The shaft went straight in, past the range of light filtering in from the entrance. Nowhere was there a sign of human occupancy or activity, except for the ancient marks on the tunnel walls made by tools in the hands of miners long dead.

"Nothing here," Rick said, and his voice was lost in the emptiness of the shaft.

Scotty grunted. "Another dead end. Okay, where did the ghost come from?"

Rick didn't know. He couldn't even imagine. He puzzled over it as they walked outside, then suddenly snapped his fingers. "Did you see any sign of water in there? Or a pipe?"

"No. It was dry. No pipes. Why?"

"How was the original artesian well driven? Right into the hillside? If so, why didn't the mine tunnel strike water?"

Scotty scratched his chin. "Now that you mention it, I haven't the faintest idea. Have you?"

"Negative. I can't ever remember having so few ideas. But it's strange.

We'll have to ask Dr. Miller about it."

"Maybe the answer is deeper in the mine," Scotty replied. "Let's go back and see."

Rick reminded him that they had no lights. "I suppose we could make torches out of junk from the trash cans."

"Easy, if we can find some newspapers."

There were several trash cans spotted around the picnic area, and it was indicative of the kind of neat people in the vicinity that they were used. There was no litter.

The second can yielded two entire newspapers, one a bulky edition of a Washington paper, the other a ten-page local sheet. The boys split the papers evenly, then rolled them tightly. They frayed one end with a jackknife to make the torch.

"Got a match?" Rick asked.

Scotty looked at him blankly, then grinned. "No, have you?"

"No match, no flint or steel, no ... hey, wait! I've got a pocket lens!"

Rick's enthusiasm for microscopy had extended to the purchase of a twelve-power pocket lens to supplement the microscope Barby had given him. The pocket lens was used for examining specimens before taking them home for closer scrutiny under the more powerful instrument. Rick had not yet gotten used to carrying the small lens and had forgotten it until the need for a burning gla.s.s arose.

He took the lens from his watch pocket and unfolded it from the protective metal case. It focused the sun's rays to a pinpoint of intense light and heat, and the charred paper then burst into a tiny flame. Rick blew the flame into life, then put his lens back for safekeeping.

"Nothing like the scientific method," he told his pal. "Who needs matches? Come on. Let's burn that ghost out of there."

Scotty grinned. "Nothing like luck," he corrected. "Okay, I'm right behind you."

They retraced their steps into the mine. Rick noted as they went through the entrance that the old mine timbers were pretty well rotted through.

He guessed that the mine had been boarded up because it was unsafe. He and Scotty would have to be careful.

In a few moments they were in deep gloom, only the smoky, fitful flicker of Rick's torch giving them light enough to see by. The newspaper wasn't burning very well, probably because he had rolled it too tightly. They could see only a trace of daylight.

The old shaft turned at nearly right angles where a geological fault had forced the Civil War miners to change directions in order to follow the vein of good ore. The turn cut off most of the light, except for the waning flicker of Rick's torch. Scotty hurriedly held his own torch to the flame to light it.

Rick was never sure what happened at that point, whether Scotty's torch pushed too hard and extinguished his own, or whether a sudden icy wind blew through the mine shaft. He knew only that they were instantly in darkness, while faraway ghostly laughter echoed in their ears!

CHAPTER V

Night Alarm

Rick lathered a hot dog with mustard and took a satisfying bite. It was a down-to-earth hot dog with no mystery, no eerieness about it, for which he was grateful. He hadn't admitted it, but the incident in the mine had shaken him.

Dr. Miller pa.s.sed the milk pitcher to Rick, then asked, "Are you certain you heard laughter? It wasn't a trick of the wind?"

"I'm sure it was laughter," Barby said solemnly. "Captain Costin was laughing at mortals who dared to enter his tomb."

Rick glanced at his sister, hoping she was joking. She wasn't. "I'm not certain," he admitted. "It all happened at once. I mean, the torch went out, there was a sort of sudden breeze, and we got out of there into the daylight."

He had a mental image of he and Scotty executing that ancient and honorable maneuver known as getting out of there! They had reached the mine entrance in a dead heat, probably breaking several world's records for foot racing.

"We didn't stop to listen," he added with some embarra.s.sment. "We just got."

"Well, I should think so!" Jan Miller said vehemently. "It's a wonder your hair didn't turn white."

Scotty raised a hand and ruffled his dark crewcut. "Didn't it?" he asked ruefully. "I took it for granted that it had."

Dr. Miller chuckled. "Put on a few more hot dogs," he called to his wife. "These boys need nourishment. They've been through an ordeal." To Rick and Scotty he said seriously, "You needn't be embarra.s.sed. The fear of the unknown, combined with the fears we have of closed places, almost complete darkness, and our own physiological reactions to the unexpected make us do our thinking with our legs instead of our heads in some situations."

It was neatly put. Rick acknowledged the scientist's statement. "It isn't as though we had been scared away for good. We're going back, equipped with lights a ghost can't blow out."

"And I'm certain you'll find nothing but an abandoned shaft," Dr. Miller replied. "After all, the dust showed no sign of human occupancy, you said."

"Ghosts don't leave tracks," Barby murmured.

Scotty accepted another hot dog from Mrs. Miller. "Thank you. Look, everyone, we can make two a.s.sumptions. Either that the ghost is real, in which case we call in the Society for Psychic Phenomena, or that the ghost is a man-made thing, in which case we search for the man."

"I'm still not buying a.s.sumption number one," Rick stated flatly. "My hair may be white, or close to it, and I'm ready to admit that the apparition is a mighty convincing spook, but I don't really _feel_ it's a ghost."

Jan Miller spoke up. "Rick's hunches are pretty good. If he doesn't believe in the ghost, it isn't just because he's a doubting Thomas. I think the boys should go ahead with their investigation on the a.s.sumption that the ghost is caused by someone."

Barby shook her head, more in sorrow than in anger. "I thought you had more faith than that, Jan."

"It isn't a question of faith," Jan explained. "It's a question of where you start. If we start by accepting the ghost as real, there's nothing we can do. Anyway, we invited the boys down to try to solve a mystery, didn't we? I guess that proves we didn't truly believe in the ghost."

Rick grinned at the dark-haired girl. "Okay, Jan. Now, to carry on where Scotty left off, if we a.s.sume the ghost is man-caused, we have to a.s.sume it isn't a practical joke, or that it is. What's the vote?"

"No evidence," Dr. Miller said thoughtfully. "It could be a practical joke, although it's an elaborate sort of thing. More complicated practical jokes than this have been pulled by expert jokesters. On the whole, however, I'm inclined to vote against the joke a.s.sumption on the grounds that it has been going on too long. Jokesters are not noted for their staying power. By this time the secret would be out, or we'd be having variations. The apparition wouldn't have fallen into a routine."

Dr. Miller had spotted exactly the thing that was troubling Rick. It was routine, but ghosts are traditionally far from routine. That was actually the biggest argument for a.s.suming that it was man-made, and that it was not a practical joke.

He voiced his thoughts aloud, then asked, "If man-made, and not a practical joke, what's the motive?"