"If the gunpowder has been improved, how is it ignited?"
"It uses the gunpowder created by His Highness the Crown Prince."
In response to Choe Hae-san's answer, Sejong pointed out a problem.
"Wouldn't that be too cumbersome? There would be another layer of gunpowder between the fuse and the main gunpowder."
The ministers accompanying Sejong all nodded in agreement with his observation.
Most of them were civil officials, but some had experience in the military, and even those who didn't had at least heard how cannons were used. Moreover, they had seen the demonstration, so they knew that a fuse was necessary to ignite the gunpowder.
In response to Sejong's criticism, Choe Hae-san immediately replied.
"Type B gunpowder does not use a fuse. It uses a cap, or rather, a copper percussion cap."
"Copper percussion cap?"
When Sejong expressed his confusion, Hyang quickly wrote the characters on a piece of paper and handed it to him.
"It's written like this."
"Hmm... Do you have a sample?"
In response to Sejong's question, Choe Hae-san moved a copper plate from one side of the table to Sejong.
"The smaller ones are for muskets, and the larger ones are for cannons."
"Hmm..."
Sejong carefully examined the copper percussion caps on the plate.
The musket caps were slightly smaller than a fingernail, and the cannon caps were about the size of a thumb joint.
After examining the device, Sejong looked at Choe Hae-san.
"Is a demonstration possible?"
"It's already prepared. This way."
Choe Hae-san led Sejong and the ministers to a place a short distance from the table.
The area Choe Hae-san led them to was about 20 zhang (about 60 meters) wide and 150 zhang (about 450 meters) long.
"Truly desolate."
Sejong expressed his thoughts upon seeing the place Choe Hae-san had led them to.
As Sejong described, the area was indeed desolate.
Except for where the people stood, the other three sides were surrounded by earthen walls at least two zhang high. The place where the people stood also had a wall made of sandbags stacked up to chest height. Inside the wall, there were several depressions scattered around.
As Sejong and the ministers took their places behind the earthen wall, Choe Hae-san began to speak.
"Then, let's start the demonstration. Begin!"
At Choe Hae-san's command, the artisans moved a small table to the front of the demonstration area. On the table were copper plates and small wooden barrels.
"The powder in the left barrel is Type A gunpowder, and the powder in the right barrel is Type B gunpowder."
As Choe Hae-san continued his explanation, the artisans used a porcelain spoon to scoop the gunpowder onto the copper plates and inserted fuses. After confirming that the fuses were properly inserted, the artisans lit them and stepped back.
Bang! Fizz.
The Type A gunpowder, with its fuse, exploded with smoke, but the Type B gunpowder only burned the fuse and then stopped.
"This time, we will use the percussion caps with the modified muskets. Begin."
At the command, the artisans brought two muskets. They loaded the muskets with gunpowder from the barrels, inserted a paper wad, and began to tamp it down with a ramrod.
After tamping it down firmly, the artisans pulled the hammer at the rear of the musket and inserted a percussion cap. After completing all the steps, they firmly held the musket stock under their right armpit, held the string connected to the hammer in their left hand, and aimed at the opposite wall.
"Fire! Fire! Fire!"
With a loud cheer, the artisans pulled the strings simultaneously, and both muskets spat out flames.
"Wow!"
"Amazing!"
As the two muskets spat out flames, the ministers exclaimed in amazement.
Sejong turned to Hyang.
"So, this is how you use it without a fuse? Hmm... It seems there are fewer constraints compared to using a fuse."
"Indeed, Your Majesty."
"Truly, your efforts have been great."
Sejong looked at Hyang with an approving expression. However, his face quickly turned serious as he asked a question.
"You said the name of the gunpowder you created is 'Pao.' Could it be that you used silver?"
"No, it uses mercury. While mercury is valuable, it is easier to obtain than silver, and since it is only used for ignition, the cost is lower than expected."
"Then, that's fortunate."
Sejong's face brightened at Hyang's answer about the lower cost. After all, gunpowder was a material that consumed a tremendous amount of resources.
With a much more relaxed expression, Sejong turned his head to the demonstration area.
