It's a
dagger--made of stone."

"You might be right," commented Joe. "But then, it's possible that the
dagger belonged to someone who came up and murdered those who were
here."

The explorers examined the skeletons for several minutes before going
to the edge and looking down on the surrounding valley.

"Can see quite a distance," observed Bob, peering out at a distant
mountain.

"Yes," agreed Joe. "There----"

At that moment he was interrupted by a cracking noise, which seemed to
come from the tower.

"What's that?" cried Dr. Rander excitedly.

But when it was repeated, there was no doubt in their minds as to the
origin of the strange noise.

"It's the tower!" exclaimed Bob fearfully. "I hope I'm wrong, but I'm
afraid it's going to fall. Hurry! Let's get down to the ground."

The three lost no time in scrambling down the stairs. They reached the
bottom in safety, and then dashed outside, Dr. Rander displaying
remarkable agility for his age.

Then something happened that filled them with terror. With one last
creak, the old tower leaned slowly to the south, poised for a brief
moment, and went crumbling to the ground. There was a report like that
of a cannon, followed by a heavy cloud of dust and small particles of
rock.

The explorers' hearts were beating like trip hammers; their faces were
red with excitement.

"Thank God that we escaped in time!" breathed Dr. Rander. "A few
seconds more and we would have been caught beneath tons of rock!"

"And what a death!" muttered Joe with a shudder. "I don't want to even
think of it."

They sat down on the ground to relieve themselves of the terrible
strain. Especially did the old man show signs of exertion. At first
the youths half expected to see him fall with heart failure, for he
was terribly exhausted.

The rest, however, did him good, and before long he was apparently no
worse for the horrible experience.

"Funny that tower should collapse just at this time, isn't it?" said
Bob. "I suppose, though, that it was ready to go at any time, and our
weight proved too much for it."

"That probably explains what happened," came from the old man. "If no
one had found it, perhaps it would have remained intact for many years
yet."

They put in no more time here, but turned and went back to the peak.

Very difficult it was to scale the steep slope, but at last they
reached the top and descended to the other side.

"The mules are all right," observed Bob. "Suppose we get going without
delay. I'd like to get to Pasaje as soon as possible. I'm getting
anxious to see Dad and the others of the expedition."

"It will still take time," Dr. Rander told him. "There are many miles
of difficult travel before us."

And difficult it was. Although the adventurers had previously found it
hard to make progress through the rugged mountains, they now
experienced even more hindrances.

Unfortunately, Dr. Rander was not overly familiar with this section
and often made mistakes in pointing out the best course of travel.

It was not uncommon for the adventurers to come upon heavy forests at
elevations of fifteen thousand feet. This surprised Bob and Joe, who
did not expect to see trees growing at such high altitudes.

"There really is no such thing as the 'tree line' in the Andes,"
explained the old explorer. "In fact, it is possible to find forests
at unusually high altitudes."

As they trudged on they came to more wild-cherry plants, the fruit of
which they ate hungrily. It was refreshing to have fresh fruit after
eating nothing but dried goods.

As much as possible they followed the banks of the Apurimac River, for
Pasaje, their destination, is situated just above the point where the
stream branches.

As they went farther, the mountains became more lofty, and snow on the
summits was more common. They never climbed high enough, however, to
come in contact with it.

Suddenly, upon hearing an unusual noise, Joe glanced around, and then
gasped in apprehension.

"One of the mules is stuck in mud!" he cried. "Quick! We must do
something at once!"

Without delay the old man turned about, walked back to one of the pack
animals, and secured a long heavy rope. Then he moved on to the rear
of the line, where one of the mules was struggling to free itself from
the black bog.

"Bob, you had better come to the rescue," he said, after a moment of
pondering. "You're pretty good at lassoing, as you showed us several
days ago on that narrow ledge. Won't you try it and see what you can
do?"

"Where will I throw the rope, over the mule's head?"

"Yes. Tighten it around the animal's neck."

"But--won't it choke?"

"Not for a few minutes. There is no other way to pull the mule out. If
we go too close we'll get caught ourselves."

"All right, then. Here goes."

Bob took the rope, made a loop, and stepped as near as he thought
possible with safety.

