"Now we have a demand for more and more oxygen, and we pump it into the vacuum, but eventually we arrive at the point where the pressure of the oxygen inside is greater than the pressure outside. Therefore, the screening force field is broken in its weaker points and the oxygen escapes. When the balance is restored, the rupture isn't sealed and gas seeps in."
Strong glanced questioningly at Captain Howard and at Kit Barnard, who had been asked to remain on Titan and lend his assistance to the problem of the screens.
"Well, gentlemen?" asked Walters, noticing Strong's glance. "That is my theory. Do any of you have a better one? Or a more reasonable explanation?"
Strong, Barnard, and Howard shook their heads. A complete check of every possible source of trouble had been made by the four men and they had found nothing.
"We still have to wait for a report from the electronics sections, sir," said Howard, rubbing his eyes. He started to get up and then suddenly slumped to the floor.
"By the craters of Luna!" cried Walters, jumping to the young officer's side. Howard was picked up and placed on a nearby couch. While Strong and Kit loosened his clothing, Walters grabbed the nearest oxygen mask and slipped it over the spaceman's face.
"Funny that he should pass out like that," commented Strong, sniffing the air. "I still don't smell anything."
Kit looked up at Strong and grinned. "He's not gassed. He's asleep."
"Asleep!" exclaimed Walters.
The enlisted spaceman standing on guard at the door stepped forward and saluted smartly. "Captain Howard hasn't slept for the last five days," he said. "He's been working night and day."