"I've just thought of that," said Cavor. "That's what I meant when I said

the thing is finished. The inner glass sphere can be air-tight, and,

except for the manhole, continuous, and the steel sphere can be made in

sections, each section capable of rolling up after the fashion of a roller

blind. These can easily be worked by springs, and released and checked by

electricity conveyed by platinum wires fused through the glass. All that

is merely a question of detail. So you see, that except for the thickness

of the blind rollers, the Cavorite exterior of the sphere will consist of

windows or blinds, whichever you like to call them. Well, when all these

windows or blinds are shut, no light, no heat, no gravitation, no radiant

energy of any sort will get at the inside of the sphere, it will fly on

through space in a straight line, as you say. But open a window, imagine

one of the windows open. Then at once any heavy body that chances to be in

that direction will attract us--"

I sat taking it in.

You see?" he said.

Oh, I see."

Practically we shall be able to tack about in space just as we wish. Get

attracted by this and that."

"Oh, yes. That's clear enough. Only--"

The First Men In The Moon