"If I miss my aim, I can't help it," the youth said, as he threw the
lasso.

Joe cried out happily as he saw that the loop went directly over the
mule's head. Dr. Rander's face also lightened.

All three pulled on the rope with all their strength, but their
efforts appeared to be in vain. The treacherous bog had engulfed its
helpless victim too tightly.

"We've got to get that animal out!" cried Joe, redoubling his efforts.
"There's a lot of valuable supplies on its back."

But how? They were doing all they knew of. If that were not
sufficient, the mule would have to go down.

"We're losing steadily," observed Bob grimly. "But I guess we can't
help it."

Despite their furious efforts to draw the beast to safety, it was
sinking rapidly. Already its body was nearly under. In but a brief
time its head, too, would be engulfed.

But the adventurers kept up doggedly, determined to win the battle
even though defeat was staring them in the face.

With one last effort, they gave the rope a new stronger pull. But it
was not enough. The weight of the mule and its burden was too much,
and the animal's head slid horribly into the oozing mud, to disappear
forever.

Bob slumped down on the grass.

"We lost," he murmured gravely. "Now we're one pack animal short."

"And there were quite a few valuable objects in the pack, too," added
Joe, "not to say anything about losing the animal."

"Have to get along some way," Dr. Rander said. "There is no use in
thinking anything more about it."

"Wonder what the mule thought about when he went under?" mused Joe.
"It must have been terrible."

They resolved to follow the old man's suggestion and forget the loss
as best they could. After all, it was lucky that one of them had not
been the victim.

Again they took up the journey, this time keeping a closer lookout for
other bogs. But Dr. Rander did not know this region any too well, and
could not guide them as surely as he would have liked to.

In the fascinating mountains the time passed rapidly. It was two days
after they had lost the mule when Dr. Rander pointed to something in
the distant sky.

"That's a condor," he said, his eyes trying to make out the flying
form more clearly.

"It is at that," affirmed Bob, looking through his binoculars. "And
what's more, it's white. A _condor real_, as sure as I'm standing
here!"

"Let's see," said Joe, and took the glasses his friend handed him.

A few moments of observing and he nodded, giving the binoculars to the
old man.

"You're right," Joe said to his chum. "And oh! Wouldn't our dads and
Mr. Wallace like to be here now! A white condor! One of the creatures
they wanted most."

"Maybe we can get it for them," muttered Bob, grasping a shotgun. "Do
you suppose there's a chance?"

"Not unless it flies nearer," returned Dr. Rander. "Even then the bird
would probably fall to the bottom of the cañon, and that would mean a
dangerous descent."

"I'm going to see, anyway," Bob persisted, following the soaring form
through his powerful binoculars.

"Look what I've found," called Joe, who had climbed down to a narrow
ledge several yards below the others.

"Why--it's a nest," exclaimed Bob, upon descending to the shelf. "And
look at those eggs. Sure are whoppers. Say," he cried suddenly, "I bet
I know everything now. This belongs to that white condor. Look.
There's a white feather. See it?"

"You're probably right," said Dr. Rander, moving down to the ledge.
"Let us look about more. We may find something else of interest."

But all searching was stopped a second later when Joe happened to
glance up.

"The condor!" he cried fearfully. "It's coming at us!"




CHAPTER XXVII

Fighting Desperately


There was not a moment to lose. With the huge white condor swooping
down upon them, the explorers knew that they must act quickly.
Unfortunately their rifles had been left on the trail above. Before
they could secure the weapons the huge bird would be upon them and
would probably use its terrible claws and beak to great advantage.

"My knife is all we have to defend ourselves with," said Joe, watching
the large form advance toward them. "But I'm going to use it."

The condor came on swiftly. It circled around a few times near its
nest and then rushed madly at the little group of adventurers.

Now it was barely ten feet away and coming with deadly aim. In but a
brief moment it would be in a position where it could work deadly
havoc with its sharp claws.

Joe had his long hunting knife in readiness now, waiting for an
opportune moment. Then it came.

The huge white bird was soaring directly above its human enemies. As
it dropped lower, Joe lunged forward and plunged the sharp knife
through one of the long, thin legs.

Uttering a curious sound, the condor darted away, circled around for a
brief period, and then flew at the explorers with a new determination.

