The Devil's Lamp
After the meeting adjourned, I headed straight to my private workshop, tucked away in a corner of the palace. The look of sheer horror on my vassals' faces during the meeting kept replaying in my mind, refusing to fade.
To hear that I was sending thirty thousand prisoners to the Silesian coal mines—they reacted as if I had personally thrown those thirty thousand people into a pit of molten lava.
'Buried alive? Give me a break.'
Of course, it wasn't that I didn't understand their reaction. In the Middle Ages—no, in the pre-modern era—a mine was a living hell, a place where you were lucky to walk out alive. But in my head, the blueprint to transform that hell into a cradle of industry was already complete.
Scritch, scritch, scritch.
The sound of a file biting into metal echoed rhythmically. I was engrossed in hammering a brass plate on the workbench and weaving thin copper wires into a dense mesh. My fingertips were stained black with metal dust, but I couldn't stop.
Just then, I felt a presence behind me.
Creak.
"My Lord, what are you making in here again?"
It was Janos. He hadn't been seen for a while after I left the meeting room, and it seemed his curiosity had finally gotten the better of him. He sniffed the air, eyeing the cluttered mess of metal parts, bundles of wire, and a leather pouch that emitted a peculiar stench on my workbench.
"I thought you might be sharpening cannonballs... but the smell is foul. What is this? A birdcage? Or a rat trap?"
"Something like that. A trap to cage fire instead of rats."
I tightened the final joint of the wire mesh and lifted the finished object. To the naked eye, it looked like a crude brass lamp. The only difference from a standard lamp was that the wick, where the flame would burn, was encased in a very fine metal mesh.
"What is this?"
"A Davy Lamp."
I shook the lamp and grinned. "A gift for the miners who will be leaving for Silesia."
"A... gift?"
Janos's expression twisted strangely. He looked as if he suspected I had built some sort of torture device. I clicked my tongue and set the lamp down on the workbench.
"Janos, why do you think mines are dangerous?"
"Well... because the tunnels collapse and you get crushed to death? Or you wither away from the exhaustion."
"Roof collapses are scary, of course. But there is something else the miners fear most. Something they commonly call 'the devil's fart.'"
It was Methane.
Trapped between coal seams is methane gas, generated by the decay of primeval plants. When a miner digs out coal with a pickaxe, this gas seeps into the tunnel. The problem is that it is invisible and odorless. In fact, after the meeting, I did some research... and the mining environment of the Middle Ages was a far more horrific hell than I had imagined. Modern mines are dangerous, but in this era, the very concept of safety didn't exist.
Carrying a torch into a gas-filled tunnel? That wasn't just a suicide mission; it was turning the entire mine into a giant bomb.
So, what did miners in this era do? They sent in 'penitents,' called Büsser, first. Under the condition of having their sins forgiven, they would force a prisoner to wrap themselves in wet rags, tie a candle to the end of a long pole, and crawl inside. If there was gas? BOOM! It would explode. Once that person burned to death and the gas was consumed, only then would the other miners enter.
'They call them penitents, but they're just human mine-clearers.'
Even the famous 'canary in a coal mine'—a trope known in modern times—wasn't widely used until the 19th century. Before that, they literally ground up human lives, risking everything to mine coal. With such barbaric methods, sending thirty thousand people would mean they’d all be dead in less than a month. It was unacceptable from a humanitarian standpoint, and a massive loss from an industrial one. A skilled miner isn't a disposable item to be used once and discarded; they are a valuable asset to the state.
"That is why I made this. With this lamp, you can light a fire in a gas-filled place without worrying about explosions."
Janos examined the lamp from every angle, still looking skeptical. "My Lord, the joke has gone too far. You expect to stop an explosion with just this thin piece of wire mesh? What good is this hole-riddled net?"
"Seeing is believing. Let's run an experiment."
I picked up a tightly inflated leather pouch I had left in the corner of the workbench. It was made from stitched animal bladders, incredibly durable and airtight. As soon as I picked it up, Janos frowned and pinched his nose.
"Ugh, My Lord. What is that? It’s been reeking of excrement since earlier."
"It's bovine gastric gas."
"Excuse me? Bovine... stomach?"
"Yes. I went to the slaughterhouse and collected it by inserting a tube into the stomach of a freshly killed cow. It's very fresh."
Cows produce a massive amount of methane gas through microbial fermentation in their stomachs while ruminating. The gas released when a cow burps is the exact same component as the methane gas in a mine tunnel. Janos recoiled in horror.
"My goodness, you’ve become a King, and now you’re collecting cow burps? Your tastes are truly unique."
"Quiet. This is the most reliable way to simulate the environment inside a mine. Close the curtains and turn off the lights."
Swish.
As Janos grumbled and pulled the heavy velvet curtains shut, extinguishing the candles, the room plunged into darkness. I struck a flint and lit the lamp's wick.
Sizzle, crackle.
A small flame bloomed inside the wire mesh. The light was somewhat soft, but it was enough to illuminate the pitch-black darkness.
"Watch closely. From now on, assume the place where this lamp sits is a mine filled with gas."
I brought the nozzle of the pouch containing the cow's stomach gas close to the wire mesh of the lamp. Then, I carefully squeezed the pouch.
Pssssssst.
Along with the sound of gas escaping, a foul odor spread instantly. With a normal lamp, the moment the flammable gas touched the flame, it would have gone POOF! and ignited, causing the pouch itself to explode. Janos must have expected that, as he flinched and squeezed his eyes shut.
But.
"...Huh?"
There was no explosion. Instead, a bizarre phenomenon occurred. The yellow flame burning inside the wire mesh surged upward the moment it met the gas, and the top of the flame turned a mystical blue. It flickered like a will-o'-the-wisp, but the blue flame remained tamely trapped within the wire mesh. Even though the gas continued to pour out, the fire did not spread outside the mesh.
