“But what are we going to do?” Estelle tearfully insisted.

“We’re going to muddle along as well as we can,” answered Arthur cheerfully, “until we can get back to where we started from.  Maybe the people back in the twentieth century can send a relief party after us.  When the skyscraper vanished it must have left a hole of some sort, and it may be possible for them to follow us down.”

“If that’s so,” said Estelle quickly, “why can’t we climb up it without waiting for them to come after us?”

Arthur scratched his head.  He looked across the clearing at the skyscraper.  It seemed to rest very solidly on the ground.  He looked up.  The sky seemed normal.

“To tell the truth,” he admitted, “there doesn’t seem to be any hole.  I said that more to cheer you up than anything else.”

Estelle clenched her hands tightly and took a grip on herself.

“Just tell me the truth,” she said quietly.  “I was rather foolish, but tell me what you honestly think.”

Arthur eyed her keenly.

“In that case,” he said reluctantly, “I’ll admit we’re in a pretty bad fix.  I don’t know what has happened, how it happened, or anything about it.  I’m just going to keep on going until I see a way clear to get out of this mess.  There are two thousand of us people, more or less, and among all of us we must be able to find a way out.”

Estelle had turned very pale.

“We’re in no great danger from Indians,” went on Arthur thoughtfully, “or from anything else that I know of—­except one thing.”

“What is that?” asked Estelle quickly.

Arthur shook his head and led her back toward the skyscraper, which was now thronged with the people from all the floors who had come down to the ground and were standing excitedly about the concourse asking each other what had happened.

Arthur led Estelle to one of the corners.

“Wait for me here,” he ordered.  “I’m going to talk to this crowd.”

He pushed his way through until he could reach the confectionery and news-stand in the main hallway.  Here he climbed up on the counter and shouted: 

“People, listen to me!  I’m going to tell you what’s happened!”

In an instant there was dead silence.  He found himself the center of a sea of white faces, every one contorted with fear and anxiety.

“To begin with,” he said confidently, “there’s nothing to be afraid of.  We’re going to get back to where we started from!  I don’t know how, yet, but we’ll do it.  Don’t get frightened.  Now I’ll tell you what’s happened.”

He rapidly sketched out for them, in words as simple as he could make them, his theory that a flaw in the rock on which the foundations rested had developed and let the skyscraper sink, not downward, but into the Fourth Dimension.

“I’m an engineer,” he finished.  “What nature can do, we can imitate.  Nature let us into this hole.  We’ll climb out.  In the mean time, matters are serious.  We needn’t be afraid of not getting back.  We’ll do that.  What we’ve got to fight is—­starvation!”