Books: The Mysterious Island

J >> Jules Verne >> The Mysterious Island

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When Harding and the reporter entered the Chimneys, they found Herbert
and Pencroft unloading their raft of wood.

"The woodmen have just finished, captain." said the sailor, laughing, "and
when you want masons--"

"Masons,--no, but chemists," replied the engineer.

"Yes," added the reporter, "we are going to blow up the island--"

"Blow up the island?" cried Pencroft.

"Part of it, at least," replied Spilett.

"Listen to me, my friends," said the engineer. And he made known to them
the result of his observations.

According to him, a cavity, more or less considerable, must exist in the
mass of granite which supported Prospect Heights, and he intended to
penetrate into it. To do this, the opening through which the water rushed
must first be cleared, and the level lowered by making a larger outlet.
Therefore an explosive substance must be manufactured, which would make a
deep trench in some other part of the shore. This was what Harding was
going to attempt with the minerals which nature placed at his disposal.

It is useless to say with what enthusiasm all, especially Pencroft,
received this project. To employ great means, open the granite, create a
cascade, that suited the sailor. And he would just as soon be a chemist as
a mason or bootmaker, since the engineer wanted chemicals. He would be all
that they liked, "even a professor of dancing and deportment," said he to
Neb, if that was ever necessary.

Neb and Pencroft were first of all told to extract the grease from the
dugong, and to keep the flesh, which was destined for food. Such perfect
confidence had they in the engineer, that they set out directly, without
even asking a question. A few minutes after them, Cyrus Harding, Herbert,
and Gideon Spilett, dragging the hurdle, went towards the vein of coals,
where those shistose pyrites abound which are met with in the most recent
transition soil, and of which Harding had already found a specimen. All the
day being employed in carrying a quantity of these stones to the Chimneys,
by evening they had several tons.

The next day, the 8th of May, the engineer began his manipulations. These
shistose pyrites being composed principally of coal, flint, alumina, and
sulphuret of iron--the latter in excess--it was necessary to separate the
sulphuret of iron, and transform it into sulphate as rapidly as possible.
The sulphate obtained, the sulphuric acid could then be extracted.

This was the object to be attained. Sulphuric acid is one of the agents
the most frequently employed, and the manufacturing importance of a nation
can be measured by the consumption which is made of it. This acid would
later be of great use to the settlers, in the manufacturing of candles,
tanning skins, etc., but this time the engineer reserved it for another
use.

Cyrus Harding chose, behind the Chimneys, a site where the ground was
perfectly level. On this ground he placed a layer of branches and chopped
wood, on which were piled some pieces of shistose pyrites, buttressed one
against the other, the whole being covered with a thin layer of pyrites,
previously reduced to the size of a nut.

This done, they set fire to the wood, the heat was communicated to the
shist, which soon kindled, since it contains coal and sulphur. Then new
layers of bruised pyrites were arranged so as to form an immense heap, the
exterior of which was covered with earth and grass, several air-holes being
left, as if it was a stack of wood which was to be carbonized to make
charcoal.

They then left the transformation to complete itself, and it would not
take less than ten or twelve days for the sulphuret of iron to be changed
to sulphate of iron and the alumina into sulphate of alumina, two equally
soluble substances, the others, flint, burnt coal, and cinders, not being
so.

While this chemical work was going on, Cyrus Harding proceeded with other
operations, which were pursued with more than zeal,--it was eagerness.

Neb and Pencroft had taken away the fat from the dugong, and placed it in
large earthen pots. It was then necessary to separate the glycerine from
the fat by saponifying it. Now, to obtain this result, it had to be treated
either with soda or lime. In fact, one or other of these substances, after
having attacked the fat, would form a soap by separating the glycerine, and
it was just this glycerine which the engineer wished to obtain. There was
no want of lime, only treatment by lime would give calcareous soap,
insoluble, and consequently useless, while treatment by soda would furnish,
on the contrary, a soluble soap, which could be put to domestic use. Now, a
practical man, like Cyrus Harding, would rather try to obtain soda. Was
this difficult? No; for marine plants abounded on the shore, glass-wort,
ficoides, and all those fucaceae which form wrack. A large quantity of
these plants was collected, first dried, then burnt in holes in the open
air. The combustion of these plants was kept up for several days, and the
result was a compact gray mass, which has been long known under the name of
"natural soda."

This obtained, the engineer treated the fat with soda, which gave both a
soluble soap and that neutral substance, glycerine.

But this was not all. Cyrus Harding still needed, in view of his future
preparation, another substance, nitrate of potash, which is better known
under the name of salt niter, or of saltpeter.

Cyrus Harding could have manufactured this substance by treating the
carbonate of potash, which would be easily extracted from the cinders of
the vegetables, by azotic acid. But this acid was wanting, and he would
have been in some difficulty, if nature had not happily furnished the
saltpeter, without giving them any other trouble than that of picking it
up. Herbert found a vein of it at the foot of Mount Franklin, and they had
nothing to do but purify this salt.

