Chapter 17 Chapter Seventeen

The next day, May 7th, Smith and Keating.Spilett climbed Prospect Heights, Herbert and Pencroft set out up the river to get some more firewood, leaving Neb alone at home to prepare breakfast. The engineer and correspondent soon came to the little sandy beach where the dugong was stranded, just to the south of the lake.A flock of birds was already pecking at its flesh, and Cyrus, intending to save the meat for the party, drove the birds away with stones.The meat of this animal is excellent food, and in the Malay Archipelago and in some other places, the special dish of the local princes and grandchildren.But it was up to Neb to do it himself.

At this time Cyrus.Smith had a new idea.He was greatly interested in what happened yesterday.He intended to unravel the mystery of the underwater battle, and to establish what monster had inflicted such strange wounds on the dugong.He stood by the lake for a long time, looking and looking, but there was nothing but the glint of the calm waters of the morning light. Near the sandy beach where the dugongs ran aground, the lake is relatively shallow, but from here, the bottom of the lake gradually slopes down. It is estimated that the center of the lake may be quite deep.The whole lake is like a huge central basin, which is filled by the flow of the Red River.

Cyrus, the correspondent said, there seemed nothing suspicious at the bottom. Indeed, my dear Spilett, replied the engineer, I do not know how to explain what happened yesterday. I admit, says Spilett, that at least the dugong's wound is curious.And I don't understand how Top was thrown so violently over the water?Those who don't know must have thought that a powerful arm threw it up, and then bayoneted the dugong to death! Yes, said the engineer, lost in thought at this moment, there are things I really don't understand.But do you understand another question better, my dear Spilett.How on earth was I saved, dragged out of the waves and carried to the dunes?yes!Isn't this a problem?Now I am sure that there must be some secret here, which will undoubtedly be revealed in the future.We may wish to observe carefully, but without discussing these strange things in front of everyone, we will keep these words in our hearts and continue our work.

It is always remembered that the engineer had so far found no place where the excess lake water had escaped, but he knew there must be such a place.Here he saw a rapid current and was very surprised.He threw a few pieces of wood into the water and found it flowing towards the south corner.He followed the current and reached the southern end of the lake. Here the lake has sunk, as if part of the water had leaked into the cracks in the ground. Smith put his ears on the ground as high as the lake and listened quietly. He clearly heard the sound of the underground waterfall. There is a place for drainage.As he said, he stood up, no problem, the lake flows through a passage in the granite wall, and goes straight to the sea, and we can use the cave through which it flows.Lo and behold, I was able to find it!

The engineer cut a very long branch, removed the leaves, and placed it at the corner of the bank.He found a large hole just a foot below the surface of the water.This was the drain they hadn't found for a long time. The force of the water flow was so strong that even the branches in the engineer's hand were washed away without a trace. Now there is no doubt, repeated Smith, the exit is here, I will open it and see! What are you going to do?Ji Ding.asked Spilett. Lower the level of the lake three feet. How do you lower the lake level? Open an outlet bigger than this one. Where is it, Cyrus?

Located closest to the beach. But it was a piece of granite!Spilett said. Well, Cyrus.Smith said, I want to blast the granite rocks, and after the water flows out, the lake level will be lower, and then the hole will be exposed A waterfall can be created to pour water onto the beach.The correspondent added. Carve out a waterfall we can take advantage of!Come on, come on, said Cyrus! The engineer hurried his partner away, and the correspondent had complete confidence in Smith, who had no doubt that the enterprise would fail.However, without gunpowder and incomplete tools, how can we blast the granite wall?Although engineers are very enthusiastic about this job, isn't their ability not enough?

Herbert and Pencroft were unloading wood from the raft when Smith and the correspondent returned to the grotto. The woodcutter's work is just done, Mr Smith, laughed the sailor, when you want a plasterer Plasterers, no, now chemists.replied the engineer. By the way, the correspondent continued, we are going to bomb the island Fry the island?cried Pencroft. Fry at least part of it.replied Spilett. Listen to me, friends.said the engineer.Then he announced the results of the inspection to everyone. According to the engineer, however large or small, there must be a cave in the granite wall below Prospect Heights.He planned to break through the stone wall and go inside.For this purpose it was first necessary to cut a larger outlet, lower the level of the lake, and then clear the cave through which the rapids passed.A charge was therefore to be made to blow a deep ditch in other parts of the shore.This was Smith's plan to use the minerals that nature provided him.

It is needless to say that the plan was unanimously and enthusiastically supported, especially by Pencroft.Carrying out large-scale work, blasting granite rock, and artificially creating waterfalls are all things that suit the sailor's appetite.Now that the engineer needs chemicals, he becomes a chemist again just as he once became a mason and cobbler.He could do what the people wanted, and, as he told Neb, he could even be a teacher of dancing and etiquette if necessary. Neb and Pencroft were first sent to fetch the dugong's oil, and save its flesh for consumption.They trusted the engineer so much that they set off right away without asking a word.A few minutes later, Cyrus.Smith, Herbert and Keating.Spilett also took his basket to the coal seam, where the nearest transitional strata contained a great deal of pyrite, of which Smith had previously found a specimen.They spent a whole day transporting the ore back to the grotto, and in the evening, several tons of these ores had already been transported.

