“No, not Rollins,” said Bob, shortly.  It was all right for Jack to shake hands with Muller if he wanted to.  Jack and Muller had been active opponents, and such an act was only sportsmanlike under the circumstances.  But Bob disliked the young German on sight.  “Just let me at the phone,” he said, “and turn on the juice.”

“Very well.”

Muller turned stiffly and entered the power plant adjacent, while Bob in a fever adjusted the headpiece.  As the hum of machinery sounded from the power plant, Jack laid a hand on Bob’s arm.

“Look here, Bob.  Wait a minute.”

Bob regarded him inquiringly, his fingers reaching for the knobs on the instrument box before him, preparatory to sending out his signal call.

“What is it, now?”

“Well, you know old Frank will have his ear glued to the receiver at the cave.  Suppose you call your father, but tell Frank to listen in and not interrupt.”

“Right,” said Bob.  “Well, here goes.”  And he began calling the Hampton ranch.

CHAPTER XXXI

CALM AFTER THE STORM

Meanwhile, as Jack had foreseen, Mr. Temple waited at the radio plant at the Hampton ranch with ill-concealed impatience.

Dave Morningstar, hat pulled down over his eyes, sat in a chair tilted back against the wall, watching him from beneath the brim.  The only signs of life about the ex-cowboy turned mechanic were the occasional movements of the eyes, and the occasional refilling of his pipe, from which lazy streamers of smoke now and again floated upward.

All the evening these two had held watch.  And, as hour after hour passed, with no word from the boys, Mr. Temple’s anxiety rose to a fever.  He condemned himself for ever having given his consent to his son and Jack starting upon so foolhardy an expedition as that of attempting to rescue Jack’s father from the rebel headquarters and fly to safety with him in Bob’s airplane.

Surely, he thought, the boys long since would have reached the ranch and made their departure.  They had promised to call him by radio from the airplane the moment they started on their return flight.  From their failure to do so he argued the worst.  Their expedition must have come to grief, probably even now they were prisoners, perhaps—­

But he shuddered to think of the alternative.  He would not let himself consider that possibility.  In desperation he turned to Dave Morningstar.

“Isn’t there something we can do?” he asked imploringly.

The old ex-cowboy took his pipe from his mouth, spat deliberately to one side, then brought the forelegs of his chair to the floor.

“Le’s see,” he said.  “I been a’most asleep.  Le’s see.  What say to calling the cave?”

Mr. Temple eagerly grasped at the proposal.

“Yes, certainly,” he said.  “Why haven’t I thought of that before?  Perhaps Frank has heard something.”