stness, or strong, decided will; while his
forehead, which is broad, with large bumps over the eyes, shows that
he is a deep thinker. His head is uncovered, for here in this vault
the air is heavy, and his curly black hair is in thick masses, so that
he needs no covering.

What is he doing here?

He drives his boat over the black looking-glass of the lake; round and
round he goes, searching the black walls with anxiety, his lamp raised
in his disengaged hand. Does he imagine that a secret is hidden there?
Does he think that by touching a spring, and saying "Open Sesame," the
treasure hidden there for hundreds of years will spring forth?

In truth, he does find treasures. Here and there from the black
wall--weakly constructed in some places by Nature's hand--a piece of
stone loosens itself--upon it the impression of a leaf belonging to a
long-ago-extinct species. A wonderful treasure this! In other places
he comes upon unknown crystals, to which science has not as yet given
a name; or upon a new conglomeration of different quartz, metal, and
stone--a silent testimony to a convulsion of Nature before this world
was. All these witnesses speak.

The pillars, too; over them the water of the pond has by degrees
formed a crustation of crystals, small, but visible even without a
glass. This, too, gives testimony.

The pond is in itself wonderful. It has ebb and flow: twice in the day
it empties itself; twice in the day it fills. The water rushes in
leaps and bounds, joyously, tumultuously, into this dark, sullen
vault; fills it higher, higher, until it reaches the point on the
pillars where the color changes. There it remains, sometimes for two
hours, stationary, smooth, and placid as a glass. Then it begins to
sink, slowly, surely, until it vanishes away into the secret
hiding-places from whence it has come. Curious, mysterious visitor!
The man in the boat knows its ways; he has studied them. He waits
patiently, until, with a sullen, gurgling sound, as if lamenting the
necessity, the last current of water vanishes behind a projecting mass
of coal. Then he hurriedly casts off his coat, his shoes, his
stockings; he has nothing on but his shirt and trousers. He fastens
round him a leather pocket, in which is a hammer and chisel; he takes
his safety-lamp and fastens it to his belt; and, so equipped, he
glides into one of the fissures in the black rock. He is following the
vanishing stream. He is a courageous man to undertake