The next day, May 8, the engineers set to work.The main components of these pyrites are charcoal, flint, bauxite and iron sulfide. The content of iron sulfide is too much, so it must be separated and turned into sulfate as soon as possible.After the sulfate is obtained, the sulfuric acid can be distilled out. Their purpose is to obtain sulfuric acid.Sulfuric acid is an indispensable raw material. According to the consumption of sulfuric acid, the industrial production of a country can be estimated.This acid is very useful, and the residents can use it to make candles, tan leather, etc. in the future, but this time the engineer has another use and kept it.

Cyrus.Smith found a very flat place behind the grotto. He laid a layer of branches and firewood on the ground, piled a few pieces of pyrite on top of each other, and covered it with a thin layer of pyrite. This was broken in advance, and they were about the size of walnuts. When this was done, they lighted the wood, and the heat spread to the schist, which contained charcoal and sulfur, and immediately ignited.Then they added several layers of crushed ore, piled it up in a big pile, covered it with dry soil and weeds, and left holes for ventilation, as if they were burning a pile of firewood into charcoal.

The process of turning iron sulfide into iron sulfate and alumina into aluminum sulfate takes at least ten to twelve days. After the above arrangement, they let it change by itself and no longer care about it.Both iron sulfate and aluminum sulfate can be dissolved in water, but others such as flint, coke, ash, etc. cannot be dissolved in water. While doing this chemical work, Cyrus.Smith went on to other jobs, and they worked very hard, hoping for instant success. Neb and Pencroft had removed all the fat from the dugong, and put them in great clay pots.Now it is necessary to separate the glycerin from the fat by alkalization.To do the job, one must have baking soda or lime, either of which breaks down the fat and forms soap and separates out the glycerin, which is exactly what the engineer wanted.It is convenient to pour lime, but the soap obtained in this way is calcareous, insoluble in water, and therefore useless.Conversely, if you use baking soda, you can get a soap that dissolves and can be used every day.Cyrus.Smith is a practical guy who would rather go to the trouble of getting baking soda.Is it difficult?No, because there are many aquatic plants on the shore, including salicornia, apricot and various Sargassum that floated ashore.They collected the plants in large quantities, dried them in the sun, and burned them in pits in the open air.They burned for several days, and the result was a lot of gray powder, which has long been called natural baking soda. With baking soda, engineers used it to combine fats, resulting in both soluble soap and an intermediate substance, glycerin. But that's not all.For the sake of future work, Cyrus.Smith needed one more thing, and that was potassium nitrate, commonly called nitrate, also known as saltpeter. Cyrus.Smith can make potassium nitrate by combining nitric acid and potassium carbonate, which is easily obtained from plant ash.The problem was nitric acid, and he would have had some difficulty if nitric acid hadn't been as readily available as other substances.Fortunately Herbert discovered a vein of nitrate at the foot of the Franklin Mountains, and they had only to refine the salt. These various works continued for a week, and were completed before the iron sulphide became iron sulphate.In the remaining few days, the residents seized the time and built a special brick furnace to prepare for the distillation of iron sulfate that has not yet been produced.By about the eighteenth of May, this was all completed almost simultaneously with the chemical transformation.For a few days, Keating.Spilett, Herbert, Neb, and Pencroft, under the clever direction of the engineer, became the ablest workmen.Practical needs are the most convincing and most instructive teachers. After heating the large heap of pyrite ore, which was completely reduced, they put the obtained iron sulfate, aluminum sulfate, flint, cinder and ashes all in a basin filled with water, and stirred the mixture for a while. , then let it settle, and pour out the water, to obtain a pure liquid containing a solution of ferric sulphate and aluminum sulphate, and other insoluble substances, which remain solid.Finally, part of the evaporated liquid forms ferric sulfate crystals, and the rest of the unevaporated liquid containing aluminum sulfate is discarded. Cyrus.Smith now has a large amount of iron sulfate crystals that can be used to extract sulfuric acid.Manufacturing sulfuric acid is costly.A lot of equipment is necessary, such as: a set of special tools, platinum instruments, lead chambers that are not afraid of acid corrosion, in which chemical changes can be carried out, etc.The engineer had none of these things in his hands, but he knew that, especially in Bohemia, there was a very simple way of making sulfuric acid, which also had the advantage of being able to produce sulfuric acid of very high concentration, the Nordic sulfuric acid being made of made in this way. Cyrus.Smith’s final process of making sulfuric acid is to seal the crystals of ferric sulfate in a bottle, calcine them, evaporate them into water vapor, and turn them into sulfuric acid after cooling. They put the crystals in the pot, lit the fire, and the crystals evaporated into sulfuric acid, and the work was successfully