asked.

"Don't know," said Stone. "I haven't been given much chance to talk to
'em, have I? But that German is smart, and he may suspect. But"--and
with this statement he set at rest a part of Bob's fears--"my bed is
pretty close to this room an' I have pretty good ears. I overheard
some things that Morales and Von Arnheim couldn't hear, especially
when you used the radio to call your father. Anyhow, I thought it was
your father. Mostly you spoke in code, but I heard you call him 'Dad'
a couple of times."

The three chums looked at each other, nonplussed. Stone laughed.

"Until I made out who you were," he said, "I thought you were some
wild-eyed kids looking for adventure an' comin' to the right place to
find it. But once I got a suspicion, it was easy to figure out the
rest. You see, I knew about your owning the airplane that Von Arnheim
stole, an' about your radio stations. When you started the generator
that showed me you knew something about radio, an' that was another
clue.

"So I just put two an' two together. Anyhow, it finally came to me who
you were. Am I right?"

"Yes," said Jack, taking the initiative as Stone concluded, "you are
correct. It is my father who is held prisoner by the Mexicans, and
these are my chums."

Jack regarded the other searchingly.

"We're in trouble," he said, simply, "and we need help that you could
give us. How closely are you tied up with the rebels? You're an
American and we are Americans. Does that mean anything to you?"

"Yes, kid, it does," said Stone. Despite the fact that he was only
seven or eight years older than the three chums, he had led a roving
life that had given him a world of experience and an older viewpoint,
and he persisted in regarding them as youngsters. "I'm strong for the
good old U.S.A.," he continued.

"But don't get me wrong. These are fine people down here, and don't
you believe they ain't. Their standards aren't American standards
either in manners or politics. But, just the same, they're good folks,
and don't you let anybody tell you different. I wouldn't turn against
them for anything. So, although your fathers have lots of
money"--here he looked fixedly at Bob, who felt uncomfortable
remembering his father's authorization to offer Stone money to help
them--"well, don't offer me any, that's all."

Bob was silent, but Jack again stepped into the breach.

"Good for you," he said warmly. "I'm glad to hear you talk that way.
But"--and here J