em. The misty atmosphere blurred
outlines slightly, but she could make out the Eastern halves of North
and South America clearly. The Western portions were still in dim
darkness.

"See anything wrong, Miss Kitty?" the lieutenant asked quietly.

She looked more closely, sensing a possible trap in his question, a
revealment of her lack of knowledge.

"I'm not an authority on celestial geography," she said cautiously,
academically. "But obviously the maps I've seen were not accurate in
showing the true continental proportions." She pointed to a small chart
hanging on the side wall. "This map shows Florida, for example, a much
longer peninsula than it actually is. A number of things like that. I
don't see anything else wrong, but, of course, it's not my field of
knowledge."

Lt. Harper looked at her approvingly, the kind of look she gave a bright
pupil who'd been especially discerning.

"Only it's not the map that's wrong, Miss Kitty," he said. "It is _my_
field of knowledge, and I've seen those continental outlines hundreds of
times. They always corresponded to the map ... before."

She looked at him without comprehension.

"Not only that," Sam Eade entered the conversation. "As soon as we were
clear of the wreck, Lt. Harper took a fix on stars and constellations.
He's an astrogator. He knows his business. And they were wrong, too.
Just a little wrong, here and there, but enough. And even more than
that. On a tight beam, I should have been able to make a connection with
Earth headquarters on this set. And I haven't yet got communication, and
we know there's nothing wrong with this set."

"Sam knows his business, too, Miss Kitty," Lt. Harper said. "If he can't
get communication, it's because there isn't any."

She looked wide-eyed from one to the other. For once, she was more
concerned with a problem than with concealing her ignorance about it.

"It means," the lieutenant said, as if he were answering a question she
hadn't yet asked, "that the Earth we are returning to is not the Earth
we left."

"I don't understand," she gasped.

"There's a theory," Lt. Harper answered slowly. "Heretofore it has been
considered only a mathematical abstraction, and having no counterpart in
reality. The theory of multiple dimensions." She looked at him closely,
and in her habitual ambivalence of thought reflected that he sounded
much more intelligent than she had suspected.

"I've read about that," she answered.

He looked