The members of the conference followed Hero Giles down a short corridor, through a couple of doors and into a chamber where a huge disc of crystal stood on edge fixed upon an axis above a bewildering array of wires, pipes and gauges. * * * * * Hero John, who seemed familiar with the mechanism, turned a lever, whereupon the disc commenced to spin like a pie plate on a dance floor. Faster and faster it spun, silently gathering speed each second while a low humming sound filled the chamber. Gradually the outline of the whirling disk commenced to brighten, tinting the scar-seamed, craggy features of the Atlantean generals and picking glorious, glowing lights from the jewels on Hero Giles' wonderfully engraved breastplate. "Ah." Hero John turned a small dial. "The crystal warms. Look, oh Wanderers!" Nelson rubbed his eyes incredulously, for in the heart of the shimmering circle had materialized the outline of a room with walls of yellow marble. "Well, I'm damned!" gasped Alden. "See how it flickers!" As the revolving disc of crystal gained top speed, the flickering subsided and a picture, clearer than most photographs, could be seen in the center. A wondrously slender, yellow-haired young girl clad in Grecian robes of pale blue sat in deep despond upon a plain wooden couch, with a black haired servant kneeling before her, apparently lacing sandals on her tiny, pink-hued feet. "Bring closer the face," snapped Hero Giles gruffly. Gradually the focus changed, like the close-up of a movie camera, until in the center of the madly whirling disc could be seen in minute detail and living color the face of an indescribably lovely girl. "Whew," muttered Nelson, staring in silent amazement. "No wonder they want her back! She makes Ziegfeld's little girls look like Armenian refugees." He cast a sidewise glance, but Alden had apparently not heard him; the younger American stood gazing with rapturous joy at the girl. "Aye! Aye!" The two veteran generals uttered stifled groans and one of them drew a hand across his eyes. "Poseidon save her! Aye! Preserve the fair Altara." "Wouldst thou not doubly save her, now?" demanded Hero John in a low voice that bespoke his anguish. He seemed suddenly older than the grim, helmeted veterans to either side. "You bet! I guess a man sees a face like that only once is a lifetime. And now," Nelson continued with an effort to return to the practical, "there's no time to be lost--so I'd just like to take a look at those pteranodons of yours." * * * * * A few minutes later, the two aviators found themselves nearing a lofty structure which adjoined the imperial palace. It was constructed along the lines of an immense aviary. Between beautiful, glistening Ionic columns of white marble, gleamed bronze bars, set at regular intervals to prevent the escape of the most appalling creatures which could ever have skimmed the air.