ce
its thick sides.

Such immense caves exist in various parts of the world, natural crypts
dating from the geological epoch of the globe. Some are filled by the
sea; others contain entire lakes in their sides. Such is Fingal's Cave,
in the island of Staffa, one of the Hebrides; such are the caves of
Morgat, in the bay of Douarnenez, in Brittany, the caves of Bonifacio,
in Corsica, those of Lyse-Fjord, in Norway; such are the immense Mammoth
caverns in Kentucky, 500 feet in height, and more than twenty miles in
length! In many parts of the globe, nature has excavated these caverns,
and preserved them for the admiration of man.

Did the cavern which the settlers were now exploring extend to the
center of the island? For a quarter of an hour the boat had been
advancing, making detours, indicated to Pencroft by the engineer in
short sentences, when all at once,--

"More to the right!" he commanded.

The boat, altering its course, came up alongside the right wall. The
engineer wished to see if the wire still ran along the side.

The wire was there fastened to the rock.

"Forward!" said Harding.

And the two oars, plunging into the dark waters, urged the boat onwards.

On they went for another quarter of an hour, and a distance of
half-a-mile must have been cleared from the mouth of the cave, when
Harding's voice was again heard.

"Stop!" said he.

The boat stopped, and the colonists perceived a bright light
illuminating the vast cavern, so deeply excavated in the bowels of the
island, of which nothing had ever led them to suspect the existence.

At a height of a hundred feet rose the vaulted roof, supported on basalt
shafts. Irregular arches, strange moldings, appeared on the columns
erected by nature in thousands from the first epochs of the formation of
the globe. The basalt pillars, fitted one into the other, measured
from forty to fifty feet in height, and the water, calm in spite of the
tumult outside, washed their base. The brilliant focus of light, pointed
out by the engineer, touched every point of rocks, and flooded the walls
with light.

By reflection the water reproduced the brilliant sparkles, so that the
boat appeared to be floating between two glittering zones. They could
not be mistaken in the nature of the irradiation thrown from the glowing
nucleus, whose clear rays were shattered by all the angles, all the
projections of the cavern. This light proceeded from an electric source,
and its whit