One of the horrible claws shot out and caught Joe's arm, the impact
knocking the knife from the youth's hand. It went hurtling to the
bottom of the abyss, far below.

Joe was weaponless, helpless!

New horror crept over him when he suddenly felt himself leaving the
ground. Not fifteen feet away was the edge of the cliff! Vainly he
tried to escape from the clutch of that formidable claw.

Meanwhile, Bob and the old man were not inactive. They knew that it
would only be a short time before their friend would be carried over
the brink of the cliff. And that must be prevented at any cost.

Looking wildly about, Bob caught sight of a rock about half as large
as a brick. Almost frantic, he picked it up, and with desperate
strength he sent it crashing into the condor's body.

The force was terrific, and for a moment it seemed as if the condor
were going to drop. But it righted itself and carried the helpless
Joe still farther toward the rocky edge.

"I'm going to try something," blurted out Bob, his face red with an
awful fear. "You run up to the mules and get a rifle--quick!" he said
to Dr. Rander.

As a last resort, Bob hurled his hundred and eighty pounds at Joe's
feet, and caught hold with a grip of steel. He wondered if the huge
bird could lift both himself and his friend. If it could....

At that moment Dr. Rander scrambled down the rocky slope with a rifle,
which he aimed unflinchingly at the condor's body. The next moment the
gun barked.

With a terrific fluttering of its heavy wings, the bird sank slowly to
the ground. It touched the hard soil, and then with a convulsive
twitch it lay still.

For almost a minute there was silence among the little party of
adventurers. They were panting furiously, and their wide eyes had not
yet lost their look of terror. Perspiration was streaming from them,
making their faces shine gruesomely. It had been one of the narrowest
escapes they had had so far.

Finally Joe wiped his face and looked at Bob with intense gratitude.
Then his eyes fell on Dr. Rander, whose rifle was still warm from the
timely shot.

"I don't know how to thank you," he said warmly. "If you hadn't been
so plucky, I would probably be lying in a broken mass at the bottom of
the gorge right now. It was simply wonderful!"

"Forget it!" Bob disclaimed any praise offered him. "The only thing
now that matters is that you're alive."

"Thank Bob for that," the old man said. "If he had not thrown himself
at your feet you would surely have gone over the cliff."

"But it was your shot that finished the job," protested Bob Holton.
"Even with the weight of both of us the condor was slowly dragging us
toward the brink."

"I'm afraid my bullet would have been too late if you hadn't done what
you did," persisted the old man.

"All right. Have it your own way." With a laugh Bob dropped the matter
and stooped over to examine the huge white bird.

It must have had a wing spread of over ten feet. Later measurements
showed that this was accurate. But what impressed the youths most was
its pure white feathers, which looked as clean as if they had been
recently washed. The terrible claws and long sharp beak next caught
the youths' eyes, and their respect for the power of this monstrous
bird was increased.

"Quite a specimen," observed Joe. "And speaking of specimens," he went
on, "why can't we skin it and take it with us? Our dads and Mr.
Wallace would sure be tickled. The white condor! Boy! I can just see
them giving cries of delight."

"Nothing to prevent us," returned the other youth. "We may find it
hard to place in our mule train, but we'll manage some way."

Bob secured a long knife, and with a skill that he learned while on
other hunting trips he cut the bird's skin open down the breast. A few
minutes more and the task was completed.

Without the weight of the body, the skin was light, and they had no
difficulty in tying it over the back of one of the mules, which
appeared not to notice the extra load.

With one last look at the spot where Joe had almost met his death,
they turned and drove the pack animals ahead on the remainder of the
journey to Pasaje.

But now they were more anxious than ever to reach their destination
and fly with Karl Sutman to the place where their fathers were
hunting. With every minute they longed still more to reach the town
they were approaching.

"I hope nothing further comes up to stay us," remarked Bob, as they
descended a steep slope. "Somehow I've had enough excitement for a
while."

"So have I," said Joe. "But of course there's no way of telling what
we may meet in these mountains."

The next day they found themselves in a wide valley, which was covered
with a heavy growth of dense vegetation. Tree ferns were quite
prominent, growing in large clusters that dotted the valley. Bright
flowers were also numerous, some of them unusual in shape and form.

