As promised, five days passed, and the ministers gathered at the Donggung Hall to assess the current state of the research institute. Not only the ministers came, but Sejong was also with them.
"I will go along as well."
"There is no need for Your Majesty to come…."
Hwang Hee tried to dissuade him, but Sejong stopped him.
"I am curious to see what the Crown Prince and those he leads have created during this time."
"Ah, yes…."
"Come, let's move quickly!"
As Sejong took the lead, the ministers followed with expressions of resignation.
When Sejong and the ministers arrived at the annex of the Donggung Hall, the Crown Prince and the officials from the research institute were already waiting and bowed respectfully.
"Your Majesty."
"You have been working hard. Let's see…."
Sejong carefully observed the people standing in front of the research institute. Initially, it started with Jeong Cho, Jeong Inji, and Lee Cheon, but now there were many more people standing behind them.
"The number of people has increased significantly?"
"It is still not enough."
"Still not enough?"
Sejong shook his head at Hwang's answer. There were at least twenty people standing before him, yet his son still said it was not enough.
"Let's discuss the issue of personnel and budget after seeing the results."
"Yes, Father."
Hwang led Sejong to the entrance of the research institute.
* * *
"Hmm?"
Upon entering the research institute, Sejong let out a curious exclamation. Along the corridor, bookshelves displayed various instruments instead of books.
"Let's see… the large and small gansui (water level gauges)…."
Sejong, who was examining the instruments and their nameplates, turned to Hwang.
"Is this all? Considering the budget allocated…."
"The items displayed here are all specimens for exhibition."
"Clack!"
In response to Sejong's question, Hwang opened the sliding door of a nearby room labeled 'Equipment Rental Room.' Inside, rows of drawers stood, each locked with thick padlocks. Hwang continued his explanation.
"The actual equipment is stored in these drawers."
"Management?"
Sejong pointed to the eunuchs standing at the door entrance.
"Two people are assigned to manage the entry and exit of the equipment."
"Thorough."
Sejong nodded, looking at the ledger on the desk. It meticulously recorded the date, the name of the visitor, the equipment taken out, and the return date.
"I have heard that I am also thorough…."
Continuously nodding, Sejong looked up from the ledger and praised the standing eunuchs.
"You have all worked very hard. Your efforts are for the benefit of the nation, so please continue to strive."
"Your grace is boundless!"
After leaving the Equipment Rental Room, Sejong examined the instruments displayed on the bookshelves again.
"Hmm…, wait. A level and a plumb line?"
"These are instruments for measuring horizontal and vertical alignment."
"Hmm?"
Sejong, intrigued, picked up the level. It was a long wooden board with a metal component in the center. Inside the long, hollow metal plate was a cylindrical metal piece.
"Clack. Clack."
As Sejong moved the wooden board, the cylindrical piece inside made sounds and moved from side to side.
"When the cylinder stops in the center, it indicates perfect horizontal and vertical alignment."
"Ah, I see!"
King Sejong, now understanding how to use the level and plumb line, became even more curious.
"So, where are these used?"
"In construction."
"In construction?"
"Yes. When installing instruments for astronomical measurements, the most important thing is to ensure that the base is perfectly horizontal and vertical. Using the level and plumb line makes this task easier and more accurate."
"Ah!"
Sejong nodded in agreement and exclaimed in admiration. The ministers standing behind him felt the same way.
In particular, the Minister of Personnel, burning with greed, immediately advised Sejong.
"Your Majesty! The most important thing in constructing walls, government offices, and building dams and reservoirs is to ensure proper horizontal and vertical alignment! Using such instruments will make the task much easier, so they should be mass-produced and distributed immediately!"
"I also think so. Crown Prince."
When Sejong called, Hwang shook his head.
"Please forgive me, but the current versions are not yet complete."
"Not yet complete?"
"Yes, Father. The current versions are made using iron and copper, which easily rust. To prevent rust, they need to be oiled frequently and managed carefully, which is cumbersome. We are working on a solution, and an improved version will be available soon."
"Your Highness! When will the improved version be available?"
"I am also curious."
The Minister of Personnel, eager to get his hands on the instruments, pressed on. Sejong, seeing his expression, sighed.
* * *
Sejong was in a dilemma. Hwang's words made sense, and so did the Minister of Personnel's.
During the spring famine, when construction projects were carried out nationwide, Sejong had visited a construction site near Hanyang under the pretext of comforting the people.
"Your Majesty!"
The officials supervising the construction bowed, and the people working on the site stopped their work to bow deeply or kneel on the ground.
"You have worked hard. It is tough now, but once this construction is complete, it will greatly benefit farming, so please keep up the good work."
"Understood!"
"Long live the King! Long live the King! Long live the King!"
The people cheered in response to Sejong's praise. As he comforted the people and inspected the site, Sejong asked the supervising official.
"What is the most difficult part of the construction?"
The official immediately answered Sejong's question.
"Ensuring proper horizontal and vertical alignment."
