The Mysterious Island (22 page)

Under the engineer's directions, Pencroft, armed with a pickaxe, which
he handled skillfully and vigorously, attacked the granite. The hole was
made on the point of the shore, slanting, so that it should meet a
much lower level than that of the water of the lake. In this way the
explosive force, by scattering the rock, would open a large place for
the water to rush out.

The work took some time, for the engineer, wishing to produce a great
effect, intended to devote not less than seven quarts of nitro-glycerine
to the operation. But Pencroft, relieved by Neb, did so well, that
towards four o'clock in the evening, the mine was finished.

Now the question of setting fire to the explosive substance was raised.
Generally, nitro-glycerine is ignited by caps of fulminate, which in
bursting cause the explosion. A shock is therefore needed to produce
the explosion, for, simply lighted, this substance would burn without
exploding.

Cyrus Harding could certainly have fabricated a percussion cap. In
default of fulminate, he could easily obtain a substance similar to
guncotton, since he had azotic acid at his disposal. This substance,
pressed in a cartridge, and introduced among the nitro-glycerine, would
burst by means of a fuse, and cause the explosion.

But Cyrus Harding knew that nitro-glycerine would explode by a shock.
He resolved to employ this means, and try another way, if this did not
succeed.

In fact, the blow of a hammer on a few drops of nitro-glycerine, spread
out on a hard surface, was enough to create an explosion. But the
operator could not be there to give the blow, without becoming a victim
to the operation. Harding, therefore, thought of suspending a mass of
iron, weighing several pounds, by means of a fiber, to an upright just
above the mine. Another long fiber, previously impregnated with sulphur,
was attached to the middle of the first, by one end, while the other lay
on the ground several feet distant from the mine. The second fiber being
set on fire, it would burn till it reached the first. This catching
fire in its turn, would break, and the mass of iron would fall on the
nitro-glycerine. This apparatus being then arranged, the engineer, after
having sent his companions to a distance, filled the hole, so that the
nitro-glycerine was on a level with the opening; then he threw a few
drops of it on the surface of the rock, above which the mass of iron was
already suspended.

This done, Harding lit the end of the sulphured fiber, and leaving the
place, he returned with his companions to the Chimneys.

The fiber was intended to burn five and twenty minutes, and, in fact,
five and twenty minutes afterwards a most tremendous explosion was
heard. The island appeared to tremble to its very foundation. Stones
were projected in the air as if by the eruption of a volcano. The shock
produced by the displacing of the air was such, that the rocks of the
Chimneys shook. The settlers, although they were more than two miles
from the mine, were thrown on the ground.

They rose, climbed the plateau, and ran towards the place where the bank
of the lake must have been shattered by the explosion.

A cheer escaped them! A large rent was seen in the granite! A rapid
stream of water rushed foaming across the plateau and dashed down a
height of three hundred feet on to the beach!

Cyrus Harding's project had succeeded, but, according to his usual
habit he showed no satisfaction; with closed lips and a fixed look, he
remained motionless. Herbert was in ecstasies, Neb bounded with joy,
Pencroft nodded his great head, murmuring these words,—

"Come, our engineer gets on capitally!"

The nitro-glycerine had indeed acted powerfully. The opening which it
had made was so large that the volume of water which escaped through
this new outlet was at least treble that which before passed through the
old one. The result was, that a short time after the operation the level
of the lake would be lowered two feet, or more.

The settlers went to the Chimneys to take some pickaxes, iron-tipped
spears, string made of fibers, flint and steel; they then returned to
the plateau, Top accompanying them.

On the way the sailor could not help saying to the engineer,—

"Don't you think, captain, that by means of that charming liquid you
have made, one could blow up the whole of our island?"

"Without any doubt, the island, continents, and the world itself,"
replied the engineer. "It is only a question of quantity."

"Then could you not use this nitro-glycerine for loading firearms?"
asked the sailor.

