“This is too slow,” Tom called over his sonarphone. “Let’s try the air dome.”
The dome was a huge underwater bubble of air, created by a repelatron device which actually pushed the ocean water away. The air supply inside was kept pure by one of Tom’s osmotic air conditioners which made use of the oxygen dissolved in the water.
The air bubble, however, even with its jet-propelled platform, also proved inadequate for the research job. Its caterpillar treads repeatedly bogged down in the silt.
“Maybe the seacopter itself is our best bet,” Bud suggested.
“Worth a try,” Tom urged.
But the Sea Hound, too, had a serious drawback. Even with its powerful search beam sweeping the ocean floor as it prowled along, the explorers found their vision too limited.
Finally Tom said, “Bud, we could skin-dive at this depth.”
“Let’s give it a whirl,” Bud urged.
The seacopter surfaced again, while the boys
30 THE ELECTRONIC HYDROLUNG
donned flippers, masks, and air lungs. Then they dropped over the side and made their way slowly downward into the gray-green depths, accustoming themselves gradually to the increased pressure.
“A lot more freedom of action,” Tom thought. “If only we didn’t have to communicate by signals!”
There was a sudden swoosh somewhere on his right. A projectile, Tom realized! Turning, his eyes widened in horror as he saw an uprush of bubbles.
Bud’s air tank had been hit!
CHAPTER III
INVISIBLE SUB
WITHOUT wasting a moment, Tom lunged through the water toward his stricken friend. Bud was floundering and thrashing about weakly. He seemed dazed by the sudden shock of his plight.