And with this heavy vegetation came several varieties of wild animals,
among them being foxes, lizards, guinea pigs, and a host of birds. The
youths could easily have shot some, but they did not wish to lose time
in doing so.

"I believe we are getting close to Pasaje now," announced the old man,
as he led the way around the winding Apurimac River.

Notwithstanding this, they traveled all that day without coming to the
town. Camp was made at a clearing near the stream, supper was
prepared, and then all retired, knowing that the following day would
witness their coming to their destination.

Early the next morning the young men saw something that thrilled them
with delight. They had been breaking camp and were almost ready to
resume the tramp when suddenly their keen ears caught the sound of a
motor. Looking up, they plainly made out an airplane in the sky above
them.

"That's Karl!" cried Joe joyously. "I wouldn't be afraid to bet
anything that it is."

"I sure hope you're right," came from Bob. "Gee! Won't it be swell to
see him again?"

"Of course there's a chance that he won't see us," said the other boy.
"But I believe he will. He'll be looking around for us closely. Maybe
that's why he's here now."

Bob started, as an ominous thought struck him.

"Do you suppose anything's happened--to our dads, I mean?" he asked in
a tense voice.

Joe's face darkened.

"I--I hadn't thought of that," he replied solemnly.

They watched the airplane closely, expecting at every moment to see it
head downward.

Then it came.

"Hurrah!" Bob was overjoyed. "Karl sees us, all right. And it's Karl,
too," he observed, as the monoplane came closer.

As the machine flew closer it circled around the little group below,
rapidly flying lower. When within a hundred feet of them, its cabin
window opened, and Karl's face was thrust out.

"Hello, up there!" shouted Bob, and received an answering greeting.
But the noise of the 'plane's engine made it impossible for the
adventurers to understand the aviator's words.

While the three were still gazing up at the huge monoplane they saw
something that caused them to look all the closer. They made out
Karl's arm reaching out of the cockpit. Then they saw something white
drop toward the ground.

"It's a small parachute," observed Joe, his heart beating rapidly.
"Wonder what's tied to it?"

As there was no wind, the object fell in a straight line, the
parachute opened and began to float slowly above the onlookers. Before
long it came to the ground within fifteen feet of them. Karl had
certainly aimed accurately.

"Hurry!" cried Joe. "Let's see what it is. Maybe something's happened
to our dads or the others."

He picked up the parachute, at the end of which was attached a small
box. Opening it, the youth found a folded paper.

"Quick!" murmured Bob. "Let's see what he has to say."




CHAPTER XXVIII

Almost a Tragedy


Rather nervously Joe unfolded the paper, hastily read it, and then
gave a sigh of relief.

"Nothing wrong," he told his friends. "Take a look."

"H'm," observed Bob. "He only says he's going to land in a level field
about a mile from here, and that he'd better take us up with him from
there, instead of waiting till we get to Pasaje. No other place near
to land on. Closes by saying everything is all right."

"So he wants us to go up with him now," mused Joe. "Doesn't want to
wait till we get to Pasaje. I hate to do that. I don't like to leave
Dr. Rander till we get to the town. It doesn't seem right to come with
him all this distance and then go off and leave him here in the
mountains."

"Don't worry about me," said the old explorer quickly. "I have been
through these mountains alone many times. I can manage the mules all
right. And the town can't be far away."

"We'd go with you anyway," Bob told him, "only Karl says there isn't
another landing place near."

Without loss of time the three continued toward the level spot on
which the aviator had landed, at length coming in sight of the
monoplane.

Karl rushed out to meet them, his face bright at finding that all were
alive and well.

"You old rascal!" cried Joe, shaking the young man's hand warmly.

"How'd you know we were here?" asked Bob, who was also very glad to
see the aviator.

"I saw you," Karl Sutman explained. "I thought I'd take a short flight
over this section to see if I could locate you."

"You did, all right." Joe was delighted. "Found us away out here in
the wilds." He hesitated a moment and glanced at Dr. Rander. But the
latter had already been introduced to Karl Sutman, and needed no
introduction by the youths.

There was one question in the aviator's mind that he could wait no
longer to ask.

