o where an officer stood with what was
apparently a map in his hand. As each searcher saluted and reported,
the officer made a mark on the map. Someone came out from the
cave-mouth next to mine. I fell in behind him.

"No one in cave twenty-one, sir."

"To your post."

The private turned on his heel and marched off to take his place in a
company formation that was rapidly taking shape near by. My turn was
next. What was the number of my cave? A mistake now, and I was
through.

I saluted. "No one in cave twenty, sir."

"To your post."

Had I hit it? When the final check-up came would there be two reports
for one cave, none for another?

A front rank man moved aside. Good: that meant my place was just
behind him. My luck was holding. And never did a man need luck more!

Now was my first chance to look about, to discover what sort of place
this was. It was an oval plain, roughly a mile wide by five miles
long. Buildings, squat structures of corrugated iron, were scattered
here and there. In the distance, to my left, what seemed a great hole
in the ground glowed; a huge disk of light.

Dry land, here, where there should be nothing but a waste of waters!

* * * * *

Puzzled, I strained to see what bordered the plain. It was a tall
cliff, running all around, and towering high in the air. But it wasn't
rock, for it glowed strangely green in the flood of light that
illumined the place. And it was clean cut, rising sheer from the
unevenness of the ground.

Then I remembered. The vertical green wall that soared above me as I
lay dazed from Jim's blow. The translucent green wall in whose depths
I had seen the blind fish rushing toward me. Water! The sea!
Impossible! There were scientific miracle-workers in the enemy's
ranks, but they couldn't have hollowed out a pit such as this in
mid-ocean; forced back the very ocean to create this amphitheatre,
this dry plain on the Atlantic's very bottom: held back the
unthinkable weight of Earth's waters by a nothingness. Incredible!

Yet the accomplished fact stared me in the face.

My eyes traveled up that impossible wall. It must have been at least
six hundred feet high. At its summit, in a murky haze that heaved and
billowed, I made out strange, dim bulks that hung, unsupported. A long
line of them, a long ellipse following closely the curving of the
cliff. Underneath the nearest, barely perceptible, I could make out a
lens-shaped cage of