"I also want to know about the other gunpowder the Crown Prince created. General."
"Yes, Your Majesty. Bring the Pao oil."
"Yes."
At Choe Hae-san's command, the artisans carefully brought a small wooden box.
"Tip the box to show the inside."
The artisans tilted the box so that Sejong and the ministers could see inside. In the middle of the box, filled with sawdust, was a small porcelain bottle.
After removing the porcelain bottle from the box, Choe Hae-san uncorked it and gently tilted it towards the empty ground.
Bang!
A drop of Pao oil fell from the bottle's mouth and hit the ground, causing a loud explosion.
"Ah!"
"Good heavens!"
Startled by the unexpected explosion, the ministers gasped, and Choe Hae-san introduced it with a mischievous smile.
"This is Pao oil."
"Amazing! Incredible! Crown Prince, truly amazing! This is indeed a fitting name for Pao oil! General, how powerful is it?"
"It is incomparable to the gunpowder used by our Joseon army. The difference is like heaven and earth. Prepare it."
"Yes, General."
The artisans prepared a demonstration to compare the power of black powder and Pao oil.
"This is a thick musket designed to test the power. The amount of gunpowder used is 1/4 liang (about 9g) on both sides. First, we will use Type B gunpowder."
The artisan packed 1/4 liang of Type B gunpowder into the musket and secured it to a tripod set up on the ground. Next, he attached a large, mushroom-shaped iron cap to the muzzle of the musket, which was tilted forward. After pulling the hammer and inserting the percussion cap, the artisan stepped back and shouted loudly.
"Fire! Fire! Fire!"
Bang!
With a loud explosion, the iron cap flew in a parabolic arc and landed on the ground.
The artisan began counting the distance while retrieving the string attached to the iron cap.
"1 bo! 2 bo!... Choe Hae-san quickly explained to Sejong.
"The distance can be confirmed in 1 bo increments."
"Is that so?"
"50 bo! (about 60 meters)"
"Now, we will experiment with Pao oil."
At Choe Hae-san's gesture, the artisans began preparing for the second shot. The artisans' movements as they loaded the musket with Pao oil were extremely cautious.
"Very careful, I see?"
In response to Sejong's question, Hyang immediately answered.
"It is extremely finicky."
"However?"
"Fire! Fire! Fire!"
While they were talking, the artisan who had finished the preparations pulled the string connected to the hammer.
Boom!
With an even louder and sharper explosion than the Type B gunpowder, the iron cap soared into the sky and flew far away.
After retrieving the iron cap, which had flown a considerable distance, the artisan called out the distance in a loud voice.
"110 bo (about 132 meters)!"
Sejong's eyes widened in surprise at the artisan's call.
"It flew more than twice as far?"
"Indeed, Your Majesty. Despite its finicky nature, its power is outstanding."
Seeing Hyang's expression as he answered, Sejong clicked his tongue.
"Tsk! From your expression, it seems it's not easy to use."
"Indeed, Your Majesty. Given our current situation in Joseon, Pao oil itself is not practical."
"Indeed."
Hyang's answer made Sejong sigh and smack his lips.
"Indeed."
"The same here."
The ministers, who were listening to Sejong and Hyang, also had similar expressions.
They knew the Crown Prince's character to prioritize performance, but he also considered production costs. However, the fact that the Crown Prince did not mention costs suggested that the court could bear the production costs. Yet, the Crown Prince had just described it as "not practical."
"How finicky must it be for you to say that?"
"It is extremely finicky."
Hyang explained the reasons to Sejong.
- First, production is impossible in the warmer spring and summer seasons. The synthesis process generates high heat, and there is a high risk of self-explosion or fire. He could only attempt synthesis after winter began and had to use large amounts of ice from the stone ice house.
- Extreme caution is required during the synthesis process. Since concentrated acid is used, protective gear must be worn to protect the skin on the hands and face, and a ventilation system is essential.
- Even a small amount of impurities can significantly increase the risk of self-explosion. Therefore, Hyang had to go through numerous purification processes before and after synthesis.
- Storage is also difficult. It is extremely sensitive to shock