Within this vapor of light there was no ghost of sound; it was utterly empty of it.

I saw Drake turn to me, his mouth open in a laugh, his lips move in speech--and although he bent close to my ear, I heard nothing.

He frowned, puzzled, and walked on.
Abruptly we stepped into an opening, a pocket of clear air.

Our ears were filled with a high, shrill humming as unpleasantly vibrant as the shriek of a sand blast.

Six feet to our right was the edge of the ledge on which we stood; beyond it was a sheer drop into space.