Scotty said. "At least nothing I can see. We'll have to
try the mine itself."

They had replaced the boards at the entrance, simply pushing the nails
back into the holes from which they had come. They pulled the boards
aside and saw footprints--and not their own!

"Visitor," Scotty said with excitement.

Rick noted the size of the tracks. "And a big-footed one, too. Makes our
tracks look small."

Scotty pointed. "He came out again, whoever he was. Let's see how far he
went in."

The tracks told the story clearly and quickly. The visitor had gone in
about twenty feet, and had then returned to the outside. One glance told
the boys why.

The mine was timbered, with uprights and overhead beams spaced about
every ten feet. Where the visitor had stopped, the mine timbers were
supporting a big piece--or many pieces--of the rock overhead. Rick
guessed that the heavy rain, working through cracks, had loosened a
section and let its weight fall on the overhead crosspiece. It was also
clear that the timbers would not support the weight for very long. They
were rotten, and wet with the constant seepage of water.

"Must have been one of the Sons of the Old Dominion who wandered in for
a look," Rick suggested. "He saw it wasn't safe and went right out
again."

"Something like that," Scotty agreed. "And it isn't safe. Those timbers
would go if anyone breathed hard at them."

"Then let's not breathe hard," Rick said.

"Meaning that we're going in, anyway."

Rick pointed out, with what he thought was complete logic, that the
timbers had held the roof up since the rain, and that collapse surely
wouldn't take place in a minute or two. He concluded, "And if we're
going to find any kind of clue to a projector, it has to be in this mine
somewhere."

"Then let's not linger," Scotty said. "And for Pete's sake don't stamp
your feet when you go by the timbers. A little vibration would send them
down for sure."

Rick asked, "What were the wind and the laughter the last time we were
in here?"

"Imagination," Scotty replied. "Let's keep it under control this time."

"I'm with you. And ghosts don't blow out flashlights, so let's go."

They moved cautiously past the unsafe place, lights probing the tunnel
walls for a sign of anything unusual or worthy of attention. Now and
then they reached a bay where ore had been taken out, or a jog in the
tunnel where the miners had lost the ore vein temporarily. They reached
the spot of their