The Mysterious Island (21 page)

At the beach, on which lay the body of the dugong, the water was
tolerably shallow, but from this point the bottom of the lake sloped
gradually, and it was probable that the depth was considerable in the
center. The lake might be considered as a large center basin, which was
filled by the water from the Red Creek.

"Well, Cyrus," said the reporter, "there seems to be nothing suspicious
in this water."

"No, my dear Spilett," replied the engineer, "and I really do not know
how to account for the incident of yesterday."

"I acknowledge," returned Spilett, "that the wound given this creature
is, at least, very strange, and I cannot explain either how Top was
so vigorously cast up out of the water. One could have thought that a
powerful arm hurled him up, and that the same arm with a dagger killed
the dugong!"

"Yes," replied the engineer, who had become thoughtful; "there is
something there that I cannot understand. But do you better understand
either, my dear Spilett, in what way I was saved myself—how I was drawn
from the waves, and carried to the downs? No! Is it not true? Now, I
feel sure that there is some mystery there, which, doubtless, we shall
discover some day. Let us observe, but do not dwell on these singular
incidents before our companions. Let us keep our remarks to ourselves,
and continue our work."

It will be remembered that the engineer had not as yet been able to
discover the place where the surplus water escaped, but he knew it must
exist somewhere. He was much surprised to see a strong current at this
place. By throwing in some bits of wood he found that it set towards the
southern angle. He followed the current, and arrived at the south point
of the lake.

There was there a sort of depression in the water, as if it was suddenly
lost in some fissure in the ground.

Harding listened; placing his ear to the level of the lake, he very
distinctly heard the noise of a subterranean fall.

"There," said he, rising, "is the discharge of the water; there,
doubtless, by a passage in the granite cliff, it joins the sea, through
cavities which we can use to our profit. Well, I can find it!"

The engineer cut a long branch, stripped it of its leaves, and plunging
it into the angle between the two banks, he found that there was a large
hole one foot only beneath the surface of the water. This hole was the
opening so long looked for in vain, and the force of the current was
such that the branch was torn from the engineer's hands and disappeared.

"There is no doubt about it now," repeated Harding. "There is the
outlet, and I will lay it open to view!"

"How?" asked Gideon Spilett.

"By lowering the level of the water of the lake three feet."

"And how will you lower the level?"

"By opening another outlet larger than this."

"At what place, Cyrus?"

"At the part of the bank nearest the coast."

"But it is a mass of granite!" observed Spilett.

"Well," replied Cyrus Harding, "I will blow up the granite, and the
water escaping, will subside, so as to lay bare this opening—"

"And make a waterfall, by falling on to the beach," added the reporter.

"A fall that we shall make use of!" replied Cyrus. "Come, come!"

The engineer hurried away his companion, whose confidence in Harding was
such that he did not doubt the enterprise would succeed. And yet, how
was this granite wall to be opened without powder, and with imperfect
instruments? Was not this work upon which the engineer was so bent above
their strength?

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.