“Let’s go over Amy-Ran,” Bob proposed.

“Right-O.”

The course was quickly calculated and the plane’s nose pointed in the direction of the ancient fastness which was still the property of the descendants of the famous Yncas, whose people had once inhabited the vast empire which was the world’s most civilized and prosperous government. Jim increased the speed and the plane roared through the sky above the magnificent Andes Mountains with their numberless spurs and beautiful valleys, which looked as if only the greatest of nature’s artists had been entrusted to shape their perfect outline. Here and there were high plains whose smooth surfaces looked as if they were set with glistening opals, while others were dark-wooded with forests which were broken only by lovely lakes of crystal-clear water that reflected the sky above them like wonderful mirrors. The sun, rising with a splendid burst of brilliance, sent its rays flashing until every inch they touched leaped to life and color.

The Flying Buddies took in all of the marvelous scenes rolling beneath them, and were intensely sorry for grounded chaps who had never experienced the thrill of viewing such a panorama to the accompaniment of wind singing through the wires of an airplane carrying them swiftly through space between the earth and sky. Finally, in the distance, they made out the S-shaped plateau of Amy-Ran, whose edge was rimmed like a crown with the giant stone that had once formed a section of its inaccessible fortress.

In a few minutes the “Lark” was circling like a bird above one end and as Jim calculated his landing he recalled the day Carlos de Castro had brought them to the spot, the day that young Arthur Gordon had so mysteriously appeared and assaulted them. There had been no means of escape from the precipitous rock or the murderous attack of the Texas outlaw and Austin had been sure that it was only a matter of minutes before their three lifeless bodies would be pounced upon by hungry vultures whose nests were secreted on nearby crags. When his Buddies lay helpless, Jim was standing before a black-nosed revolver but before its trigger could be pressed Yncicea Haurea and his uncle Corso stepped into the ruin and the tide of battle was swiftly and effectively turned. The motor was silenced and the “Lark” was gliding quietly down.

“I’m taking her where she can be a bit out of sight.”

“Great brain work. Never know who may take the air with a view to doing scout work. Peaceful spot, this old Peru, when there is no one about,” said Bob. He too had been thinking of the wild experiences they had been through, but his thoughts had been on the more recent happenings, and as they made the descent his eyes lingered with amusement at the nearby peak which a few nights before had given a perfect imitation of a seething volcano with tons of burning lava rushing threateningly on Gordon and his gang. If it had been the real thing, the Flying Buddies and the two De Castros would have been buried under many feet of molten rock and cinders. But as a piece of clever stage business it had struck terror into the hearts of the man with the green mask and his companions. In their mad rush to get above the danger zone several of them had been killed.

“Give a calf enough rope and he’ll hang himself,” Caldwell remarked as the plane’s wheels touched the chosen landing spot and rolled a few feet. “Queer how many of those guys have eliminated themselves in one way or another.”

“Yes. I should think they’d begin to tumble to themselves that they are amateurs and quit trying to get the better of the men they are so intent on robbing,” Jim answered. The plane rolled beneath the shelter of the fortress wall and when she was in a position where she could not be seen by curious flyers, he brought her to a stop. “I have a hunch that some bright lad in that gang may come flying about to have a look at the remains of the volcano.”

“Well, won’t he get the jolt of his gay careless youth when he can’t find a crater as big as a hole in a tooth?” chuckled Bob. “Any hunches that we’ll find a Lab. man around?”