Bob started forward to help Jack.  The latter, however, took one look at the sentries and then dashed into the left wing of the building.

The sentries for a moment did not pursue, believing the fleeing man was Morales.  Instead, they bent above Muller and helped him to his feet.  Bob halted, and backed into the bushes, keeping his eyes on the scene.  No use rushing in to help Jack now.  He would merely succeed in getting into trouble himself, without aiding his chum.

From his vantage point he was able to read aright what followed.  Although he could not overhear what was being said and would not have understood the Spanish words, if he had overheard, nevertheless he gathered that Muller was explaining the fugitive was not Morales, but someone wearing his clothes.

Then he saw the sentries dart away in pursuit of Jack, while Muller whipped out a revolver and fired three shots into the air.

“That’s an alarm,” Bob said to himself.  “I’d better back off before this place is alive with soldiers.”

Turning, he ran through the trees.  Big Bob was not the one to desert a friend, but he saw no chance to help Jack now.  On the other hand, he told himself, if he retained his freedom, he would be able to help Jack later perhaps.

Suddenly he carromed into a man running toward the house.  Both rebounded from the contact.  Bob saw the other was a Mexican with a rifle.  Quick as thought, he lashed out with his right fist and caught the soldier on the point of the jaw.  Totally unprepared for this attack, the man went down as if shot.

Bob ran on at redoubled speed, burst through the screen of trees, and dashed across the landing field toward his airplane.  He had no definite idea as to what course to pursue.  He and Jack, of course, had counted upon the possibility of Jack’s being discovered.  In that case, when he heard the alarm, Bob—­supposedly sticking by his airplane—­was to have flown away.

There were shouts behind him.  Evidently his soldier victim had recovered.  Perhaps, even, Muller had suspected the truth, namely, that if Jack were not Morales the aviator who had brought him was not Von Arnheim.  In that case, Muller would be on his trail and he would have no time to lose.

What should he do?

The shouts behind him were not repeated.  Perhaps, after all, his identity was not yet suspected and he was not pursued.  Jack might be keeping all hands busy at the ranch.

In great leaps, he approached the airplane and, as he drew near, another thought obtruded itself.  If he were to take flight in it, how was he to get away?  Who would crank the motor by twirling the propeller?

This latter difficulty was quickly solved.  Two Mexicans stood at respectful attention as he approached.  Bob was dismayed for a moment, but then, seeing their awkward salute, he chuckled inwardly.  They mistook him for Von Arnheim and evidently that German officer was a martinet who exacted a measure of discipline from the slovenly rebel soldiers.