ater instead of being plunged in utter
darkness? The vast landscape before me was lit up like day. But there
was wanting the dazzling brilliancy, the splendid irradiation of the
sun; the pale cold illumination of the moon; the brightness of the
stars. The illuminating power in this subterranean region, from its
trembling and Rickering character, its clear dry whiteness, the very
slight elevation of its temperature, its great superiority to that of
the moon, was evidently electric; something in the nature of the aurora
borealis, only that its phenomena were constant, and able to light up
the whole of the ocean cavern.

The tremendous vault above our heads, the sky, so to speak, appeared to
be composed of a conglomeration of nebulous vapors, in constant motion.
I should originally have supposed that, under such an atmospheric
pressure as must exist in that place, the evaporation of water could not
really take place, and yet from the action of some physical law, which
escaped my memory, there were heavy and dense clouds rolling along that
mighty vault, partially concealing the roof. Electric currents produced
astonishing play of light and shade in the distance, especially around
the heavier clouds. Deep shadows were cast beneath, and then suddenly,
between two clouds, there would come a ray of unusual beauty, and
remarkable intensity. And yet it was not like the sun, for it gave no
heat.

The effect was sad and excruciatingly melancholy. Instead of a noble
firmament of blue, studded with stars, there was above me a heavy roof
of granite, which seemed to crush me.

Gazing around, I began to think of the theory of the English captain who
compared the earth to a vast hollow sphere in the interior of which the
air is retained in a luminous state by means of atmospheric pressure,
while two stars, Pluto and Proserpine, circled there in their mysterious
orbits. After all, suppose the old fellow was right!

In truth, we were imprisoned--bound as it were, in a vast excavation.
Its width it was impossible to make out; the shore, on either hand,
widening rapidly until lost to sight; while its length was equally
uncertain. A haze on the distant horizon bounded our view. As to its
height, we could see that it must be many miles to the roof. Looking
upward, it was impossible to discover where the stupendous roof began.
The lowest of the clouds must have been floating at an elevation of two
thousand yards, a height greater than that