The Mysterious Island Jules Verne (red white royal blue txt) 📖

“It is there,” said he, rising, “there that the water is discharged, there, doubtless, through a passage in the massive granite that it goes to join the sea, through cavities which we will be able to utilize to our profit! Well! I will find out!”

The engineer cut a long branch, stripped off its leaves, and, plunging it down at the angle of the two banks, he found that there was a large open hole a foot below the surface. This was the long-sought-for outlet, and such was the force of the current that the branch was snatched from his hands and disappeared.

“There can be no doubt of it now,” repeated the engineer. “It is the mouth of the outlet, and I am going to work to uncover it.”

“How?” inquired Spilett.

“By lowering the lake three feet.”

“And how will you do that?”

“By opening another vent larger than this.”

“Whereabouts, Cyrus?”

“Where the bank is nearest the coast.”

“But it is a granite wall,” exclaimed Spilett,

“Very well,” replied Smith. “I will blow up the wall, and the waters, escaping, will subside so as to discover the orifice⁠—”

“And will make a waterfall at the cliff,” added the reporter.

“A fall that we will make use of!” answered Cyrus. “Come, come!”

The engineer hurried off his companion, whose confidence in Smith was such that he doubted not the success of the undertaking. And yet, this wall of granite, how would they begin: how, without powder, with but imperfect tools, could they blast the rock? Had not the engineer undertaken a work beyond his skill to accomplish?

When Smith and the reporter re-entered the Chimneys, they found Herbert and Pencroff occupied in unloading their raft.

“The wood-choppers have finished, sir,” said the sailor, laughing, “and when you want masons⁠—”

“Not masons, but chemists,” interrupted the engineer.

“Yes,” added Spilett, “we are going to blow up the island.”

“Blow up the island?” cried the sailor.

“A part of it, at least,” answered the reporter.

“Listen to me, my friends,” said the engineer, who thereupon made known the result of his observations. His theory was, that a cavity, more or less considerable, existed in the mass of granite which upheld Prospect Plateau, and he undertook to penetrate to it. To do this, it was first necessary to free the present opening, in other words to lower the level of the lake by giving the water a larger issue. To do this they must manufacture an explosive with which to make a drain in another part of the bank. It was this Smith was going to attempt to do, with the minerals Nature had placed at his disposal.

All entered into the proposal with enthusiasm. Neb and Pencroff were at once detailed to extract the fat from the dugong and to preserve the flesh for food; and soon after their departure the others, carrying the hurdle, went up the shore to the vein of coal, where were to be found the schistous pyrites of which Smith had procured a specimen.

The whole day was employed in bringing a quantity of these pyrites to the Chimneys, and by evening they had several tons.

On the next day, the 8th of May, the engineer began his manipulations. The schistous pyrites were principally composed of carbon, of silica, of alumina, and sulphuret of iron⁠—these were in excess⁠—it was necessary to separate the sulphuret and change it into sulphate by the quickest means. The sulphate obtained, they would extract the sulphuric acid, which was what they wanted.

Sulphuric acid is one of the agents in most general use, and the industrial importance of a nation can be measured by its consumption. In the future this acid would be of use to the colonists in making candles, tanning skins, etc., but at present the engineer reserved it for another purpose.

Smith chose, behind the Chimneys, a place upon which the earth was carefully levelled. On this he made a pile of branches and cut wood, on which were placed pieces of schistous pyrites leaning against each other, and then all was covered over with a thin layer of pyrites previously reduced to the size of nuts.

This done, they set the wood on fire, which in turn inflamed the schist, as it contained carbon and sulphur. Then new layers of pyrites were arranged so as to form an immense heap, surrounded with earth, and grass, with air-holes left here and there, just as is done in reducing a pile of wood to charcoal.

Then they left the transformation to complete itself. It would take ten or twelve days for the sulphuret of iron and the alumina to change into sulphates, which substances were equally soluble; the others⁠—silica, burnt carbon, and cinders⁠—were not so.

While this chemical process was accomplishing itself, Smith employed his companions upon other branches of the work, which they undertook with the utmost zeal.

Neb and Pencroff had taken the fat from the dugong, which had been placed in large earthen jars. It was necessary to separate the glycerine from this fat by saponifying it. It was sufficient, in order to do this, to treat it with chalk or soda. Chalk was not wanting, but by this treatment the soap would be calcareous and useless, while by using soda, a soluble soap, which could be employed for domestic purposes, would be the result. Cyrus Smith, being a practical man, preferred to try to get the soda. Was this difficult? No, since many kinds of marine plants abounded on the shore, and all those fucaceæ which form wrack. They therefore gathered a great quantity of these seaweed, which were first dried, and, afterwards, burnt in trenches in the open air. The combustion of these plants was continued for many days, so that the heat penetrated throughout, and the result was the greyish compact mass, long known as “natural soda.”

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

But this was not all. Smith wanted, in view of his future operations, another substance, nitrate of potash, better known