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.