"How... is this possible? The gas touched it, so why didn't it explode?"
"It's a simple principle of thermodynamics."
"Thermo... what?"
I set the pouch aside, picked up the lamp, and tapped the wire mesh part. "For a flame to burn, you need oxygen, fuel, and high temperatures. This dense copper wire mesh has very high thermal conductivity. The moment the flame inside tries to pass through the holes to get out, the cold metal mesh instantly strips away the heat of the flame."
This was the core principle of the Davy Lamp, invented in the 19th century by the British chemist Sir Humphry Davy. Just as hot broth cools down when strained, the flame cools as it passes through the mesh, preventing it from igniting the gas outside.
"Thanks to this, even if the gas burns inside the lamp, the fire doesn't spread outside. In other words, you can safely light a fire even in a gas-filled mine."
I thrust the lamp right in front of Janos's nose. "Besides, you saw it, right? It’s usually yellow, but it turns blue like this if there’s gas. It acts as a sort of alarm. If the color of the flame changes? Then you just run away immediately."
"Hah..."
Janos stared at the lamp with a dazed expression. A tool that allows one to enter deep tunnels without the risk of gas explosions. With just this, coal production could jump several times over. But my inventions didn't end there.
"And look at this, too."
I pulled out a pouch containing cloth and charcoal powder from the corner of the workbench. It was an object with crushed activated charcoal (charcoal) packed between several layers of cotton cloth, with strings attached to cover the nose and mouth.
"What is this now? Some kind of muzzle? Is it like a bit for a horse?"
"A mask. A dust mask."
I put the mask on myself. "When you work in a mine, you end up breathing in coal dust. If that accumulates in your lungs, you get a disease called pneumoconiosis. Every time you breathe, your lungs harden like stone, and you eventually die a painful death while coughing up blood."
"Ah, I think I've heard of that. They say miners catch lung disease so easily."
"That's why I'm going to make them wear this. If this charcoal filter screens out the fine dust, the number of people dying from the disease will decrease."
I took off the mask and placed it on the table. "And finally, I'm designing a ventilation system as well."
I pointed to the blueprint I had drawn on the chalkboard. "Instead of digging just one tunnel, I'll dig an entrance and an exit separately and connect them in a U-shape. And then, I'll light a fire at the bottom of the exit tunnel."
"A fire in the tunnel? Isn't that dangerous?"
"No, not at the entrance, but at the bottom of the vertical shaft at the exit. If you light a fire, the air will heat up and rise, right? It's convection. When the hot air escapes, fresh air is sucked in from the entrance to fill the void."
A natural air circulation pump. With just this, one could breathe as easily as on the surface, even hundreds of meters underground. In other words, it was an eco-friendly ventilation fan. I continued my explanation, excited. "This way, gas can escape quickly, and the temperature can be lowered. Since they can work in a comfortable environment, work efficiency will increase, and the number of miners dying from disease will decrease. How about it? Isn't it perfect?"
I looked at Janos with a proud expression. Protecting the miners' lives and increasing productivity. They were truly humanitarian inventions that killed two birds with one stone. If not a Nobel Peace Prize, wouldn't this at least be worthy of an International Labour Organization (ILO) commendation?
But Janos's expression was strange. It wasn't one of admiration or respect, but rather he was pale, as if he had encountered something indescribably terrifying.
"My Lord..."
"Why? Is there something you don't understand?"
"No. I don't know a thing about thermodynamics or convection, but I think I understand what you're saying. And that's why I'm even more terrified."
Janos stepped back and muttered, "So... you're going to make them crawl into places where people explode and die from gas, just to force them to mine coal..."
"Huh?"
"You're going to give them breathing room so they don't die within a year from suffocation, just so you can work them until their lungs harden—no, until they die of old age."
"No, wait a minute. That wasn't my intention..."
"That obsession to keep them alive until they pay off their ransom... it’s truly chilling."
Janos's eyes wavered. It was the look of someone seeing something that transcended humanity. "Not killing them, not letting them rest, but turning them into machines solely for labor... it’s an idea that would make even the devil weep. I dare not follow the abyss-like cruelty of my Lord."
"..."
No, I just wanted them to work safely... because I hated seeing people die...
"What did you say the name of this invention was?"
"Davy Lamp."
Janos nodded and murmured under his breath, "Yes, Devil Lamp."
"It's Davy."
"An evil lamp that lights the fires of hell so miners can work without a moment's rest... you’ve named it quite brilliantly. I will have these lamps sent to the blacksmith immediately for mass production."
"...Fine, do as you please."
I gave up on explaining. Just as Janos was about to leave the workshop with the lamp, I remembered something and stopped him for a moment.
"Ah, Janos. On your way out, call someone for me."
"Who, My Lord?"
"Priest Jan Zelivsky."
The most radical Taborite agitator in Prague. When that name came up, Janos hesitated, looking puzzled. "Why are you suddenly looking for that fiery man?"
I tapped my fingers on the empty workbench and answered nonchalantly, "The thirty thousand prisoners are all Catholics who follow the Pope to the bone. Just shoving them into a mine isn't the end of it. They'll be clutching their crosses and plotting riots at every opportunity."
The Silesian mines would imprison their bodies, but imprisoning their minds was a different matter. I had to dig out the Roman Catholicism embedded in their heads and install new software before I could safely put them to work. Whether they returned home after regaining their freedom or wished to become subjects of Bohemia later, it didn't matter.
A cold smile spread across my lips. "Go and tell him. Tell him there are thirty thousand lost lambs waiting for him to save them."