hose red and blue lights?" asked Will.

"Certainly we did," replied Cameron.

"Well, they told the story of what has taken place since the boys left
the cabin to follow your footsteps last night, so you may as well save
your breath. Lies won't help you any!"

However, the lads managed to bring the two men closer to the fire and
then set about piling on more green boughs.

"Now," Will said, as he stood regarding the two columns of smoke with no
little satisfaction, "if our friends are within five miles of us, they
ought to understand that we are in need of a little friendly
assistance."

Time and again the two boys went back to the place where the cavern had
been and listened patiently for some further indication that their
friends were still alive. Several times they heard the rumbling of a
voice but they could not distinguish the words of it.

Finally Will went back to where Cameron lay on the ground by the fire
and asked abruptly:

"Is your name Garman, Cameron or Brooks?"

The fellow gave a quick start of surprise but made no answer.

"Is this man Fenton the clerk who stole the machine drawings?" was the
next question. "Where are the plans now?"

"I don't know anything about any plans!" declared Cameron.

"What do you fellows expect to do with the plans?" asked Will.

"We haven't got them!" was the surly reply.

"Don't lie about it!" Will advised. "We know that the plans were sent to
Fenton's employer and that Fenton stole them."

"How do the plans concern you?" demanded Cameron.

"We don't want the plans because they are alleged to represent a
valuable invention," Will replied. "We want them because they are needed
in the criminal court of Chicago."

"I suppose you boys planned this costly and dangerous expedition for the
purpose of seeing how the plans look!" sneered Fenton.

"That's about the size of it!" replied Will.

"Well, we don't know anything about the plans!" declared Cameron, "and
we wouldn't give you any information on the subject if we did!"

"All right," Will replied. "We can tie you up out here and the mosquitos
will do the rest!"

Before Will could ask the question which was on his lips, three quick
pistol shots came from the south.

"There!" the boy said excitedly, "the signals have brought a response!"

"Friend or foe?" asked Ed.

"That's more than I know!" Will replied.

CHAPTER XX

DOWN IN THE CHASM

When Tommy, Frank, Sam and the doctor started toward the