The next day, the 7th of May, Harding and Gideon Spilett, leaving Neb to
prepare breakfast, climbed Prospect Heights, while Herbert and Pencroft
ascended by the river, to renew their store of wood.
The engineer and the reporter soon reached the little beach on which the
dugong had been stranded. Already flocks of birds had attacked the mass of
flesh, and had to be driven away with stones, for Cyrus wished to keep the
fat for the use of the colony. As to the animal's flesh it would furnish
excellent food, for in the islands of the Malay Archipelago and elsewhere,
it is especially reserved for the table of the native princes. But that was
Neb's affair.
At this moment Cyrus Harding had other thoughts. He was much interested
in the incident of the day before. He wished to penetrate the mystery of
that submarine combat, and to ascertain what monster could have given the
dugong so strange a wound. He remained at the edge of the lake, looking,
observing; but nothing appeared under the tranquil waters, which sparkled
in the first rays of the rising sun.
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.
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!