"Why?"
"Simply put, building a reservoir or a dam is not difficult once you dig deep enough. However, the sluice gates and canals connected to them are not so easy. If the sluice gates are not properly aligned vertically, it becomes difficult to open and close them and to control the water. If the canals are not properly aligned horizontally and at the right slope, the water does not flow smoothly."
"I see."
Sejong nodded in agreement with the official's answer.
Later, when the construction of the annex of the Donggung Hall was underway, he had also observed the work. The most meticulous part was ensuring the horizontal and vertical alignment of the pillars and beams.
* * *
Because of this experience, Sejong understood why the Minister of Personnel was so excited.
"What to do…."
After much deliberation, Sejong made a decision.
"Crown Prince, you say it is not yet complete, but to me, it already seems capable of doing its job. Provide the related technology to the Ministry of Personnel."
"…Understood. I will follow Father's command. By the way, there are a few more instruments related to this. Would you like to see them?"
"Sure, let's see them."
Hwang showed Sejong and the ministers a few more instruments. These included a compass, a set square, a circular protractor that could measure 360 degrees, and an angle gauge that could adjust up to 180 degrees. The angle gauge, in particular, had a locking mechanism using screws, allowing it to be firmly fixed at the desired angle.
"The carpenters and various craftsmen have been using similar instruments for generations. These are more precise versions of those instruments, the result of the hard work of the people at the research institute."
"Truly remarkable!"
Sejong genuinely admired the value of the instruments Hwang presented. Although Hwang said this, Sejong knew exactly where the ideas came from.
'Not from the rigid minds of the officials!'
Sejong looked at the Minister of Personnel, who could hardly hide his eagerness to take the instruments. With a proud expression, Sejong teased the ministers following him.
"Do you know what I am feeling now?"
"I am not sure."
"The Crown Prince is so outstanding that I want to issue a pardon to celebrate."
"Your Majesty!"
"It's a joke, a joke."
Although he said it was a joke, Sejong's expression was serious.
'Look! My son is so smart! Do you have such a smart child?'
Having made the decision regarding the instruments for construction and civil engineering, Sejong began to inspect the next set of instruments on display.
"Is this a ship?"
"Yes. The ship you are looking at is the largest warship currently used by our Joseon navy, the Byungchoson. The next ones are new ships under research."
"Hmm? They vary in size?"
"They are all models made to the same scale."
"Ah? Then…."
Sejong's gaze stopped at the model of a large ship at the end.
"It's quite large?"
"This is a model of the ship the researchers are working on."
Sejong's attention was drawn to the model of a ship of the line.
"Ship of the line? I don't see any oars?"
"It moves purely by wind power."
"What about armaments?"
"The main armament is cannons. According to calculations, it can carry at least 80 cannons."
"80 cannons!"
Hwang explained about the ship of the line.
"… Therefore, these ships form a line to maximize their firepower and fire the cannons. That's why they are called ships of the line."
"Truly an impressive name. So, Crown Prince, based on your and the researchers' findings, you suggest using the panokson for coastal waters and these ships of the line for long-distance voyages?"
"Yes, Father."
"Hmm."
Sejong stroked his beard in response to Hwang's answer.
"By the way."
Sejong recalled a report submitted by the Minister of War a while ago.
It was a report submitted by the newly established General Staff Headquarters and Training Institute of the Joseon Army, emphasizing the need for naval reform and the creation of a plan for it. Sejong had immediately approved the report.
"Land defense is important, but so is maritime defense. I grant permission."
Of course, the other ministers, except for the Minister of War, had opposed it due to budget concerns. However, Sejong did not waver in his decision.
"If we do not even make plans due to a lack of budget, that is what fools do! The budget is gradually increasing, so this is not a problem."
With Sejong's strong push, the ministers fell silent. They did not want to follow in the footsteps of Ryu Jeonghyeon.
While inspecting the models and listening to Hwang's explanation, Sejong raised a question. There was a bowl of cold noodles at the end of the ship models.
"Why is this noodle bowl here?"
"It symbolizes a ship made of iron, not wood."
"A ship made of iron?"
Sejong and the ministers all looked at Hwang in surprise.
* * *
"Did you say a ship made of iron?"
"Yes."
Hwang's answer made everyone, from Jeong Cho to Jang Youngsil, shake their heads.
"That is impossible."
"Even a child knows that iron sinks in water."
"You are right. Making a ship out of iron is impossible."
Hwang countered their negative responses.
"You are all wrong. It is not impossible; we just haven't found the method yet."
"Haven't found the method?"
"Yes."
Hwang gave a short answer and called an eunuch to give an order.
"Go to the kitchen and bring a bowl of noodles made of bronze and a basin filled with water."
"Yes, Your Highness."
A short while later, the eunuchs brought a basin filled with water and a bowl of cold noodles.
"Place the basin on that table."
"Yes, Your Highness."
After the eunuchs placed the basin on the table, Hwang floated the bowl of cold noodles on top of it.