"Thionite!" he explained to her, bitterly. "I never saw a man take thionite before, let alone die of it, but it's the only thing I can think of that can turn a man into such an utter maniac as that one was. They're growing the stuff. They must be a zwilnik outfit from top to bottom. That's why they've got to rub us out."
"But how could it get out?"
"Through a fault, Fairchild said, a crack in the rocks. A millionth of a gram is enough, you know, and the stuff's so fine that it's terrifically hard to hold. If we could only tell the Patrol!"
But they could not tell, nor could they escape. They exerted their every resource, exhausted every possibility—in vain. And as day followed day Ryder almost went mad under the grinding thought that they both must die without any opportunity of revealing their all-important knowledge. Hence he burst out violently when the death-cell's speaker gave tongue.
"Eureka? Damn your gloating soul to hell, Graves!" he yelled furiously.
"This isn't Graves!" the speaker snapped. "Cloud. Storm Cloud, the Vortex Blaster, investigating—"
"Oh, Bob, it is! I recognize his voice!" the girl screamed.
"Quiet! This is a zwilnik outfit, isn't it?"
"I'll say it is," Ryder gasped in relief. "Thionite—"
"That's enough, details later. Keep still a minute!" Locked together in almost overpowering relief, the imprisoned pair listened as the crisp voice went on: