Ch.122Finding Work (4)

“Bronze, 400kg…?”

Ugh, urgh…

No matter how I look at it, this is crossing the line. Even if Rotaring is wealthy, they can’t just casually use 400kg of bronze.

Of course, if we squeeze the national budget, we could gather some amount, but if we can barely collect materials through such extreme measures, it’s a failing grade for military equipment.

‘So that’s why… that was the only one that succeeded.’

What did they say before? That cannon was the only one where the projectile flew proportionally to the gunpowder used, and its trajectory was relatively consistent enough to calculate the landing point before firing?

Well, of course it would be. It’s ridiculously thick so the barrel can withstand the gunpowder explosion, and it’s absurdly heavy so once aimed, it won’t shake even when the gunpowder explodes.

“…! I-I’m sorry, Your Majesty.”

While I was shocked at the price and scale of that cannon, the craftsman beside me hastily apologizes as if terrified.

Was he flustered because I didn’t say anything?

“So… it’s bronze made of 360kg of copper and 36kg of tin, alloyed at a 10:1 ratio.”

“…Thank you.”

The craftsman, thinking I was angry because he had generalized it as just “bronze,” explains the alloy ratio in panic.

Tin… costs about five times more than copper, if I recall correctly?

Bronze found in nature would have inconsistent alloy ratios, making it unsuitable for military equipment that requires uniformity. That means they’d have to melt pure copper and tin separately to create the alloy. And naturally, all of this adds to the cost.

Add to that the gunpowder, cannonballs, and the price of wheels sturdy enough to support the barrel’s weight… um…

“…Hey.”

“Yes, Your Majesty.”

“How effective is that cannon at siege warfare? Since we can’t determine its power just by shooting at a pile of wood, I’d like to test it on a stone structure.”

Sigh… can’t be helped. For now, it’s better to produce the minimum and use them for sieges.

If its power is certain, even if expensive, making a few would be useful for siege warfare.

It didn’t look that big, but 400kg? Metal really is incredibly heavy for its volume.

“Um… Your Majesty, stone structures take time to build, so you’ll have to wait quite a while.”

The craftsman who heard my order fidgets nervously, then swallows hard as if making a decision and says this.

“Ah, I suppose that’s true.”

Indeed, a stone structure large enough to test the cannon’s power wouldn’t be built quickly. It would take at least a week.

Hmm… that’s too long, and I want to see results right away— I know.

“Isn’t there a stone structure right there?”

“Where do you mean, what—ugh…”

Sitting in my chair, I point and say this, and the craftsman follows my finger with a puzzled expression before seeing what I’m pointing at and is greatly shocked.

The city wall.

The wall of Dijon was right there.

“Y-Your Majesty…”

“Isn’t it an excellent target to test whether the cannon can destroy a wall or not? No, since it’s an actual wall, it would be more accurate to call this a real battle rather than a test.”

Of course, it’s not the wall protecting the city center, but an outer wall built to create a bottleneck for enemy forces. Firing at the wall protecting the city would just be insane.

But for the craftsman, such distinctions don’t seem necessary. After all, an outer wall is still a wall.

“That outer wall was going to be demolished anyway as it interferes with city development. Rather than just demolishing it, wouldn’t it be better to use it more productively?”

“Under…stood…”

Realizing he couldn’t dissuade me no matter what, the master craftsman nods dejectedly and orders his subordinates to drag the cannon in front of the wall.

The craftsmen who were scraping out gunpowder residue from the barrel are shocked, wondering if they heard correctly, but after looking back and forth between my nonchalant expression and their master’s closed eyes, they eventually nod with trembling heads.

What’s with you all? Why are you acting like this?

It seems like they’re having some major misunderstanding, but I can’t explain myself when they haven’t said anything—it would be beneath my dignity.

“…Do you have any questions?”

“None, Your Majesty.”

Unable to bear it, I directly ask if they have any questions to clear up the misunderstanding, but the craftsman hastily shakes his head, showing with his whole body that [I have no doubts about Your Majesty!]

No, don’t do that, just say it with words.

Your expression and actions reveal everything.

“…Very well then. Let’s return to discussing the cannon.”

Sigh.

