Tom grinned. “I hope it will. That’s what I intend to find out.”
“How does it work?” Phyl asked, fascinated.
Tom explained, “Actually its function is to replace the carbon dioxide that I exhale with fresh oxygen drawn from the water. Otherwise, although the carbon dioxide I’d breathe out would be a very small amount at a time, it soon would make the air unfit. The nitrogen, which makes up much of the air we breathe, is chemically inert and can be used again and again.”
He pointed to a round screen on one side of the unit. “This is the water intake,” Tom went on, “and this other screen is where the water comes out after we’ve removed its oxygen.”
Near the forward end of the unit, a semirigid
42 THE ELECTRONIC HYDROLUNG
plastic tube was connected, leading up to the face mask. At the rear was a power port for inserting a small solar battery.
“What about this little tuning knob?” Sandy asked.
“That’s the rate control for adjusting the output frequency to the wearer’s breathing rate.” Tom added, “I’ve decided to call the whole apparatus an ‘electronic hydrolung.’”
Chow pushed back his ten-gallon hat and scratched his head dubiously.
“Wai, I’m keepin’ a net handy to drag you out, boss, just in case.”
Tom chuckled and fitted the mask over his face, then made a clean dive into the tank. For the next ten minutes the girls and Chow watched wide-eyed as he swam, walked around, and went through vigorous exercises at the bottom of the tank without once coming up for air.
“Wheel” Sandy exclaimed when Tom finally climbed out. “Make me one, so I can take up skin diving!”