completed.On May 20th, that is, the twelfth day after starting work, the engineer obtained a large quantity of sulfuric acid, which he intended to use in various ways in the future. Why does he want the chemical now?Just to make nitric acid, it is very simple to make nitric acid, as long as sulfuric acid and saltpeter are combined, nitric acid can be distilled out. But what exactly did he use the nitric acid for?The partners don't know yet, because he hasn't announced his purpose to everyone. However, the engineer's goal is almost achieved. After one more process, what he has worked so hard to dream of can be manufactured. He had previously concentrated the glycerin by evaporation, and now he mixed a small amount of nitric acid with glycerin in a sink.So, without even using coolant, you get several pints of yellow mixed oil. While carrying out the last process, Cyrus.In order to avoid endangering everyone in case of an explosion, Smith left the grotto for a distance and found a remote place to deal with it alone.When it was finished, he showed his friends a bottle and said triumphantly: It's nitroglycerin! It is true that this is a terrible drug, its explosive power is about ten times greater than that of ordinary explosives, and its explosions often cause accidents, but since people have discovered the method of making it explosives, they use a porous, It is safer to mix it with a liquid-absorbing solid (clay or sugar) and use this dangerous liquid.However, when the residents were operating on Lincoln Island, they were not aware of this method. Shall we just use this liquid to fry rocks?asked Pencroft suspiciously. Yes, my friend, said the engineer, this nitroglycerin produces great power.Because granite is very hard and has great resistance, it explodes even more powerfully. When shall we see and see, Mr. Smith? Tomorrow, it's time to dig a hole to bury the explosives.replied the engineer. The next day, May 21, at dawn, the sappers were in the area along the eastern shore of Lake Grant.It's only five hundred feet from the sea.The plateau slopes downward from the water's edge, and the lake is only blocked by a granite perimeter.Therefore, as long as the outer periphery is blasted, the lake water will rush out of the gap, forming a small river, rushing along the slope of the highland all the way to the beach.In this way, the lake level will be greatly lowered, and the stone caves for water discharge will be exposed. Their purpose is the last point. Under the direction of the engineer, Pencroft, with a pickaxe, hewed deftly and vigorously into the granite ground.The pit was dug on the bank's slope, much lower than the lake's surface.In this way, after the rock is blasted, there can be a fairly large gap for the lake to flow out. The work took some time, and the engineer, in order to achieve greater effect, decided to use at least seven quarts of nitroglycerin for the explosion.Pencroft and Neb, alternating their shifts, worked well, and by four o'clock in the afternoon the charges were laid. Now there is another problem, that is, how to light the explosives.Generally, the explosion of nitroglycerin is caused by the explosion of thunder mercury.There must be a momentum to erupt, and ignition can only make it burn, not produce an explosion. Of course, Cyrus.Smith is able to make thunderbolt.Although he lacks thunder powder, it is easy to make something like cotton powder, because he has nitric acid.As long as this drug is stuffed in a cartridge, and nitroglycerin is added, it can be burst with a matchlock to produce an explosion. Nitroglycerin can also explode under impact, this point Cyrus.Smith knew it.So he decided to use this method, and if that didn't work, try something else. In fact, just drop a small amount of nitroglycerin on a hard rock, hit it with a hammer, and it will instantly explode.But in order to do this, the person who struck the hammer must sacrifice himself.So Smith managed to use a plant fiber rope to hang a piece of iron weighing several kilograms above the explosive hole.Another long rope, preliminarily dipped in sulphur, was tied at one end to the center of the first rope, and the other end was drawn to the ground a few feet from the charge.After setting the sulfur-soaked rope on fire, it will soon burn to the joint with the first rope.As long as the fire reaches the joint, the first rope will burn and the iron will fall on the nitroglycerin.When equipped, the engineer directed his companions to retreat to a considerable distance, and he filled the pit with nitroglycerine until it was level with the mouth of the pit.Then he dripped a few more drops on the surface of the rock, by which time the iron block was suspended. After placing them, Smith lit the rope stained with sulfur, then left here, and walked towards the grotto with his companions. The rope was estimated to burn for twenty-five minutes.Sure enough, after twenty-five minutes, only an earth-shattering explosion was heard.The island seemed to shake at its very roots.Stones flew into the sky like a volcanic eruption.The violent vibration of the air produced a huge force, causing the rocks in the grotto to tremble.Residents were thrown to the ground even though they were two miles away. The shore must have exploded, and they got up and scrambled up to the plateau, heading straight for the shore. They cheered!I saw a large piece of the granite wall cracked!A torrent of white water rolls across the plateau and falls straight down the beach from a height of three hundred feet!