She began to grow pale.
"I'm not a mind-reader," said Calhoun. "But it adds up. You're from Dara. You've been on Weald. It's practically certain that there are other, agents, if you like that word better, on Weald. And there hasn't been a plague on Weald so you people aren't carriers of it. But you knew it in advance, I think. How'd you learn? Did a ship in some sort of trouble land there, on Dara?"
"Y-yes," said the girl. "We wouldn't let it go again. But the people didn't catch—they didn't die—they lived—."
She stopped short.
"It's not fair to trap me!" she cried passionately, "It's not fair!"
"I'll stop," said Calhoun.
He turned to the control-board. The Med Ship was only planetary diameters from Orede, now, and the electron telescope showed shining stars in leisurely motion across its screen. Then a huge, gibbous shining shape appeared, and there were irregular patches of that muddy color which is sea-bottom, and varicolored areas which were plains and forests. Also there were mountains. Calhoun steadied the image and squinted at it.
"The mine," he observed, "was found by members of a hunting-party, killing wild cattle for sport."
Even a small planet has many millions of square miles of surface, and a single human installation on a whole world will not be easy to find by random search. But there were clues to this one. Men hunting for sport would not choose a tropic nor an arctic climate to hunt in. So if they found a mineral deposit, it would have been in a temperate zone. Cattle would not be found deep in a mountainous terrain. The mine would not be on a prairie. The settlement on Orede, then, would be near the edge of mountains, not far from a prairie such as wild cattle would frequent, and it would be in a temperate climate. Forested areas could be ruled out. And there would be a landing-grid. Handling only one ship at a time, it might be a very small grid. It need be only hundreds of yards across and less than half a mile high. But its shadow would be distinctive.