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!”