,
and fairer in colour than our highly-valued emeralds and sardonyxes and
jaspers, and other gems, which are but minute fragments of them: for
there all the stones are like our precious stones, and fairer still
(compare Republic). The reason is, that they are pure, and not, like
our precious stones, infected or corroded by the corrupt briny elements
which coagulate among us, and which breed foulness and disease both in
earth and stones, as well as in animals and plants. They are the jewels
of the upper earth, which also shines with gold and silver and the like,
and they are set in the light of day and are large and abundant and in
all places, making the earth a sight to gladden the beholder's eye.
And there are animals and men, some in a middle region, others dwelling
about the air as we dwell about the sea; others in islands which the air
flows round, near the continent: and in a word, the air is used by them
as the water and the sea are by us, and the ether is to them what the
air is to us. Moreover, the temperament of their seasons is such that
they have no disease, and live much longer than we do, and have
sight and hearing and smell, and all the other senses, in far greater
perfection, in the same proportion that air is purer than water or the
ether than air. Also they have temples and sacred places in which the
gods really dwell, and they hear their voices and receive their answers,
and are conscious of them and hold converse with them, and they see the
sun, moon, and stars as they truly are, and their other blessedness is
of a piece with this.

Such is the nature of the whole earth, and of the things which are
around the earth; and there are divers regions in the hollows on the
face of the globe everywhere, some of them deeper and more extended than
that which we inhabit, others deeper but with a narrower opening
than ours, and some are shallower and also wider. All have numerous
perforations, and there are passages broad and narrow in the interior of
the earth, connecting them with one another; and there flows out of and
into them, as into basins, a vast tide of water, and huge subterranean
streams of perennial rivers, and springs hot and cold, and a great fire,
and great rivers of fire, and streams of liquid mud, thin or thick (like
the rivers of mud in Sicily, and the lava streams which follow them),
and the regions about which they happen to flow are filled up with them.
And there is a swinging or see-saw in