"No, Pencroft; for it is too explosive a substance. But it would be easy
to make some guncotton, or even ordinary powder, as we have azotic acid,
saltpeter, sulphur, and coal. Unhappily, it is the guns which we have
not got.

"Oh, captain," replied the sailor, "with a little determination—"

Pencroft had erased the word "impossible" from the dictionary of Lincoln
Island.

The settlers, having arrived at Prospect Heights, went immediately
towards that point of the lake near which was the old opening now
uncovered. This outlet had now become practicable, since the water no
longer rushed through it, and it would doubtless be easy to explore the
interior.

In a few minutes the settlers had reached the lower point of the lake,
and a glance showed them that the object had been attained.

In fact, in the side of the lake, and now above the surface of the
water, appeared the long-looked-for opening. A narrow ridge, left bare
by the retreat of the water, allowed them to approach it. This orifice
was nearly twenty feet in width, but scarcely two in height. It was like
the mouth of a drain at the edge of the pavement, and therefore did
not offer an easy passage to the settlers; but Neb and Pencroft, taking
their pickaxes, soon made it of a suitable height.

The engineer then approached, and found that the sides of the opening,
in its upper part at least, had not a slope of more than from thirty to
thirty-five degrees. It was therefore practicable, and, provided that
the declivity did not increase, it would be easy to descend even to the
level of the sea. If then, as was probable, some vast cavity existed in
the interior of the granite, it might, perhaps, be of great use.

"Well, captain, what are we stopping for?" asked the sailor, impatient
to enter the narrow passage. "You see Top has got before us!"

"Very well," replied the engineer. "But we must see our way. Neb, go and
cut some resinous branches."

Neb and Herbert ran to the edge of the lake, shaded with pines and other
green trees, and soon returned with some branches, which they made
into torches. The torches were lighted with flint and steel, and Cyrus
Harding leading, the settlers ventured into the dark passage, which the
overplus of the lake had formerly filled.

Contrary to what might have been supposed, the diameter of the passage
increased as the explorers proceeded, so that they very soon were able
to stand upright. The granite, worn by the water for an infinite time,
was very slippery, and falls were to be dreaded. But the settlers were
all attached to each other by a cord, as is frequently done in ascending
mountains. Happily some projections of the granite, forming regular
steps, made the descent less perilous. Drops, still hanging from the
rocks, shone here and there under the light of the torches, and
the explorers guessed that the sides were clothed with innumerable
stalactites. The engineer examined this black granite. There was not a
stratum, not a break in it. The mass was compact, and of an extremely
close grain. The passage dated, then, from the very origin of the
island. It was not the water which little by little had hollowed it.
Pluto and not Neptune had bored it with his own hand, and on the wall
traces of an eruptive work could be distinguished, which all the washing
of the water had not been able totally to efface.

The settlers descended very slowly. They could not but feel a certain
awe, in this venturing into these unknown depths, for the first time
visited by human beings. They did not speak, but they thought; and
the thought came to more than one, that some polypus or other
gigantic cephalopod might inhabit the interior cavities, which were in
communication with the sea. However, Top kept at the head of the little
band, and they could rely on the sagacity of the dog, who would not fail
to give the alarm if there was any need for it.

After having descended about a hundred feet, following a winding road,
Harding who was walking on before, stopped, and his companions came up
with him. The place where they had halted was wider, so as to form a
cavern of moderate dimensions. Drops of water fell from the vault, but
that did not prove that they oozed through the rock. They were simply
the last traces left by the torrent which had so long thundered through
this cavity, and the air there was pure though slightly damp, but
producing no mephitic exhalation.

"Well, my dear Cyrus," said Gideon Spilett, "here is a very secure
retreat, well hid in the depths of the rock, but it is, however,
uninhabitable."

"Why uninhabitable?" asked the sailor.

"Because it is too small and too dark."

"Couldn't we enlarge it, hollow it out, make openings to let in light
and air?" replied Pencroft, who now thought nothing impossible.