"The treasure you were searching for--did you find any?" he inquired.
"And the Inca secrets, too. How about them?"

Bob smiled happily.

"We did," he answered. "Found both the treasure and the secrets."

When shown the little box of gold trinkets, Karl gasped in
astonishment.

"Is that all you found?" he demanded. "I thought there might have been
some gold statues, or the like."

"If there were we couldn't locate them," Joe said. "We considered
ourselves lucky in finding what we did. They are worth many hundreds
of dollars, maybe thousands."

"Dad and Mr. Lewis and the others--are they all right?" Bob was
anxious to learn if any misfortune had befallen his father and
friends.

"They're still hunting for specimens," returned the aviator. "Mr.
Wallace fell down a mountain and hurt himself slightly, but he's about
all right now. And you should see the large collection of birds and
animals they have."

"We have something that may interest them," declared Joe, and showed
Karl the huge condor, at the same time telling about his narrow escape
from death.

"Wow!" Karl exclaimed when the youth had finished. "And Bob and Doc
Rander came to your rescue, did they? Good for them."

It was later decided that Bob and Joe accompany Karl at once in the
monoplane to the Comberciato River, where the chums' fathers were
collecting specimens. The old man explained that he did not mind going
on alone to Pasaje, where he had business.

"But before you leave," Dr. Rander began, "I want to divide the
treasure with you fellows," addressing Bob and Joe.

"Don't give us half," Joe said pleadingly. "After all, it was your
efforts that located the secret mountain cavern."

The old man held up a hand for silence.

"You forget that I owe my life to you," he reminded them. "If it had
not been for your coming to my rescue, I would not be here to enjoy
the treasure."

"But----" began Joe.

"Say no more," Dr. Rander silenced him. "Half of the gold is yours."

He spent the next half-hour in dividing the treasure, giving the boys
a good share. They thanked him warmly, then turned to Karl Sutman.

"Can we get started before long?" asked Joe. "I'm anxious to see
everybody."

"Sure." The aviator was willing. "Let's get your stuff loaded in the
'plane."

They worked steadily until noon, at which time everything that
belonged to the youths was packed in the supply compartment of the
monoplane.

After the meal they bade Dr. Rander an affectionate farewell and
stepped into the cabin. Karl started the engine, and then, with a roar
and a rush, they started rolling over the field.

The old man waved as they left the ground and headed toward the north.
The last the air travelers saw of him he was getting the pack animals
ready to finish the journey to Pasaje.

"I suppose we've seen the last of him," remarked Bob, as they left the
ground. "We may hear from him later, though. He has our addresses."

"Rather an odd character, isn't he?" said Joe. "Seems strange that
he'd want to remain in these mountains all his life."

During the next few hours Karl sent the airplane ahead over mountains
that were more rugged than any the youths had ever seen before. He was
steering the machine near Mount Panta and the locality in which were
Dr. Rust and the other archæologists when suddenly he found himself
almost unconsciously entering a heavy cloud.

A second later, when he realized what he had done, the aviator saw
that it was too late. Already the 'plane was in the midst of a heavy
opaque atmosphere of white.

"I was a nut for getting in a place like this," Karl said through the
telephone. "And there's no way of getting out now only to go on
through it."

Karl well knew that they were in grave danger of crashing into the
side of some lofty peak. They were in a region of tall mountains, and
some high summit might easily loom up before them.

For the next few minutes the youths' hearts were in their mouths. They
knew that Karl was an excellent pilot, but they also knew that he
could do nothing if sudden tragedy might come upon them.

"What's that?" cried Bob quickly. He had seen something that looked
like a huge black mass directly before them.

Joe sat on the edge of his seat, expecting every moment to feel a
terrible crash and then.... For the first time he wondered what death
was like.

Cries of relief came from the youths as they saw that instead of
crashing into the black mass, they were passing through it.

"As if a million pounds were lifted off my back," gasped Joe. "I
thought we were goners sure."

"Would be if that were a mountain," Bob said. "As it is, we're no
worse off than before. It's a lot darker, though."

Karl sought to pass out of the cloud by gaining altitude, but he soon
saw that this was useless. Still, he thought it best to fly higher.
There was a limit to the height he could safely reach, however, for
neither himself nor the youths were using oxygen, and the high rare
air was not sufficient to supply enough necessary to the human body.

