"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.

Threatened with dire things if he refused to obey, he had been compelled to go up in company with the man who was now their prisoner, a Spaniard, who had once sailed in a balloon and knew something about that type of aviation, though having much to learn in connection with modern aeroplanes.

Sighting our two Bird boys, of course Puss had known who they were. But the man was positive that they must be spies sent out by the government to learn what the revolutionists might be doing up the Magdalena. And he had threatened all sorts of things, Puss declared, unless a hot pursuit were carried on. Secretly Frank was of the opinion that it would require very little urging to make Puss Carberry do his level best to overtake any aerial craft piloted by one Frank Bird, toward whom he had always felt the most bitter animosity.

After about an hour's hard work Frank managed to get the biplane in decent trim for a flight. He was also able to spare the other some gasoline.

Had he been allowed to have his own way Puss would have left the Spaniard in the forest, where he might have died, being unable to make his way to civilization. But Frank would not hear of it. He obtained a solemn promise from the man that he would not make any further effort to obtain control of the biplane, and then Puss was made to take him aboard. Of course, Frank had made sure that the man carried no weapon and that his revolver was thrown away.

They left the glade in the forest soon after the biplane had started. Puss managed to keep close to the others while they headed off toward the northeast. He did not wholly trust the passenger he was carrying and wanted to remain within call of the three who relied upon the monoplane to carry them to safety.

They could even shout out to each other as they sailed along. Thus Puss warned them when they were approaching a camp of the revolutionists as they drew near the region of the river, and they were able to change their course, not wishing to again run the perilous gantlet of gun-fire.

When another descent was deemed necessary it was close to the Magdalena, though many miles south of the town where the cocoa planters lived.