“I think I see an open place beyond,” remarked Frank, after they had been moving something like two hours after leaving the high plateau.  “And it might be wise while we have the chance to go down and look things over.  Then we will feel fit for another spell of work.”

Accordingly the aeroplane was headed downward.  They circled the opening once or twice in order that the pilot of the aircraft might get his bearings perfectly, and then he headed for the ground.

Even as they were just approaching the earth Frank heard Andy give one of his customary exclamations, such as announced an important discovery.

“Frank, there’s the biplane in the opening!” was what he cried.

Yes, Frank himself had sighted it now, but the discovery came too late to have any effect upon their movements, since they were bound to land, not having room to rise again, even did they wish to do so.

And Frank, as he felt the wheels under the aeroplane touch the earth, also heard a loud cry and some lusty Spanish expletives as a pistol was discharged.

CHAPTER XXIII.

HOMEWARD BOUND—­CONCLUSION.

As was his usual habit, Andy jumped before the monoplane had stopped.  Frank on his part had no sooner seen that everything was going well than he snatched the Marlin rifle from its fastenings.  He realized that they were up against trouble of some sort, for those Spanish exclamations told him there must be one revolutionist at least close by ready to do battle.

“Frank, look out, he’s got a pistol!” cried a voice, which he recognized as belonging to Puss Carberry.

Just then he caught sight of a figure rushing forward.  It was the same man no doubt whom they had seen with Puss in the biplane.  They had evidently broken some important parts in landing and ever since must have been busy trying to mend the same.

“Stop!”

When the advancing revolutionist heard this sharp command and saw that he was being covered by a rifle in the hands of the determined looking pilot of the monoplane, he sized up the situation and then raised his hands in a way that meant he surrendered.

“Drop that gun then!” ordered Frank, and as he did so Puss seized upon it with a snarl of joy.

“Now we’ll see how two can play at that game, you skunk!” gritted the other, as he snapped the pistol straight at the head of the man.

“Here, none of that, Puss.  You leave him to us.  He’s our prisoner, not yours!” ordered Frank, horrified at the rage which the other had shown.

So Puss found that he did not have any authority in the matter, and that if he wanted to get assistance from his old-time rivals in order to finish mending his airship and get away from so dangerous a locality he must do what they said.

He told about how he and Sandy had been out for a trial spin two days before.  That was when Frank and his chum had sighted them from the river.  But that very night some of the revolutionists had made a descent on the home of his uncle, who had a cocoa plantation not many miles away from that of Mendoza, seized him and carried him away, as they also did the little airship.