These different works lasted a week. They were finished before the
transformation of the sulphuret into sulphate of iron had been
accomplished. During the following days the settlers had time to construct
a furnace of bricks of a particular arrangement, to serve for the
distillation of the sulphate or iron when it had been obtained. All this
was finished about the 18th of May, nearly at the time when the chemical
transformation terminated. Gideon Spilett, Herbert, Neb, and Pencroft,
skillfully directed by the engineer, had become most clever workmen. Before
all masters, necessity is the one most listened to, and who teaches the
best.

When the heap of pyrites had been entirely reduced by fire, the result of
the operation, consisting of sulphate of iron, sulphate of alumina, flint,
remains of coal, and cinders was placed in a basinful of water. They
stirred this mixture, let it settle, then decanted it, and obtained a clear
liquid containing in solution sulphate of iron and sulphate of alumina, the
other matters remaining solid, since they are insoluble. Lastly, this
liquid being partly evaporated, crystals of sulphate of iron were
deposited, and the not evaporated liquid, which contained the sulphate of
alumina, was thrown away.

Cyrus Harding had now at his disposal a large quantity of these sulphate
of iron crystals, from which the sulphuric acid had to be extracted. The
making of sulphuric acid is a very expensive manufacture. Considerable
works are necessary--a special set of tools, an apparatus of platina,
leaden chambers, unassailable by the acid, and in which the transformation
is performed, etc. The engineer had none of these at his disposal, but he
knew that, in Bohemia especially, sulphuric acid is manufactured by very
simple means, which have also the advantage of producing it to a superior
degree of concentration. It is thus that the acid known under the name of
Nordhausen acid is made.

To obtain sulphuric acid, Cyrus Harding had only one operation to make,
to calcine the sulphate of iron crystals in a closed vase, so that the
sulphuric acid should distil in vapor, which vapor, by condensation, would
produce the acid.

The crystals were placed in pots, and the heat from the furnace would
distil the sulphuric acid. The operation was successfully completed, and on
the 20th of May, twelve days after commencing it, the engineer was the
possessor of the agent which later he hoped to use in so many different
ways.

Now, why did he wish for this agent? Simply to produce azotic acid; and
that was easy, since saltpeter, attacked by sulphuric acid, gives azotic,
or nitric, acid by distillation.

But, after all, how was he going to employ this azotic acid? His
companions were still ignorant of this, for he had not informed them of the
result at which he aimed.

However, the engineer had nearly accomplished his purpose, and by a last
operation he would procure the substance which had given so much trouble.

Taking some azotic acid, he mixed it with glycerine, which had been
previously concentrated by evaporation, subjected to the water-bath, and he
obtained, without even employing a refrigerant mixture, several pints of an
oily yellow mixture.

This last operation Cyrus Harding had made alone, in a retired place, at
a distance from the Chimneys, for he feared the danger of an explosion, and
when he showed a bottle of this liquid to his friends, he contented himself
with saying,--

"Here is nitro-glycerine!"

It was really this terrible production, of which the explosive power is
perhaps tenfold that of ordinary powder, and which has already caused so
many accidents. However, since a way has been found to transform it into
dynamite, that is to say, to mix with it some solid substance, clay or
sugar, porous enough to hold it, the dangerous liquid has been used with
some security. But dynamite was not yet known at the time when the settlers
worked on Lincoln Island.

"And is it that liquid that is going to blow up our rocks?" said Pencroft
incredulously.

"Yes, my friend," replied the engineer, "and this nitro-glycerine will
produce so much the more effect, as the granite is extremely hard, and will
oppose a greater resistance to the explosion."

"And when shall we see this, captain?"

"To-morrow, as soon as we have dug a hole for the mine, replied the
engineer."

The next day, the 21st of May, at daybreak, the miners went to the point
which formed the eastern shore of Lake Grant, and was only five hundred
feet from the coast. At this place, the plateau inclined downwards from the
waters, which were only restrained by their granite case. Therefore, if
this case was broken, the water would escape by the opening and form a
stream, which, flowing over the inclined surface of the plateau, would rush
on to the beach. Consequently, the level of the lake would be greatly
lowered, and the opening where the water escaped would be exposed, which
was their final aim.

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!

Chapter 18

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.

Two difficulties remained; firstly, the possibility of lighting this
excavation in the midst of solid rock; secondly, the necessity of rendering
the means of access more easy. It was useless to think of lighting it from
above, because of the enormous thickness of the granite which composed the
ceiling; but perhaps the outer wall next the sea might be pierced. Cyrus
Harding, during the descent, had roughly calculated its obliqueness, and
consequently the length of the passage, and was therefore led to believe
that the outer wall could not be very thick. If light was thus obtained, so
would a means of access, for it would be as easy to pierce a door as
windows, and to establish an exterior ladder.