e felt.

"Oh, don't worry," said Mr. Jenks, quickly, "we're not going to toss you
overboard. We're not as desperate as your crowd. But we're going to
get rid of you, and then go on before you can send any word to your
confederates. We'll put you off in the most lonesome spot we can find,
and I guess you'll be some time getting back to civilization. By that
time we'll have the secret of the diamonds."

"You never will!" declared the man, firmly. And he would say nothing
more, though by threats and promises Mr. Jenks tried to get from him
something about the men in with him, and where the cave of the diamonds
was located.

Heavily bound with ropes the man was locked in a small closet, to be
kept there until a favorable spot was reached for letting him go. Mr.
Jenks' plan, of dropping him down in some place where he would have
difficulty in sending on word to his confederates was considered a good
one.

Three days later, in crossing over a lonely region, near the Nebraska
National Forest, Farley Munson, which was one of the names the spy went
by, was dropped off the airship, when it was sent down to within a few
feet of the earth.

"It will take you some time to get to a telegraph office," said Mr.
Jenks, as a package of food, and a flask of water was tossed down to the
stowaway. He shook his fist at those in the airship, and shouted after
them:

"You'll never discover the secret of Phantom Mountain!"

"Yes, we will," declared Tom, as he sent the Red Cloud high into the air
again.

CHAPTER XI--A WEARY SEARCH

During the three days when the stowaway had been kept a prisoner, the
Red Cloud had made good time on her western trip. She was now about two
hundred and fifty miles from Leadville, Colorado, and Tom knew he could
accomplish that distance in a short time. It was necessary, therefore,
since they were so close to the place where the real search would begin,
to make some more definite plans.

"We will need to replenish our supply of gasoline," said Tom, shortly
after the stowaway had been dropped, and when the young inventor had
made a general inspection of the airship.

"Is it all gone?" inquired Mr. Damon.

"Not all, but we will soon be in the wildest part of the Rocky
Mountains, and gasoline is difficult to procure there. So I want to fill
all our reserve tanks. But I would rather do that before we get far into
Colorado."

"Why?" inquired Mr. Parker.

"Because airships are not so common but w