Baker shook his head, smiling gently. "Not really masks, my friend. They cover only the end of your nose. They're marvelously comfortable, as you'll soon see. In a few days you won't even be aware you're wearing them."
"Like hell," Brace growled. "I'll know I'm wearing it."
Baker shrugged affably, and then gestured invitingly to the long, thin, somber looking man who stood with his hand up, not far from Brace. This was Lurie, the biology professor, a nice, harmless Ph.D.
"What's wrong with the atmosphere?" Lurie said. "Why is an artificial supply of oxygen necessary?"
"The answer is very simple," Baker said. "This is a young planet, as planets go. The conditions here are just about what they were on Earth eons ago. The carbon dioxide exhaled from the interior of the planet and saturating the atmosphere is gradually being converted by the plant life—broken down, I should say, releasing free oxygen. At the present time, our oxygen content is about seven percent. Eventually, the oxygen will probably reach the level you find on the surface of the Earth—about twenty-one percent. But that should take a long time; I'm afraid none of us will be around when that point is reached. Meanwhile, our plants luxuriate in an atmosphere rich in carbon dioxide. Plants, as you know, use carbon dioxide for their most essential life process—photosynthesis. But I'm sure Professor Lurie can tell you much more about that than I can."
Lurie blinked embarrassedly, and looked aside at his wife, and smiled shyly.
"Mr. Baker!" another voice broke in.
This speaker, Baker recognized, was Harvey Flanders, definitely a dangerous type. He was a brooder; he had a slow, relentless fire in his eyes. Baker had been doubtful about him from the start; he'd had half a mind to reject his application. But as things happened, the passenger list was one couple short and so, at the last moment, he had taken Flanders and his wife. Was he going to have reason to regret what he'd done?
"How do you propose to make up for this fraud you've put over on us?" Flanders was saying.
"I'm sorry," Baker said. "Did you say fraud?"