y'll shoot defenseless men, and they
may listen to reason, and give Mr. Jenks his rights--tell him how to
make diamonds in return for the money he gave them."

"I don't believe those scoundrels will listen to reason," replied the
diamond man, "but I agree with Mr. Damon that we ought to go on. We may
find some other means of reaching the cave--if we can discover it, and
we'll take a chance with the men."

"Forward it is, then!" cried Tom. "I have a revolver, and I can supply
one of you gentlemen with another. They may come in useful in an
emergency. Let's go back to camp, take a little lunch in our pockets,
and try to scale the mountain."

They were soon on their way up the dizzy path once more, and, as they
advanced, they found it growing more and more dangerous. In some places
they found it almost impossible to get around certain corners, where
there was barely room for their feet. As Tom remarked grimly, a fat man
never could have done it. Fortunately they were all comparatively thin,
for their hard work, and not too abundant food, since they had left the
airship, had reduced their weight.

Up and up they went, higher and higher, sometimes finding the path wide
enough for two to walk abreast, and again seeing it narrow almost to
a ribbon. They hardly dared look down into the chasm at their left--a
chasm filled, in part, with the rocks and boulders tossed into it by the
lightning bolt.

Tom was in the lead, and had just made a dangerous turn around a
shoulder of rock--one of those places where he had to extend both arms,
and fairly hug the cliff before he could get around.

But, when he had made it, and found himself on a broad pathway, cut
in the living rock, he gave a great shout--a shout that caused his
companions to hasten to his side. They found the young inventor pointing
to a clump of bushes and small trees.

But it was not the shrubbery that Tom desired to call to their
attention. They saw that in an instant, for, dimly seen through the
leaves, was something black, and, as they looked more closely, they saw
that it was a great hole in the side of the mountain--a vast cavern,
opening like a tunnel.

"The cave! The cave!" cried Tom. "The diamond makers' cave!"

Hardly had he spoken than two men, each one carrying a gun, showed
themselves in the mouth of the cavern, and, instant later they both ran
toward the little party of adventurers.

CHAPTER XVII--THE PHANTOM CAPTURED

Surprise held Tom