arms behind him and began tying them with his belt.

Meantime Jack was getting the better of his man, the Mexican. But
Frank, slightest of the three boys, was putting up a losing fight
against the German. The latter had him down and was kneeling on his
chest with his hands throttling the boy. Frank's face was purple and
the breath was whistling in his throat, while his efforts to throw the
other off were becoming more and more feeble.

Tom Bodine took in the situation and sprang forward, clubbing his
revolver. He brought it down on the German's head. There was a
sickening thud. One blow was enough. The German's hands relaxed their
grip on Frank's throat, and he rolled over unconscious.

At the same moment Jack pinioned the arms of the Mexican, and the
latter lay helpless.

The fight was over.

CHAPTER XIX

RESTING UP

Swiftly Tom Bodine trussed up the unconscious German with the man's
own belt, while Jack similarly treated the thoroughly cowed Mexican,
Morales. Meanwhile, Bob went to Frank's aid, assisting him to a chair,
bringing him water from a spring in a corner of the inner cave and
fanning him with his sombrero.

None of the three boys had suffered more serious injuries than
bruises, but Frank had been badly battered in the encounter with his
heavier opponent and the muscles of his left shoulder had been
severely strained.

Despite the mauling he had received, Frank wanted to go and inspect
his beloved airplane at once and Bob, the co-owner with him, was
equally eager. Jack, however, protested.

"No, sir," said he firmly, "you are in no condition to go chasing off
down this rocky slope. The airplane isn't going to fly away. It's in a
pocket in the hills that nobody is going to discover. And, anyhow,
there is nobody around in this desert place to do any discovering.

"Moreover," he continued, "it is almost morning now. We all have been
riding all night and with this fight coming on top of everything else,
we are thoroughly tired out. So, instead of any more conversation
tonight, I propose that we turn in and go to sleep, leaving one man on
guard. At the end of two hours he can call another fellow, and in that
way we can all get four or five hours sleep. I'll take the first watch
and--"

At that moment a groan from one of the prisoners on the other side of
the room interrupted, and with an exclamation Bob started forward.

"Good gracious," he said, "I'd forgotten all about that chap. His ar