of sight—a peculiarity sometimes met with in
the inhabitants of subterranean waters.

During their passage, they nearly caught a
tartar, in the shape of a living ichthyosaurus,
an antediluvian monster with the snout of a
porpoise, the head of a lizard, and the teeth of
a crocodile. Luckily, its attention was diverted
from the raft by the appearance of its sworn
enemy, a plesiosaurus—a serpent thirty feet
long, with a tortoise's shell forty feet wide, and
great goggle eyes as big as your head. This
pretty pair, closing with admirable pluck,
fought an unrecorded number of rounds for a
couple of hours. At last, by a clever dodge,
the ichthyosaurus gave the decisive blow, and
left his adversary for dead.

After this episode, the raft was. assailed by a
storm, which drove them back to a point near
their starting-place. On landing, they were
startled by finding on the sand—not, like Robinson
Crusoe, a footprint—but a dagger of the
sixteenth century. A human visitor had, therefore,
preceded them. But who? A rock close
by, carved with the Runic letters A. S., proved
that it must have been Arne Saknussem
himself. Onward, then, to follow his steps! How
did he get away from the Subterranean Sea?
Evidently, down this gallery, which is closed
by a fallen mass of rock. The rock must be
blown up by gun-cotton.

When all was ready to spring the mine, the
adventurous three set light to the match, and then,
retreating to their raft, pushed out from shore
to a prudent distance. The match had been
calculated to burn ten minutes. The Professor,
chronometer in hand, anxiously awaited the
result of the explosion. "Five minutes more,"
he said, "and then!—Four minutes!—Three!
—Two!—In one minute——"

Whether their ears heard the explosion, the
travellers could never remember. The form of
the surrounding rocks suddenly changed. They
opened like a curtain, and displayed a yawning
abyss, dark, fathomless, into which the sea
poured, like a monster Niagara, carrying with
it the raft and its burden. In less than a
second, light gave place to utter darkness.
The travellers clung together in despair. For
hours they were carried down by the torrent,
with a speed to which the swiftest railway
rates are sluggishness. They turned their
backs to the air through which they rushed, to
avoid being suffocated. They glided no more;
they fell, with still increasing velocity.
Suddenly, after an interval of time which they
could not estimate, they felt a sort of shock.
The raft, without meeting any solid obstacle,
was suddenly arrested in its course. An
immense sheet of water drenched its surface.
The explorers were choked—all but drowned.
Nevertheless, the inundation did not last.
Their lungs again breathed the air freely. They
held together bravely; the raft still carried all
the three—and they had reached the centre of
the globe! How they got back (for they did get
back) to the surface, the reader will learn by
perusing M. Jules Verne's Voyage au Centre de
la Terre: of whose scenery, spirit, and science,
this slight summary gives but a faint idea.

For a less flighty excursion into the interior
we must gain the foot of Mont Cenis, where
men are boldly grappling with one horn of an
awkward dilemma. The railway is complete from
Paris to Turin, except over Mont Cenis, which
is still traversed by horse-power instead of
steam.

But the piercing of Mont Cenis by a tunnel
presents simply a choice between two difficulties.
By taking the high and circuitous line, the railway
would have to mount to the region of snowstorms
and avalanches. During a great part of
the year it would be dangerous and impracticable,
unless protected by a covered gallery, the
expense of which would be very great. Such a
railway, with such a gallery, though more quickly
executed than a tunnel, would stand in need of
constant repair, and with every precaution must
at times be unsafe. On the other hand, a
tunnel once bored through a mountain of rock,
would last for ever. It was resolved to undertake
the tunnel.

But the tunnel of Mont Cenis, or rather of
the Col de Fréjus (for, if the road passes over
the Col of Mont Cenis, the railway will pass
under the Col of Fréjus), offered special difficulties:
Most tunnels can be attacked at several
points of their course at once, by sinking wells
or galleries, which serve both for ventilation and
the extraction of excavated material. When
the fragments of the tunnel are all joined, the
whole is finished. But in piercing such a mass
as Mont Cenis, wells or slanting galleries were
next to impossible. The tunnel could be begun
at two places only, namely, at each end: and
the further it advances, the greater is the difficulty
of introducing fresh air and extracting the
rubbish. New methods of piercing the rock
and of ventilation had to be invented.
Its projectors might well have been excused for
renouncing the accomplishment of a subterranean
gallery twelve thousand metres, or seven miles
and a half, in length.

Attempts were made to do without powder
for blasting the rock, in order to avoid the
vitiation of the air consequent on explosions.
Boring the rock by steam power was proposed;
but the steam-engine also consumes oxygen. It
ended in using sportsmen's instead of miners'
gunpowder, and by boring the blast-holes with
a machine set in motion by air compressed with
the force of six atmospheres. The air is
compressed by pumps worked by the waterfalls, of
which there is no scant. Gas-lamps have been
substituted with advantage for oil-lamps; gun-
cotton has been thought of to replace
gunpowder; and sucking-pumps to draw out the
foul air through long tubes.

The extraction of the rubbish is very slow
work. At the distance of from a thousand to
fifteen hundred metres from the mouth of the
tunnel, it requires about six hours, including in
that period aoout two hours for firing the mines;
which time will increase as the distance
increases. The boring of the holes is performed