Free Tom Swift and His Spectromarine Selector by Victor Appleton II

visit the two rescued crewmen in sickbay, who were resting in cots under the watchful eye of Doc Simpson.
    "We surely owe our lives to you and your companions," murmured Professor Belam Centas, his accent showing his Spanish-French origins. He was a wiry man of late middle age, his hair thick and iron-gray, his skin very pale. "My dear Hydra-Gaea decided to betray me."
    "We can discuss that later, sir, after you’ve rested."
    The researcher nodded weakly. "Your Navy man has spoken to us. It seems it would be easier in many ways if we remained with your expedition until the completion of your remarkable project, which he described to us. A matter of secrecy, we were told. All very exciting, and we have no objection, if you will kindly inform the Foundation, in France, of these matters."
    Tom promised to do so and turned to the other man, stocky and black-haired. He spoke with difficulty, evidently little tutored in the English language. "I am Mordo, his assistant and student. I must thank you also, Mr. Swift."
    Tom, Bud, and their two assistants, Nina Kimberley and Mel Flagler, all clad in Fat Man suits, exited the mantacopter. They proceeded to set up the osmotic air conditioner machinery on the outskirts of the city. This device would draw dissolved oxygen and nitrogen from the sea water to provide an atmosphere for the air bubble.
    When they returned to the Supermanta, the repelatron was standing ready for action in the open airlock. It consisted of a large metal sphere, some five feet in diameter, mounted on a thick platform, together with a console and electronic control panel. The sphere functioned as the radiator-antenna which beamed out repulsion rays in all directions. During the mission it would be connected by thick cables to the mantacopter’s atomic power plant.
    "Okay, folks, let’s slide it out to the anchor point," Tom directed. Reaching a spot on the rise, the repelatron was set down and long anchor-screws drilled themselves into the solid rock beneath.
    Tom adjusted several tuning knobs, then gripped the repelatron control lever, ready to switch on power.
    "Ay-Oke, genius boy?" commed Bud.
    "Here we go!"
    Tom threw the master control switch, and a balloon of air began to form in the water around the radiator sphere. After checking the readouts, the mission leader increased the power, manipulating the dials with the fingers of the Fat Man’s robotic arms.
    "Thar she blows!" Bud grinned with excitement as the giant bubble of air expanded with a leap in all directions. Its inner air, temporarily at very low pressure, was being released from tanks in the repelatron’s platform.
    Steadily the repelling waves forced back the sea water on all sides. The bubble grew bigger and bigger until it took in the Supermanta stem to stern and continued outward and upward to the canyon wall. As the other craft maneuvered away, the airspace swelled still more, becoming a domelike hemisphere as its lower reaches effortlessly penetrated the ground. When the bubble reached the point where the osmotic air conditioner had been set up, Tom sent a remote-control signal from his Fat Man. Instantly the machine thrummed into action, spreading a pleasant, less humid atmosphere through the bubble. A green signal light flashed as normal air pressure was reached.
    Tom opened his hatch and climbed out of the Fat Man and took a deep breath. "We’re in business, fellows!" he announced, grinning. The air bubble now extended to a radius of one thousand feet, its limit. For the first time in millennia, blocks of the city of gold waited in eerie silence in the open air!
    "Okay if the rest of us get out too?" asked Nina through her suit’s external speaker.
    "I’m afraid not," was the apologetic response. "I just got out to give the air the old lung test. We need to help set up the other repelatrons."
    Even the large-size repelatron was not powerful enough to establish an airspace over the entire site, which was much larger than Enterprises’