"You've hit it," Scotty agreed.

Rick explained to Bennett about the ghosts and the cart, and then added Belsely's reports on the times when two or three ghosts had walked the fields without a cart. "Scotty and I saw three of them once, and it's a cinch they were using a survey meter to check the ground for radioactivity. But why? That's what has us going around in ghastly, ghostly circles. Why spread carnot.i.te and then come back to measure it?"

Bennett smiled. "I think I know, but I'd like to see this mine of yours.

Can it be arranged?"

Scotty said swiftly, "I'd better act as a lookout to intercept the Frostola man if he comes. I'll delay him while you two go into the mine." He was gone at a ground-eating pace.

Rick led the AEC man to the hidden mine entrance. "I don't have a flashlight with me."

"No need. What we want will be right at the entrance, I'm sure."

They crawled in on hands and knees, the AEC man pushing his bag before him. Inside, he looked around and selected several small pieces of rock.

"We'll check the samples, but it's just a formality. I recognize this stuff. It's carnot.i.te. You can see the yellow streaks clearly. That's the uranium color. Of course the rock is mostly gray, so that's the color of the powdered ore."

"Then the mine really contains radioactive ore?" Rick asked eagerly.

"Only what was put here, I'm afraid."

With this cryptic comment Bennett opened his case and checked the samples. Rick watched the meter climb. They were radioactive, all right, but of low ore level, not at all dangerous.

"We'd better get out of here," Bennett said. "I'd rather not be discovered at this point. When your friend Scott comes back I'll tell you what has happened."

Scotty rejoined them as they reached the cornfield again. They walked with Bennett to his car, and listened to an explanation that made everything clear.

"This is a game as old as mining," Bennett told them. "It has happened before, and it will happen again. Uranium is the treasure metal now, where gold used to be. So the game uses uranium. The game is known as salting."

"Salting?" Scotty asked. "I've heard it in connection with gold mines, but I can't remember exactly what it means."

"It means putting evidence of high-grade ore in a likely place, but one which actually contains no real pay dirt. For instance, in country where gold may be found, the technique for salting used to be firing gold nuggets into the ground with a shotgun, by replacing the buckshot with the nuggets. Then, when the victim was allowed to try panning gold for himself, he'd come up with the nuggets and think he was getting natural gold."

"And in this case, powdered carnot.i.te was used in the fields, and chunks were put in the mine, to make victims think uranium was present," Rick added. He could see the picture pretty clearly now. "The carnot.i.te was put in and then the field was planted with corn to make it look as innocent and natural as possible, I suppose."

"That's how I figure it. There's no uranium around here, except for the very small percentage that one can often find a.s.sociated with some varieties of lead. We'll find that someone has been pulling a very cute confidence game, bringing clients here by night, showing them the radioactivity--by letting them hear the clicks in the earphone of a counter, probably--and then selling them either shares in a mine or pieces of property."

"And using the ghost to scare the townspeople away so there would be no interference," Rick finished. "But how can we prove all this?"

"You won't have to. I brought a man with me, and dropped him off in town. His name is Joe Taylor, and he's an FBI agent."

"The FBI?" Scotty looked puzzled. "But bunco games or con games, whatever you call them, aren't a federal offense! How does the FBI get in on it?"

"Because the carnot.i.te was federal property. It was stolen from a loading platform at our Grand Junction facility. We know this, because there is no record of any transaction, and we can identify the source by the chemical composition of the sample."

"But how could anyone steal stuff from AEC?" Rick asked.

"Easily, in this case. There is no purpose in protecting ore with the same security we give the processed stages, like green salt, for example. No one could possibly steal enough ore to do any good, because it takes many tons to produce even a gram of uranium. Ore moves by carloads, on normal railroad or truck bills of lading, from private companies who mine it. No security is required, you see, because no one has the capability of getting out the metal even if they could steal thousands of tons of ore."

Rick understood this. He had seen the plant at Oak Ridge where uranium was extracted by the gas diffusion method. The plant covered acres. Only a government could afford such a facility.

"But couldn't the carnot.i.te have been stolen from a privately owned mine?" he asked.

"Possibly, but we will a.s.sume it was in our hands when it was taken.

This is because we want to discourage this kind of thing, and the FBI taking action is very discouraging to thieves."

The boys appreciated this viewpoint. "I hope the FBI doesn't interfere with Rick's plan for exposing the ghost," Scotty said.

"I don't think you'll find Taylor hard to persuade. I'll suggest he stop by and hear your story. It will help him. Then you can outline your own plans."

"We'll be waiting," Rick a.s.sured the AEC expert. "Before you go, what's your idea about the changing number of ghosts? Was that when the clients were brought to see the Geiger counter work?"

"That would be my guess," Bennett agreed. "You'll probably find that the ghost took them on a conducted survey of the mine and the fields to show them what valuable property he was offering for sale--or for shares in a mine."

Scotty objected, "But the ghost wore the luminous blue head. Any clients would think that was mighty peculiar, to put it mildly, unless they knew they were being parties to something illegal."

Bennett chuckled. "It's one of the key factors in a really big con game to make the client think he is getting something for nothing, or maybe even a shade outside the law. Confidence men say that everyone has a 'little larceny in his soul.' I'm sure that's not true, but enough people do so that they can be swindled by an illegal offer."

Rick snapped his fingers. "Dr. Miller's property, and the fact that Hilleboe owned only part of the mine! That's the reason for the ghosts that walked by night. It has to be! The swindlers would tell their clients only part of the land was available and they needed funds to buy the rest of it--but the inspection had to be held by night to keep the owner from suspecting he had a uranium mine on his property."

Bennett asked, "Was Dr. Miller actually approached with an offer to buy?"

"Yes," Scotty replied. "It was a good offer, too. That must mean the swindlers were doing a good business and needed more land to sell."

"Not necessarily. They probably wanted the Miller property more as a safety factor than anything else, in case someone got wind of what was going on and tried to horn in. They probably didn't actually sell land, only speculative shares in a mine to be developed. That's the usual technique. The secrecy and mystery, and having a phony ghost for a guide, were just added elements of drama to help with the selling. The clients thought they were in on a great big secret."

Rick grinned. "They were. We've just managed to untangle it, with your help."

"Delighted," Bennett said. "But you'll find Taylor much more of an expert than I. See you later, boys, I'm sure."

They watched as the AEC man drove off. "I'm pretty sure we have the answers," Rick said happily. "Hilleboe probably is the boss, since he owns the property, but Collins is in on it to some extent because he knew about the upper mine tunnel, and acted as agent for Hilleboe. And our pal the Frostola man is in it up to his hip pockets."

"He's the ghost," Scotty agreed. "Both in the tunnel when the machine is run, and at night when the ghost walks. At least he is part of the time.

Of course there's no reason why someone else couldn't be the ghost, too, maybe two or three different people."

"Someone else was the ghost the first night," Rick remembered, "because the Frostola man was watching."

"Good thing we don't have to prove any of this," Scotty concluded. "The FBI is on the job. They'll get the proof."

"But we're the ones who'll bury the ghost for good," Rick promised.

CHAPTER XX

Death of a Ghost