reading the expression on his face. She smiled
encouragingly. Then Rawson's hands tightened upon the metal bar. The
man who stood by the central post had moved one lever the merest
trifle. Rawson felt the floor lifting beneath him. Then the shell,
like a bubble of metal, pitched and tossed as the powerful air
currents caught it.

* * * * *

His own lightness saved him from injury. He gripped the bar and held
himself free of the wall. The round top of their strange craft grated
against the domed roof. Then again the ship steadied and seemed
motionless, and Rawson knew they had slipped up into the still air of
that upper shaft.

For one wild instant, filled with impossible hope, Rawson saw this as
a means of ascent to his own world. Then reason tore those wild hopes
to shreds.

"It's closed up above," he thought. "It must be. That's why it sounded
that way. That's why the air drove off through those side passages."

The next instant held no time for thought. Rawson's whole attention
was concentrated upon the bar to which he clung. For, quicker than
thought, the metal shell, the little cylindrical world in which he and
these others were, fell swiftly beneath them.

His body twisted in mid-air. He knew the others were being thrown in
the same manner. Then, what an instant before had been the ceiling was
now a floor beneath his feet, pressing up against him and giving him
weight--and by the whistling rush of the air that tore past their
shell he knew they had fallen with marvelous swiftness straight down
through the throat of that lower shaft.

And now what had been down was up. The ceiling of this strange room
was now their floor, but Rawson was not deceived. "Acceleration," he
said. "It's crowding us. The shell tends to fall faster than we do.
It's like an elevator traveling downward at a swifter rate than a free
falling body."

* * * * *

He had glimpsed the glassy-side of that well into which he knew they
had been flung. He knew that the shrieks that filled the room time and
again were caused by the touching of their shell's guiding and
protecting bars against one glassy wall. Those sounds came always from
the same side and Rawson found momentary satisfaction in his own
understanding of the phenomenon.

"We're falling free," he argued within his own mind, "falling toward
the center of the earth. And a falling body wouldn't follow a vertical
cour