"Eight days," she said in a hoarse whisper.
He nodded solemnly. "Every hour means they must be coming closer and closer. Every lonely hour means that it can't be many more, because they've covered all the places where we weren't. Follow me, Alice?"
She shook her head unhappily.
Doggedly he tried to explain. "They know that we must lie within a certain truncated conical volume of space. They comb this space bit by bit and chart it. Since the volume is known, and since it takes so many hours of work to comb a given volume, that means that at the end of a given time all the predicted volume of space has been covered. Since we must lie within that, we are bound to be picked up before they cover the last cubic mile."
"But how long?" she breathed.
"I wouldn't know," he told her honestly. "I have no possible way of computing it. They've got the best of computers and plotters, and they've got the law of probabilities on their side. But it's dead certain we'll be found."
"I hope."
"I know," he said.
"You've changed, Jock Norton."
"Changed?"