Jack and Bob were to make the attempt at the rescue of Mr. Hampton alone.  They were to fly to the Calomares ranch in the airplane with Bob at the wheel, as Jack was not so experienced a flyer.  Bob, on the other hand, knew his machine thoroughly, and was familiar with its every trick, a knowledge much to be desired as airplanes even more than motor cars and ships develop temperament and have got to be “humored,” so to speak.

Frank rebelled at the part assigned him.  He was to stay behind at the cave with Tom Bodine and Roy Stone, guarding the prisoners, Morales and Von Arnheim.  When they had rescued Mr. Hampton, Jack and Bob would take him in the airplane and start flying to the Hampton ranch.

By means of the radio in the airplane, which could send 150 to 200 miles, although it could receive messages from a much greater distance, the Hamptons and Bob would notify the party left behind in the cave.  Then Frank, Tom Bodine and Stone would ride for the border on horseback.  Morales and Von Arnheim would be left bound so as to prevent their giving an alarm or offering any interference with the programme.  After the party had been given time to make its way well along toward the border, rebel headquarters was to be notified by radio from the Hampton ranch of the location of the prisoners.  The latter would, therefore, suffer nothing but inconvenience.

“But what fun do I get out of this?” lamented Frank, enviously regarding Bob and Jack.  “You fellows get all the fun and all the glory.  I ride tamely back to the ranch.”

“It is hard luck, Frank,” said Bob.  “But your shoulder is sore and aching from your fight last night, and I’m in better condition to operate the plane.  Besides, you know we can’t take you, as the plane will hold only three and when we get Mr. Hampton we’ll have our full complement.  Some one of us has to stay behind.  You’ve had your share of the fun so far, anyhow, and your turn will come again.”

“I don’t see it,” said Frank.  “It looks to me as if when you rescue Mr. Hampton the fun will all be over.  But that’s the way with you big bullies.  Always picking on the little fellow.”

“Well, you see,” said Bob mischievously, “I’ve got to keep you out of danger for Della’s sake.  Ouch!  Wow!  Letup.  Can’t you take a joke.”

For, lame shoulder notwithstanding, Frank leaped and, bowling the big fellow out of his chair, got astride of his writhing body and began to pummel him.

CHAPTER XXII

FLYING TO THE RESCUE

“Come on.  Strip.”

It was Bob talking, and the command was addressed to Morales and Von Arnheim.  Tom Bodine stood guard over them with leveled revolver.

“But, why?” protested Von Arnheim.

“Ask us no questions an’ we’ll tell you no lies,” said Tom, waving his weapon.  “Jest do what you’re tole.”

Sullenly the two men obeyed.  When their outer clothing had been removed, and they stood revealed in light-weight undergarments—­a well set-up powerful pair of men, about the height of Jack and Bob although neither was so sturdy as the latter—­Bob halted them.