"I'll have to trust to luck, I guess," he said through the telephone.
"We may make it all right."

"Karl didn't say that any too hopefully," remarked Joe. "Do you
suppose he really fears disaster?"

"It seems like it." Bob was terribly worried. He did not have much
hope of getting out unharmed.

Then suddenly the air travelers received a surprise. The cloud that
had a few seconds before been so heavy and dense quickly thinned out
until it passed from view. Once more the blue sky was visible.

The explorers could hardly believe their eyes. Had they actually
emerged from what seemed like certain disaster? It was some time
before anyone spoke.

"What do you think of that one?" Karl Sutman's voice was the first to
break the silence. "Couldn't have been much worse suspense, could
there?"

"We didn't see that we had much chance," said Joe gravely. "And when
we saw that black mass----"

"We're out of it now, though," the aviator said. "So why not dismiss
it from your mind?"

He was put out to think that the monoplane was several miles off its
course, but he refused to let that worry him, since they had had such
a miraculous escape.

It did not take long, however, to make up for the lost time, for the
young pilot well exceeded the hundred-and-fifty-mile-an-hour cruising
speed of the monoplane.

As best he could he kept the machine as near the mountain tops as was
safe, so as to make it unnecessary to use oxygen. Getting out the
masks and tanks would require much time, and that was what they did
not want to spare.

"There's Mount Panta," observed Joe, his eyes on a massive peak. "Why
can't we stop and see the archæologists--for only a few minutes, I
mean? I suppose they're still looking for Inca ruins in this region,
aren't they?"

"Yes and no," laughed Karl. "I mean this: they're still searching for
ruins, all right, but not in this part of the Andes. I stopped to see
them just before I flew after you fellows, and they told me they were
going to leave for another section over to the east."

"Wish we could have got in touch with them," said Bob. "We have
information about Inca secrets that would make them jump up and down
with joy. Maybe we can tell them later, though."

A half-hour of flying from Mount Panta brought them within sight of
the Comberciato River, along whose banks somewhere the youths' fathers
and Mr. Wallace were staying.

Suddenly Bob and Joe cried out in delight.

"Dad! Mr. Lewis! Mr. Wallace!" said Bob happily.




CHAPTER XXIX

The Horrible Beast


The joy of Bob and Joe at seeing the naturalists was certainly great.
After those strenuous weeks in the mountains, the youths had been
growing anxious to be with their fathers and Mr. Wallace again. Now,
as they viewed the men waving at them from below they were overly
anxious to land.

There was a wide open place directly under them, and to this Karl sent
the monoplane. When finally it came to a stop, Bob and Joe dashed out
and ran to meet their fathers and the scientist from Chicago.

"Boys!" cried Mr. Holton, too joyful for words.

He and Joe's father and Mr. Wallace fairly ate the youths up in their
happiness at seeing them alive and well.

"You came through all right, I see," laughed Mr. Lewis, after the
first few remarks were over. "What kind of a time did you have? And
the treasure--did you find any?"

"Look," returned Joe and showed them the box of gold beads.

The men cried out in astonishment. Unlike Karl Sutman, they had
expected the youths to return without having found anything of value.

"You were successful, all right," observed Mr. Holton. "Tell us about
your adventures."

While the men listened intently, the boys related their experiences
from the time they had left Cuzco with Dr. Rander.

When at last they were finished, the naturalists shook their heads
gravely.

"It was all very interesting, but at the same time it was dangerous,"
said Bob's father solemnly. "Afterward we wished you fellows hadn't
gone."

"But they came through all right--and brought us a white condor at
that," beamed Mr. Lewis. "No doubt this is the only _condor real_
we'll see. We did shoot two of the more common kind, though."

"Did you get many specimens?" inquired Bob.

"Come and see for yourselves," smiled his father and led the way to
the naturalists' camp.

"Great Scott!" cried Joe, surprised at seeing such a vast number of
wild animals and birds. "This region must teem with all sorts of
animal life."

"It does," returned Mr. Wallace. "And that reminds me. We were going
out in search of a black 'spectacled' bear this afternoon. We'd like
to have you go with us, if you will."

