Innovation and Revolution (6)
In the face of the Eulmi War Rebellion, Yi Yeon had appointed Jeong Geol, who had rendered outstanding service, as a professor at the Hwaryeok Military Academy. It had nothing to do with simply helping and supporting Admiral Yi Sun-sin. It was the one stroke of genius Kim had mentioned, after all. Jeong Geol, who had been born and raised along the southern coast, knew the sea better than anyone else. He was deeply familiar not only with the construction of turtle ships but also with the thousand-pound cannons. Yet he had been serving as the governor of Jongseong, a border village in Hamgyeong Province.
No, what kind of appointment is this? A person who would barely make a decent naval commander was being assigned to northern administrative management. It was absurd. Even as a regional defense administrator, it made no sense. They should have been sent to the southern coast, where pirates swarmed without warning. Even Yi I would have been better off. If he had still been at court, he would not have been able to create a single ancient steam engine, let alone a revolutionary one. In any case, the task of modifying the pancok ships had been given to him. Kim Yang-bo had also selected Na Dae-yong from the intelligence agency and handed him over to Jeong Geol. “Train him as your disciple.”
Today, Na Dae-yong was once again aboard a pancok ship with Kim Ji, carrying out cannon-firing experiments off the Hampho fortress, just returning home. He had thought that to begin modification, one must first understand the performance of the newly manufactured cannons. “Very well. Can it be modified?” “Your Majesty, this humble one is truly honored, yet it may be difficult.” Yi Yeon smiled knowingly and looked at Yi I. “Now I can tell you about the hydraulic return-to-prime-position mechanism.”
Yi Yeon had ordered Kim Ji to convert the decorative cannons into fortress cannons. They were not to be placed inside the hull like the thousand-pound cannons, but mounted on the deck for rotation and firing. That way they could see and shoot far away, and even be fired on parabolic trajectories. But the problem was serious. The pivot on an iron base with a large bearing allowed rotation without issue, yet the ship itself shook violently with every shot. To counteract that, springs had been attached beneath the cannons, but the rebound made the shaking even worse. The cannons danced as if ready to fly off. Yi I, feeling the king’s gaze, swallowed hard. Each time a new piece of knowledge was revealed, he took it in. Yi Yeon shook his open palm like swatting a fly and asked, “What if you put this hand in water and shake it?” “Because of the resistance of water… Ah, I understand, Your Majesty.” Yi I, who already knew the flaw in the cannon, immediately grasped the king’s meaning. “Is that so?” “Yes, Your Majesty. Like a steam engine, we can build a cylinder filled with water inside. This will block the cannon’s recoil instead of a spring.” “Correct. Correct!” Yi Yeon gave a thumbs-up as if to say, “Well done, Yi I.” Kim Ji and Jeong Geol tilted their heads, unable to understand what they were talking about.
“However, water boils faster than oil and rusts iron.” “You mean we should use oil instead of water?” “Precisely. This way we can prevent the cylinder from oxidizing and deliver force evenly. We shall call this force hydraulics, using the oil.” “Ah…” Yi I’s face showed deep regret. Yi Yeon had suggested springs to reduce cannon recoil, but they had produced no effect. He had been pondering other solutions when the king offered such a simple one: pressure using oil. “Yet when we experimented with hydraulics, we discovered an extremely strange phenomenon.” “W-what is that phenomenon, Your Majesty?” Yi I stammered. Given that the king had called it miraculous, it must be something astonishing. Yi Yeon summoned Kim Yang-bo instead of answering. “Yang-bo, bring it here.” “Yes, Your Majesty.” Yi Yeon opened the box Kim Yang-bo had left behind and pulled out large and small syringes made of glass. “Do you know what this is?” “Yes, Your Majesty. These are the syringes used in the medical bureau.” “Correct. Now the artisans of Yeogye are making glass syringes, and we administer variolation with them. Thanks to advances in glass craftsmanship, we can create precise glass tubes that do not leak even without rubber. As a result, we can vaccinate twenty people from a single cultured egg.” Yi Yeon inserted the large and small syringes into a U-shaped frame with a brass tube and filled it with water. “Look closely.” “Yes, Your Majesty.” When Yi Yeon pressed the small syringe, the large one rose. When he pulled it out, it lowered. Yi I blinked, thinking it nothing special, and gazed at the king. But the king placed a lump of iron on the large syringe and pressed the small one. The heavy iron lump rose smoothly. “How is it?” “T-that seems similar to the principle of the lever, Your Majesty?” “Correct. With hydraulics, we can lift great forces with small ones. The force is transmitted equally even when the tubes are divided into multiple parts.” “Ah…” Yi I studied the syringes intently and let out a loud exclamation. He had finally understood why the king had brought them to explain hydraulics. “So by putting oil in the tube, sealing one end to only block impact, and connecting large and small tubes, the large tube will protect the firing shock while the small one will return the heavy barrel. If we insert a spring with appropriate pressure, we should quickly stabilize the shaking barrel.” “Your Majesty! I am deeply grateful for this revelation.” Yi I rose in alarm and bowed deeply. Yi Yeon smiled with satisfaction and nodded. Since there was no point in resisting, he had decided to enjoy it. He admired Yi I, who had immediately grasped Pascal’s Principle, the foundation of fluid mechanics.
