eep us here forever.
They'll have to let us go some time." Following their capture, Folwell
and Munson, the latter the stowaway of the airship, had been in earnest
conversation regarding our friends, but what conclusion they had reached
the adventurers could only guess.

"And we didn't have time to examine the diamond-making machinery close
enough so that we could duplicate it if necessary," complained Tom, a
little later.

"No," agreed Mr. Jenks. "There are certain things about it that are not
clear to me. Well, I don't believe I'll have another chance to inspect
it. They'll take good care of that, though they seem to be getting ready
to make more diamonds."

"Perhaps they're going to manufacture a big batch, and then leave this
place," suggested Mr. Damon. "They will probably go to some other secret
cave, and leave us here."

"I hope they untie us before they leave, and give us something to eat,"
remarked the young inventor.

For two hours longer the captives lay there, in most uncomfortable
positions. Then Folwell and Munson, leaving the group of diamond makers
who were grouped about the machinery, approached the captives.

"Well," remarked Munson, "we got ahead of you after all; didn't we. You
thought you had our secret, but it will be a long while before you ever
make diamonds."

"What are you going to do with us?" asked Tom.

"Never mind. You came where you had no right to, and you must take the
consequences."

"We did have a right to come here!" exclaimed Mr. Jenks. "I am entitled
to know how the diamonds are made. I paid for the information, and you
tricked me. If ever it's possible I'll have the whole gang arrested for
swindling."

"You'll never get the chance!" declared Folwell. "You were given some
diamonds for the money you invested, and that makes us square."

"No, it doesn't!" declared Mr. Jenks. "I invested the money to learn how
to make diamonds, and you know it! You tricked me, and I had a right
to try to discover your secret! I nearly have it, too, and I'll get it
completely before I'm done with you!"

"No, you won't!" boasted Folwell. "But we didn't come here to tell you
that. We came to give you something to eat. We're not savages and
we'll treat you as well as we can in spite of the fact that you are
trespassers. We're going to give you some grub, but I warn you that any
attempt to escape will mean that some of you will get hurt."

He signalled to some of his confederates. These men