And these would be succeeded by soft, flute-like voices, mingling in chorus.
The effect of this, in so dark and dungeon-like a place, where the mighty hand of Nature had performed one of her wildest freaks, was bewildering in the extreme, and gave wing to the strangest fancies.
Hardly a word was spoken; not a brace manned, nor a sheet touched.

The ship moved along as if directed by some unseen hand, for there was no wind in that deep, dark cavern.

Then the water became broken, and the surface checkered with phosphoric lights, flitting and dancing, like so many sprites on a revel.

The arch overhead became covered with a pale light, which seemed to struggle against the darkness; then stars, or what appeared to be stars, were seen, as through a mist.

Then they would suddenly change into every variety of color, and reveal the existence of massive columns of basaltic rock supporting the arch.