Yet from one side, Na Dae-yong, who had been kneeling and listening attentively, muttered something. Kim Ji and Jeong Geol, still unable to understand, looked frustrated. Yi Yeon noticed and asked, “Na Dae-yong?” Na Dae-yong startled and immediately prostrated himself flat. “Y-yes, Your Majesty.” “What did you feel?” “L-low, Your Majesty, if we use the hydraulics you mentioned, we should be able to move the steering mechanism from a distance.” “Really? Come, tell me what you thought.” “Yes, Your Majesty.” Na Dae-yong laid out what he had thought. “That’s it! Exactly! You are truly a clever boy!” “No, Your Majesty. I have only applied what my teacher taught me.” Yi Yeon looked at Jeong Geol. Even though his student had only now understood hydraulics after hearing the explanation, his expression was extremely proud. Kim Ji was the same. “Na Dae-yong?” “Yes, Your Majesty.” “What happened today is not to be told to anyone. Do you understand?” “Yes, Your Majesty. My teacher said that leaking military secrets is tantamount to treason. So I will not tell even my parents.” “Very good. Truly outstanding.” “Thank you, Your Majesty.” Yi Yeon found Na Dae-yong very likable. He had selected the boy early, inspired by the fact that he had built a turtle ship, to raise him for something even greater, and had handed him to Jeong Geol. He suspected he could achieve more. “Come closer.” “Y-yes?” At fourteen, Na Dae-yong had a boyish face but an enormous build, looking like a young merchant. Yet he was afraid and gazed at his teacher. Yi Yeon had always warned him to be cautious before the king, so he hesitated to approach. Jeong Geol nodded with a proud expression, and only then did Na Dae-yong creep forward on his knees. “Today I will tell you everything I know. Listen well and create something wonderful.” “Yes, Your Majesty.” Yi Yeon, eyes sparkling with expectation, summoned Kim Yang-bo, who brought paper and pencils. With the boy watching, Yi Yeon began to explain while sketching. It was exactly like teaching a student from his previous life. “With hydraulics, heavy objects can be lifted lightly.” “With hydraulics, the ground itself can be easily moved.” “With hydraulics, even hard objects…” Yi Yeon drew structures of various machines that would operate: cranes, excavators, bulldozers, compressors, cutters, brakes, and more, explaining each in detail. From the side, Yi I had countless questions he wanted to ask but held them back and observed. Kim Ji and Jeong Geol were busy absorbing the information. Yi Yeon intended to teach these concepts to the artisans of Yeogye as well. But they were so terrified of the king that they gave up when he tried to start from the basics. In contrast, Na Dae-yong, who had been here nearly a year, had solid basic knowledge, not to mention terminology. Here lived a genius like Yi I and the greatest artisans of Joseon, so his knowledge was astonishing. And with the same intellectual curiosity as Yi I, teaching him was a pleasure. Thus Yi Yeon revealed far more than planned. “Na Dae-yong?” “Yes, Your Majesty.” “When modifying the pancok ships, since the rowing section below is unnecessary, we will build long water tanks there. By filling and emptying them, the ship can maintain stability even in rough waves.” “Like filling equal amounts of water on both sides of the bilge pump, is that right?” “Exactly!” Yi Yeon had planned to equip new pancok ships with ballast-water tanks. Making the tanks from thick zinc-coated iron sheet would prevent easy corrosion when salt water was added or removed, and it would be essential for stable navigation on rough oceans. But how to explain it? Filling the ship with sea water was not something one could simply say. Yet Na Dae-yong understood instantly and even nodded. Thanks to him, Jeong Geol, in charge of the pancok modification, no longer needed a separate explanation. The boy sitting nearby had grasped the principle at once. Shin Yi Yeon, overjoyed, explained what he had planned to tell Yi I later. With Na Dae-yong present, Yi I would not be distracted from building it. “Your Majesty, if we place a hydraulic device or cannon on this infinite-track system, one person could do many tasks.” “Yes. Exactly. If we connect the steam engine made by the Science Bureau director with these devices, you can create everything you imagine.” “Really?” “Of course it is real.” The conversation continued. Yi I, Kim Ji, and Jeong Geol joined in, and the talk flowed into the construction of new ships.