"Let us go on with our exploration," said Cyrus Harding. "Perhaps lower
down, nature will have spared us this labor."

"We have only gone a third of the way," observed Herbert.

"Nearly a third," replied Harding, "for we have descended a hundred feet
from the opening, and it is not impossible that a hundred feet farther
down—"

"Where is Top?" asked Neb, interrupting his master.

They searched the cavern, but the dog was not there.

"Most likely he has gone on," said Pencroft.

"Let us join him," replied Harding.

The descent was continued. The engineer carefully observed all the
deviations of the passage, and notwithstanding so many detours, he
could easily have given an account of its general direction, which went
towards the sea.

The settlers had gone some fifty feet farther, when their attention was
attracted by distant sounds which came up from the depths. They stopped
and listened. These sounds, carried through the passage as through an
acoustic tube, came clearly to the ear.

"That is Top barking!" cried Herbert.

"Yes," replied Pencroft, "and our brave dog is barking furiously!"

"We have our iron-tipped spears," said Cyrus Harding. "Keep on your
guard, and forward!"

"It is becoming more and more interesting," murmured Gideon Spilett in
the sailor's ear, who nodded. Harding and his companions rushed to the
help of their dog. Top's barking became more and more perceptible,
and it seemed strangely fierce. Was he engaged in a struggle with some
animal whose retreat he had disturbed? Without thinking of the danger
to which they might be exposed, the explorers were now impelled by an
irresistible curiosity, and in a few minutes, sixteen feet lower they
rejoined Top.

There the passage ended in a vast and magnificent cavern.

Top was running backwards and forwards, barking furiously. Pencroft and
Neb, waving their torches, threw the light into every crevice; and
at the same time, Harding, Gideon Spilett, and Herbert, their spears
raised, were ready for any emergency which might arise. The enormous
cavern was empty. The settlers explored it in every direction. There was
nothing there, not an animal, not a human being; and yet Top continued
to bark. Neither caresses nor threats could make him be silent.

"There must be a place somewhere, by which the waters of the lake
reached the sea," said the engineer.

"Of course," replied Pencroft, "and we must take care not to tumble into
a hole."

"Go, Top, go!" cried Harding.

The dog, excited by his master's words, ran towards the extremity of the
cavern, and there redoubled his barking.

They followed him, and by the light of the torches, perceived the mouth
of a regular well in the granite. It was by this that the water escaped;
and this time it was not an oblique and practicable passage, but a
perpendicular well, into which it was impossible to venture.

The torches were held over the opening: nothing could be seen. Harding
took a lighted branch, and threw it into the abyss. The blazing resin,
whose illuminating power increased still more by the rapidity of its
fall, lighted up the interior of the well, but yet nothing appeared. The
flame then went out with a slight hiss, which showed that it had reached
the water, that is to say, the level of the sea.

The engineer, calculating the time employed in its fall, was able to
calculate the depth of the well, which was found to be about ninety
feet.

The floor of the cavern must thus be situated ninety feet above the
level of the sea.

"Here is our dwelling," said Cyrus Harding.

"But it was occupied by some creature," replied Gideon Spilett, whose
curiosity was not yet satisfied.

"Well, the creature, amphibious or otherwise, has made off through this
opening," replied the engineer, "and has left the place for us."

"Never mind," added the sailor, "I should like very much to be Top just
for a quarter of an hour, for he doesn't bark for nothing!"

Cyrus Harding looked at his dog, and those of his companions who were
near him might have heard him murmur these words,—

"Yes, I believe that Top knows more than we do about a great many
things."

However, the wishes of the settlers were for the most part satisfied.
Chance, aided by the marvelous sagacity of their leader, had done them
great service. They had now at their disposal a vast cavern, the size
of which could not be properly calculated by the feeble light of their
torches, but it would certainly be easy to divide it into rooms, by
means of brick partitions, or to use it, if not as a house, at least as
a spacious apartment. The water which had left it could not return. The
place was free.