"Will we?" cried Joe. "Does a cat miaow?"

The naturalists had everything in readiness for the bear hunt. They
had but to eat a lunch and then they would be ready to start the hunt.

Mr. Lewis had heard reports from natives that one of the huge animals
had been seen in a dense woodland beside the river. To this spot the
party went, rifles in readiness.

When they entered the jungle they were met with total surprise. Beside
an opening in the hillside was the bear, crouching low for a charge!

There was only a moment to act.

"Shoot!" cried Joe fearfully. His rifle had been dashed from his grasp
by a protruding tree bough.

Bob had taken a position a number of yards from the others. He had
intended to search another part of the jungle. The youth was holding
his gun in readiness now, looking for a chance to take aim.

Then he thought the time had come to fire, and pulled the trigger.

Bang! The rifle spoke, but the bear had suddenly turned, and the
bullet missed.

With a snort of rage the huge beast turned on Bob, showing its
terrible teeth savagely.

Bob saw the danger and was hurriedly trying to work the bolt on his
rifle. But unfortunately the mechanism had jammed.

Helpless, the youth would be at the mercy of those terrible teeth and
claws! Already he could imagine the horror of what would follow.

Bang! Bang! Two rifles barked, and each bullet found its mark. Another
shot and the huge bear fell dead, almost at Bob's feet.

"Whew!" gasped Karl Sutman, holding his smoking rifle. "Another narrow
escape to add to you fellows' already long list."

"We're piling 'em up thick and fast," said Bob. He could laugh, now
that the danger was over.

They made their way back to camp, after having cut off the great skin.
It was at once placed in preservative.

"One more prize specimen to add to our collection," said Mr. Wallace.
"I'm betting that Bob and Joe will prove a valuable asset to the
expedition during the next few weeks. They're both good shots, and
they have plenty of courage."

Indeed the youths tried to justify themselves of this tribute, and
were successful in doing so. During the eventful days that followed
they collected many specimens for the scientists, including about
every form of life they could see in this wild region. Often they made
long excursions into the adjoining mountains in search of new wild
creatures, and usually found them. Taking moving pictures also
occupied their time.

But although the naturalist party was meeting with success in its
search for fauna, the men did not wish to remain here too long, for
other duties at home prevented it. Especially was Mr. Wallace anxious
to get back to Chicago.

It was arranged one day that he and Bob and Joe go with Karl Sutman in
the monoplane back to the United States, preceding Mr. Holton and Mr.
Lewis, who would arrive later by steamship. The youths' fathers took
it on themselves to attend to getting the specimens on muleback to the
coast, where they would be loaded on the vessel.

The four leavetakers were given an affectionate farewell by Mr. Holton
and Mr. Lewis, who expressed hope that their sons and friends would
arrive in the United States without mishap.

On the way to the coast the air travelers stopped to see Dr. Rust and
others of the archæologist party. Bob informed them of the Inca
secrets he and his friend had found, and gave them the map he had made
of the region. The scientists' delight far exceeded the boys'
expectations. They literally mauled the youths in their intense
enthusiasm.

When the chums, Mr. Wallace, and Karl climbed into the cabin, the
scientists gave them a royal send-off, wishing them a safe journey.

And safe it proved to be. Karl's ability as a pilot was greatly
appreciated as they flew toward the United States, which they reached
without incident.

"Now to get home," said Bob, as he and Joe and Mr. Wallace hailed a
taxi. The naturalist intended to spend another day or so with the boys
before boarding a train to Chicago. Karl Sutman left them at the
airport, promising to get in touch with them within the next few days.

At their homes Bob and Joe and their friend were given a profound
welcome by Mrs. Holton and Mrs. Lewis, who were desirous of knowing
about their experience.

"We had a wonderful time," said Joe, as they all sat in the Lewis
living room. "And we met with adventures aplenty. There's nothing
quite like exploration, especially when you're looking for ancient
secrets."




      *      *      *      *      *      *




Transcriber's note:

The four books in this series have been transcribed in the same
manner. This means that in some books, table of contents and or/list
of series names have been added.

Except in cases of obvious typographical errors, archaic and
inconsistent spelling has been retained.