DIV style="text-align:centerpadding:30px 0margin:20px 0">
Bak Sun, who had also taken charge of the Hwaryeok Industrial Complex plan, decided to build a bridge across the Han River. That way, the movement of people and goods would be convenient, and the economy the king had spoken of could be activated even faster. But how could one build a bridge over the Han River? Only if there were no drought exposing the bottom. Yet even in drought, nothing like that happened on the Han River, because salt water still surged as far as Mapo Naru on high tide. Therefore the king had ordered the construction of a submerged weir below Deokyang Mountain Fortress. But how was one to build that? There were no rocky mountains nearby to quarry stones. King, as if he had guessed the worry, said he would send Tokye Ju to discuss and plan together. Someone who would have shouted that such a thing was impossible would have shouted so in the past. “Work together with the former palace attendant.” But now he could not even say that, yet he was actually looking forward to it. The straight roads connecting all eight provinces were Tokye Ju’s work, after all. “Your Excellency, Tokye Ju has arrived.” “Welcome him in at once.” “Yes, Your Excellency.” Bak Sun rose at once and stepped outside. Tokye Ju was not part of the court and held no official rank, yet everyone treated him as director of the Education Bureau or Science Bureau. He even received the same salary as them and, counting special bonuses, more than double. Moreover, a single word from him could change the terrain of Joseon. Who would dare ignore him? Bak Sun, with his coal-darkened face and gleaming white teeth, bowed slightly as he saw Tokye Ju smiling. Tokye Ju returned the bow in kind. “Welcome. Chief.” “It is an honor to meet you for the first time, Your Excellency.” “Please come inside.” “Thank you for receiving me.” “What kind of talk is that? It is an honor that you came to see me.” The two men sat facing each other across the table, looked at it, then immediately got down to business. Now they would sip tea, draw out the moment, check each other’s eyes, and only then begin the real discussion. No one did such a thing anymore. It was easier to finish quickly and have a proper meal afterward. A proper meal could use official national funds. It was not merely eating and drinking for pleasure; it was seen as an extension of the work itself. That was why problems were often discovered at the meals. Then they would immediately modify the plan. Tokye Ju unrolled the two scrolls he had brought onto the table. “Your Excellency, this map is drawn with Hanyang at its center, extending as far as one hundred twenty-five ri, that is, fifty kilometers.” “Ah…” Bak Sun could only sigh in admiration. The height and depth of the terrain were shown in detail. The two men examined the map together, point by point. “From now on, this place will be the Hwaryeok Industrial Complex that will transform Joseon innovatively.” “Understood. But how will you handle the water source? Factories require a great deal of water, you know.” “That is why we will build a submerged weir here and dig a canal to it to supply water.” “Dig a canal?” “Yes, Your Excellency. Only then can we supply water all the way here.” “But how are we to dig through that place?” Tokye Ju smiled and placed a rod he had brought onto the table. “This is called a stick gelatin bomb. Its explosive power is excellent. It is easy to use and safe.” “Eh?” Bak Sun picked up the dynamite-like object and examined it curiously from all sides.