"I hope," said Prester Kleig, "the American flyers in such cases are already dead, for Moyen will be a maniac in his tortures. Munson, do you hurriedly examine the mother-subs and see if you can locate Moyen." * * * * * However, only a scattered aero-sub here and there went down without the strange substance of the yellow ray being released. In most cases, upon the contact of plane with aero-sub, the aero-subs and planes were instantly blotted from view by the yellow, golden flames from the heart of the winged harbingers of Moyen. Golden flames, blinding in their brightness, dropping down, mere shapeless blotches, then fading out to nothingness in a matter of seconds--with aero-sub and airplane totally erased from action and from existence. The American flyers saw and knew now the manner of death they faced. Yet all along the battle front not an American tried to evade the issue and draw out of the fight. A sublime, inspiring exhibition of mass courage which had not been witnessed down the years since that general engagement which men of the time had called the Great War. Prester Kleig turned to look at Maniel. Drops of perspiration bathed the cheeks of the master scientist, but his eyes were glowing like coals of fire. His face was set in a white mask of concentration, and Prester Kleig knew that Maniel would find the answer to the thing he sought if such answer could be found. Would the American flyers be able to hold off the minions of Moyen until Maniel was ready? The fight out there above the waters was a terrible thing, and the Americans fought and died like men inspired, yet inexorably the winged armada of Moyen, preceded by those licking golden tongues, was moving landward. "Great God!" cried Munson. "Look!" * * * * * There was really no need for the order, for every Secret Agent saw as soon as did Munson. Under the sea, just off the coast, the mother-subs had touched their blunt nose against the upward shelving of the sea bottom--had touched bottom, and were slowly but surely following the underwater curve of the land, up toward the surface, like unbelievable antediluvian monsters out of some nightmare. "Yes," said Kleig quietly, "those monsters of Moyen can move on land, and the aero-subs can operate from them as easily on land as under water." Kleig regarded the time, whirled to look at Professor Maniel. One hour and forty minutes had passed since Maniel had begged for two hours in which to prepare some mode of effectively combatting the might of Moyen. Twenty minutes to go; yet the mother-subs would be ashore, dragging their sweating, monstrous sides out of the deep, within ten minutes! Ten minutes ashore and there was no guessing the havoc they could cause to the United Americas! "Hurry, Maniel! Hurry! Hurry!" said Prester Kleig.