There’s no point in pressing further as he won’t give a proper answer, so I decided to ignore it and get back to business.

It will take time to clean the muzzle, cool it down, and position the wall within firing range anyway.

“Can you reduce the materials used in that cannon? I don’t mind if the power decreases.”

“Ah, we’re currently researching that. We’ve made a prototype of a smaller 50kg cannon, but if we use less gunpowder, the power is mediocre and the trajectory unstable. If we use more gunpowder, the barrel explodes.”

Honestly, cannons made through casting shouldn’t have such dramatic performance differences. It’s probably an issue with the gunpowder, but that’s not something for the craftsmen here to handle, so I’ll pass on that for now.

“How much difference is there in caliber?”

“About 1.54 cubits… I apologize, the 50kg one has a caliber of 65mm, while the 400kg one is 120mm.”

65mm and 120mm.

Both calibers are reasonable.

The 50kg, or 65mm one, would be very useful in the field for destroying enemy fortifications and hastily constructed buildings. As for the 120mm one, if it’s good for sieges, we can’t make many, but we should keep a few. If it’s not good for sieges, we’ll have to discard it and only make the 65mm ones.

“Also, try researching making cannons with iron mixed in. Isn’t pure bronze too expensive?”

“…Your Majesty, we’ve tried making iron cannons many times, but they all exploded, resulting in casualties—”

“I know that from the reports. Cast iron is too brittle and inevitably develops air bubbles during casting, so it can’t withstand the explosive force of gunpowder. Iron also has a much higher melting point than bronze, making it harder to work with.”

“Y-Yes…?”

The craftsman’s eyes widen as I use technical blacksmithing terms. It seems quite surprising to him that a nobleman not only takes interest in such industrial matters but actually knows something meaningful about them.

I’m the one who ordered the creation of gunpowder and cannons in the first place and even made the blueprints, so why is he surprised now?

“So try making the barrel with different materials for the inner and outer diameters. For example, cover an inner diameter made of cast iron with an outer layer of copper or bronze.”

“…!”

I remember that the Hongyi cannon, a Ming dynasty version of the culverin, saved costs by using different materials for the inner and outer parts of the barrel. I don’t recall exactly what materials they used, but since the outer part needs to be less brittle than the inner part, they probably used copper or bronze.

“That… makes sense. We could pre-make the inner diameter with cast iron and then coat it with bronze or copper. As the outer bronze or copper cools quickly, it could compress the cast iron inner part… Yes, or perhaps wrought iron for the inner part and cast iron for the outer— Ahem. I apologize, Your Majesty. The idea of separating inner and outer diameters is excellent. However, it would require two separate processes, doubling the fuel needed and demanding very precise work. Moreover, iron isn’t particularly cheap and has a high melting point, so there might not be much cost benefit.”

The craftsman, seemingly impressed by my idea, mutters various thoughts to himself in a thought experiment, then suddenly remembers I’m present and quickly returns to reality.

Afterward, he realizes the meaning behind my suggestion to separate the inner and outer diameters and advises that it might not yield cost benefits. Precise work means reduced production, and doing the work twice with more fuel means increased costs, so ultimately there might not be much price difference compared to making it from pure bronze.

“As for precise work… well, you’ll just have to work hard on that, but you needn’t worry about fuel or melting iron.”

I can’t do much about the precision work. Good precision requires skilled technicians, and improving skills only comes with time and effort no matter how hard you try. What’s that saying… there’s no royal road? That’s exactly right.

But I can certainly solve the other issues.

*Swish*

“Your Majesty, please don’t touch that! It’s too dirty—”

“It’s fine, it’s fine. I can just wash up later. Is this charcoal?”

“Pardon…? Yes, it’s charcoal.”

The craftsman who was alarmed about me getting dirty answers my seemingly random question with an expression that says “isn’t that obvious?”

Charcoal… well, that makes sense. Natural coal is difficult to use for smelting.

“Have you tried using coal?”

“Coal… you say? It produces too much smoke, doesn’t get hot enough, and makes the iron rot, so we can’t use it.”

Produces a lot of smoke and makes iron rot… that means the coal mined around here has many impurities.

Good.

If it had been anthracite, things might have gotten complicated, but if it’s bituminous coal, we can make coke.