en knocked down by the fleeing man.

"Look out, Mr. Jenks!" cried Tom, to warn those on guard at the door of
the storeroom.

There was the report of a gun, some excited shouts, and when Tom could
scramble to his feet, and rush out, he beheld Mr. Parker calmly sitting
on a struggling man, while Mr. Jenks held a gun, that was still smoking.

"We caught him!" cried the scientist.

"Anybody hurt?" asked Tom, anxiously.

"No, I knocked up his gun as he fired," explained Mr. Jenks. "Where are
the ropes, Tom?"

The cords were produced and the man, who had now ceased to struggle,
was tightly bound. He uttered not a word, but he smiled grimly when Mr.
Damon remarked:

"I guess I'll go back in the storeroom, Tom, and see how much food he
ate."

"Oh, I guess he didn't take much," declared the lad. "He wasn't there
long enough."

"Well, Farley Munson, so it's you, is it?" asked Mr. Jenks, as he
surveyed the prisoner.

"Do you know him?" asked Tom, in some surprise.

"He was in with the diamond makers," said Mr. Jenks. "He was one of
those who took me to the secret cave. But it will be the last time he
ever goes there. How high up are we, Tom?"

"About two miles. Why?"

"I guess that will be far enough to let him fall," went on the diamond
seeker. "Come on, Mr. Damon, help me throw him overboard!"

"You--you're not going to throw me over--with the airship two miles
high; are you?" gasped the man.

"Will you tell us what we want to know, if we don't?" asked Mr. Jenks.

"What do you want to know?"

"How you got aboard, and what your object was in coming."

"That's easy enough. I had been hanging around the shed for several
days, watching a chance to get in. Finally I saw it, when that colored
man went to feed his mule, and I slipped in, and hid in the airship. The
stores were all in then, and I stowed myself away among the boxes. I had
food and water, so I didn't touch any of yours," and he looked at Mr.
Damon, who seemed much relieved.

"And what was your object?" demanded Mr. Jenks.

"I wanted to prevent you from going to Phantom Mountain."

"How?"

"By destroying the airship if need be. But I hoped to accomplish it by
other means. I would have stopped at nothing, though, to prevent you.
You must keep away from there!"

"And if we refuse?" asked Tom.

"Then you'll have to take what comes!"

"But not from you!" exclaimed Mr. Jenks. "We're going to get rid of
you."

The man's face showed the alarm h