“We built it to represent the geological structure of the country where the boundaries of Utah, Colorado, Arizona and New Mexico meet. This map and card explain—”

“I know the Four Corners,” grunted the little man as he sized up the tall, sandy-haired youngster. “Is your gadget accurate?”

“As accurate as we could make it with the survey maps we could find.”

“Hmmm.” Their visitor’s sharp eyes studied the gray mound. “What happens if I should drill an oil well here, in the northwest corner of the Navajo Indian reservation?” He pointed with a lean finger.

Sandy moved a pin to the spot he indicated, connected it to the control panel with a length of wire, and pressed a switch.

Nothing happened!

Quiz groaned. Why couldn’t the thing show off when they wanted it to?

“If you drilled there, sir, you’d just have a dry hole,” Sandy said with more confidence than he felt. “That location must be on the far fringe of the oil pool.”

“Right!” The little man grinned from ear to ear, showing a fine white set of false teeth. “I did drill a wildcat well there. She was dry as a bone. My ninth duster in a row.... Now what happens if I drill here, near the bed of the San Juan River?”

This time a bulb glowed brightly when they stuck their pin into the cardboard.

“We can’t be sure, sir,” Sandy hesitated. “We don’t know too much about geology. Besides, oil is like gold. It’s where you find it, and the only way you find it is by drilling for it. But I’d guess that, in the neighborhood you indicated, you’d stand a chance of hitting a thousand barrels per day.”

“Eight hundred and fifty barrels,” corrected the man in the blue jeans. “The well I drilled on the San Juan was the only thing that kept me out of bankruptcy.”

A blare of jazz from Pepper’s loud-speakers, now working in unison, cut off further conversation and gave the boys a chance to study their strange acquaintance.

“Why don’t you go over and take in that beam-of-light exhibit?” Sandy said when Pepper had brought the sound down to bearable levels. “It won first prize.”

“That pile of expensive junk?” sniffed the little man. “All the kid did was to borrow some apparatus from Red Cavanaugh’s Valley View Laboratory. If I know Red—and I do know the big fourflusher well—he didn’t make the boy do a lick of real research on it.... Oh!” Again that wide grin. “You think I’m crazy and want to get rid of me, don’t you? Here.”

He dug into his jeans and came up with a greasy card which read:

The Four Corners Drilling Company
John Hall, President
Farmington, N. M.

“Guess I should have got dressed up for this shindig,” Hall apologized, “but I just got in from Farmington. I read about your analyzer in the Valley View News when you won first prize at your high-school science fair last month. Used to live there. That’s why I still get the paper. Your dingus should have received first prize here too, instead of that voice-cast thing.”

“Say! You came all this way just to see our exhibit? Thanks!” was all Sandy could think of to say.

As the auditorium lights blinked to indicate that the fair was closing, Hall added, “Got time for a bite? I have a proposition I’d like to sound you out on.”

At a nearby diner, the oilman ordered full meals for all of them.

“Here’s my proposition,” he said when the boys couldn’t eat another mouthful. “I’m a small wildcat operator. That means I hunt for oil in places that are so wild and woolly that only wildcats can live there. Once or twice I’ve struck it rich. Should have retired then, but there’s something about oil exploration that gets in a feller’s blood. So I went out, drilled some dry holes, and lost my shirt.

“Right now I’m strapped until my new field pays off—if it does. But I think I’m onto something big in the Four Corners and I need help. You boys must have a working knowledge of geology to build an analyzer as good as that. How about working for me this summer?”

“Sandy’s the rock hound,” Quiz said and hesitated. “I ... I’ve only read up on it in books.”

“All I know is what Dad has told me,” Sandy remarked. “I couldn’t have built the exhibit without Quiz’s help.”

“Forget the mutual-admiration-society stuff,” said Hall. “Would you both like to spend your vacations in the Four Corners, working as roustabouts and helping me out wherever else you can? It won’t be easy. But when you get through you’ll know a lot about oil, geology, how to get along with Indians, and I don’t know what all.

“You’ll be out on the desert in all kinds of weather. You’ll chip rocks, hold stadia rods, sharpen tools and dig the trucks out of holes on those awful roads. Everything you learn will come in handy when you go to college.... You are going, aren’t you?”

Sandy nodded but Quiz shook his head miserably.

“I doubt it,” he said, “unless things at Dad’s restaurant pick up.”

“Nonsense,” Hall snorted. “You can get a scholarship in geology if you’ve had experience in the field. Tell you what: I know your father slightly—he serves mighty good victuals. I’ll go over to Valley View tomorrow and talk things over with him. I’ll bet we can work something out for you.

“Here’s another thing, though,” he went on thoughtfully. “I’ve got almost every cent I own tied up in oil leases right now. I can’t pay either of you very much—say forty dollars a week. You probably can do almost as well right at home.”

“I’d rather work with you than wait on table,” Quiz declared.

“Or cut lawns and things,” Sandy added.

“It’s settled then.” Hall shook hands gravely. “See you in Valley View.”

As they were leaving the diner, Pepper March came charging in with a flock of admiring Valley Viewers behind him.

“Wait up,” Pepper whooped, grabbing his defeated rivals as they tried to dodge past him. “My treat. Come have a Coke while I tell you about my good luck.”

“Another Coke!” Sandy groaned. He had practically lived on them during the science fair. But curiosity got the better of him and he went back to the counter, followed by Quiz. By the time he found a stool, Pepper was holding forth.

“You know Mr. Cavanaugh, the man I got some of the stuff for my voice-caster from?”

“The man from whom you borrowed all your equipment,” Sandy corrected between his teeth.

“That’s what you think, Honorable Mention.” Pepper turned to his admirers. “Anyway, he has a sideline: spends his summers hunting uranium. Also, he’s the same Red Cavanaugh who was All-American quarterback for State U. in 1930. He’s the fellow who ran three touchdowns against California in the Thanksgiving game that year.”

“There was a Cavanaugh who made All-American,” Quiz agreed as he scratched his round head, “but I thought....”

“See!” cried Pepper. “Quiz knows all there is to know about football. He’s heard about Red. Well, Mr. Cavanaugh attends all the Valley View games. Says he likes the way I run touchdowns.” Pepper leered at Sandy, who was not always the spectacular player that Pepper was. “Also, Mr. Cavanaugh appreciates the plugs I gave to his laboratory whenever I explained my voice-caster, so what do you think...?”

“He’s going to install you as a loud-speaker in one of his TV sets,” Quiz suggested.

“Nah!” Pepper stopped the laughter with a lordly,