the empty air.

"What do you make of it?" asked Tommy.

"Is this Tunnel Six?" asked his chum.

"I don't know! If it is, we've seen the light the caretaker referred
to. We'll have a great story to tell in the morning!"

The boys stood in the darkness of the gangway watching the light for
what seemed to them to be a long time. Now the light advanced toward
them, now it receded. Now it lifted to the roof of the gangway, now
it dropped almost to the floor.

At intervals, the noises behind the cribbing to which Tommy had
referred were repeated, and the boys at last moved over so as to stand
with their ears almost against the wooden walls.

"There is some one behind the cribbing, all right!" Tommy declared.
"I hear some one breathing."

"Aw, keep still!" whispered Sandy. "If there is anyone there, you'll
frighten them away! I though I heard some one myself!"

"I'll tell you what I think," Tommy suggested in a moment, "and that
is that either Will and George, or both of them, beat us to this
gangway. They are hiding behind there on purpose to give us a scare."

"That's a dream!" replied Sandy. "We left them both asleep."