penetration into the mine on their last visit and
found the remains of their torches.

"No change. Thought they might have been chewed by ghosts," Scotty
commented.

"Newsprint doesn't taste good," Rick replied. "Do ghosts have teeth?"

"Nope, just an icy breath. Do you remember any smell, by the way? When
we got hit in our faces?"

"Something sort of sweet?"

"Yes. I wasn't thinking about smelling, and I didn't notice especially,
but I sort of recall a nice odor."

Rick thought he remembered it, too. "We'll look up methyl chloride in
the dictionary," he promised. "That will tell us if it has an odor."

The mine took a sharp turn. "They lost the vein here and had to chew out
some rock to find it again," Rick pointed out. "Notice everything is on
one level? Must have been just one vein. It ran out and the mine closed
down."

"Looks that way," Scotty agreed. "How far have we come?"

Rick hadn't kept track, but he estimated they were perhaps halfway under
the hill. "This must end somewhere," he said. "Notice there isn't any
water at all, not even seepage? I'm still baffled by that spring and the
pipe."

They traversed another hundred yards in silence, flashlights constantly
scanning the mine. There was nothing out of the ordinary, no sign of
ghost, projector, or even of human visitation for dozens of years.

"We're on another wild-goose..." Rick began. He never finished, for
sound suddenly reverberated through the mine, the sound of rock crashing
downward.

Both boys turned and ran back toward the entrance, afraid of what they
would find. Long before they reached it, billowing clouds of dust told
them what had happened.

Their racing legs confirmed it as they came to a stop against rock that
choked the tunnel from top to bottom.

[Illustration: _The timber had given way. They were trapped!_]

The timbers had given way. They were trapped!

CHAPTER XVII

In Darkness

For one despairing instant the two peered at the fallen rock through the
thick haze of dust, then Scotty snapped, "Back into clean air."

They retreated the way they had come. Rick clicked off his flashlight
instinctively. They might need it.

When clean air was reached again they stopped and Scotty swept his
flashlight beam over the rocky floor. "Pick a seat and get comfortable.
We'll be here for a while."

"We won't get out of here by sitting down," Rick replied.

"No, and we won't do much until the dust settles, either. R