impulse this shape of
mystery and beauty had revealed.

In front of them swept score upon score of her familiars--no longer
dully lustrous, but shining as though cut from blue and polished steel.
They--marched--in ordered rows, globes and cubes and pyramids; moving
sedately now as units.

I looked behind me; out of the spume boiling at the portal, were pouring
forth other scores of the Metal Things, darting through like divers
through a wave. And as they drew into our wake and swam into the light,
their dim lustre vanished like a film; their surfaces grew almost
radiant.

Whence came the light that set them gleaming? Our pace had slackened--I
looked about me. The walls of the cleft or tunnel were perpendicular,
smooth and shining with a cold, metallic, greenish glow.

Between the walls, like rhythmic flashing of fire-flies, pulsed soft and
fugitive glimmerings that carried a sense of the infinitely minute--of
electrons, it came to me, rather than atoms. Their irradiance was
greenish, like the walls; but I was certain that these corpuscles did
not come from them.

They blinked and faded like motes within a shifting sunbeam; or, to use
a more scientific comparison, like colloids within the illuminated field
of the ultramicroscope; and like these latter it was as though the eyes
took in not the minute particles themselves but their movement only.

Save for these gleamings the light of the place, although crepuscular,
was crystalline clear. High above us--five hundred, a thousand feet--the
walls merged into a haze of clouded beryl.

Rock certainly the cliffs were--but rock cut and planed, smoothed and
polished and PLATED!

Yes, that was it--plated. Plated with some metallic substance that was
itself a reservoir of luminosity and from which, it came to me, pulsed
the force that lighted the winking ions. But who could have done such a
thing? For what purpose? How?

And the meticulousness, the perfection of these smoothed cliffs struck
over my nerves as no rasp could, stirring a vague resentment, an
irritated desire for human inharmonies, human disorder.

Absorbed in my examination I had forgotten those who must share with me
my doubts and dangers. I felt a grip on my arm.

"If we get close enough and I can get my feet loose from this damned
thing I'll jump," Drake said.

"What?" I gasped, blankly, startled out of my preoccupation. "Jump
where?"

I followed his pointing finger. We were rapidly closing upon the