Magnesium Firestorm
Once the generator was developed following the steam engine, Yi Yeon decided to begin full-scale production of essential chemical compounds using electricity.
One of them was magnesium.
Until now, they had been grinding dolomite into powder, reacting it with hydrochloric acid to produce magnesium, and putting it to use. But manufacturing it was no simple task. Mass production had been impossible.
After reacting it with sodium hydroxide following the hydrochloric acid to obtain magnesium hydroxide, the mixture still required filtration and drying. Only after that could high-temperature thermal decomposition yield magnesium—and even then, it was riddled with impurities.
In contrast, using electricity drastically reduced the production process. It allowed them to obtain high-purity magnesium easily and quickly. Dolomite was no longer necessary.
By adding slaked lime (calcium hydroxide) to seawater to produce magnesium chloride, then dissolving it in water and performing electrolysis at 3.8 volts, the result was simple:
Cathode: Mg²⁺ + 2e⁻ → Mg (magnesium metal precipitates)
Anode: 2Cl⁻ → Cl₂ + 2e⁻ (chlorine gas is generated)
In this way, magnesium could be mass-produced with surprising ease. Moreover, the chlorine gas that evaporated was bubbled through water to produce hydrochloric acid—one of the three major strong acids—in bulk as well.
With the magnesium obtained this way, Yi Yeon created flares.
But magnesium burned up in an instant. To solve this problem, he mixed potassium chlorate with starch blended with sugar to create an oxidizer that would burn for a long time, then coated the surface with magnesium powder.
He also fashioned small parachutes from thin silk so they would automatically deploy and descend slowly.
The flares produced this way performed far better than expected. Even after hitting the ground, they continued burning for quite a while.
Using the same principle, he developed yonghwa-tan—Dragon Breath ammunition—that could be loaded into multi-barrel guns and spew flames.
Staring at the bright flames drifting slowly down from the sky, Samseongi shouted loudly.
But no answer came.
When he turned his head, he saw Chunsik—who had been responding to the enemy's relentless assaults for two straight days—fast asleep and snoring, exhausted.
Samseongi kicked the soundly sleeping Chunsik awake, then opened the ammunition box and pulled out a belt.
Startled awake, Chunsik bolted upright.
Chunsik lowered his body and peered down the slope. Then he sucked in a sharp breath.
The situation was completely different from the attacks so far. Instead of sporadic strikes at one or two points, the enemy was surging forward like a tidal wave, filling the entire wide plain.
There were so many of them that Chunsik felt the hairs on his entire body stand on end.
Samseongi opened the top cover of the machine gun, inserted the ammunition belt, closed it, pulled back the bolt, and pushed it forward again.
Snapping back to his senses, Chunsik held the belt steady so it wouldn't tangle. Samseongi aimed the muzzle at the enemy and pulled the trigger.
Then—
The machine gun shook violently like it had gone insane, spitting out bullets that tore through the enemy like ripping silk.
It was over in an instant. The ammunition box that had held a hundred rounds was already empty.
Chunsik hurriedly brought over another box, opened it, pulled out a fresh belt, and loaded the machine gun as he asked,
Once the precision lathe powered by the steam engine was completed, Yi Yeon had decided to start by building machine guns.
Originally, after the rolling block sniper rifle he had named the Eulsik rifle, he had planned to mass-produce and distribute the Henry rifle, which loaded rounds from the top.
The technology in the Henry rifle was necessary to transition to the lever-action repeating Winchester M1866.
But he changed his mind.
The nightmare caused by the matchlock guns had been too horrifying, and he judged that nothing overcame that terror better than a machine gun.
From that day on, Yi Yeon wracked his memory and designed something similar to the MG42—which Hitler had called “Hitler’s buzzsaw”—and the MG3, then handed the blueprints to Kim Ji with orders to develop it.
Since it was the gun Stephen had loved most, they had played with it together many times, so he knew its structure well.
He had considered making the Gatling gun—the world’s first machine gun—or the Maxim—the world’s first fully automatic machine gun—but gave up on both.
He understood the principles, but since he had never disassembled or used one, he couldn’t even begin to imagine how to build them.
Besides, he believed the weapons of the Hwaryeokgun, whose purpose was attack, needed to be light enough to carry. So he completely discarded the idea of building a Gatling or Maxim, both far more complicated and vastly heavier than the MG3.
In any case, the MG3 was the best.
Unlike the Maxim machine gun that weighed over sixty kilograms, the MG3 weighed less than twelve. It had far fewer parts. The barrel could be swapped quickly and easily. Its open-bolt design meant fewer malfunctions and easier repairs.
The only problem was that once the trigger was pulled, it would keep firing until the belt ran out. They had installed a safety on the trigger, but to reduce the risk of accidents, he had ordered that ammunition belts not be loaded during normal times.
However, there had been a problem during production. The MG3 was made by stamping thick steel plates with a power press, but neither wind power nor water power could generate that much force.
Fortunately, that issue was resolved once Yi I created a highly efficient steam engine.
But durability remained a concern. Although they were producing barrels and bolt assemblies from hard, heat-resistant manganese alloy steel, they hadn’t tested it thoroughly enough to know how it would hold up. So he issued instructions to change the barrel after every five hundred rounds.
The MG42 could fire over 1,200 rounds per minute, but the MG3 did not. They had deliberately made the bolt assembly heavier and the recoil spring weaker because wasting ammunition at that rate was excessive. As a result, the machine gun Samseongi was firing spat out about six hundred rounds per minute.
Even so, it was more than enough to sweep away the swarming enemy.
Firing from a height of over two hundred meters toward what was essentially a flat plain, the enemy fell without even having time to scream.
Samseongi pulled the trigger in short, controlled bursts as he had been taught, raking the areas where the enemy was clustered.
Chunsik held the belt steady so it wouldn’t jam. At first he had simply sprayed wildly in shock, but he no longer did that.
When the flare dimmed or went out, he waited. Only when a new flare rose and illuminated the field did he pick his targets and pull the trigger.
Thanks to that, no enemies reached their position. Or rather, they couldn’t.
Not only was the time needed to swap belts and barrels short, but the coiled barbed wire installed in front was blocking the enemy’s advance.
Thanks to the machine guns positioned at one-hundred-meter intervals, the vast plain gradually became covered in enemy corpses.
Yet the enemy numbers showed no sign of decreasing. As if they had resolved to die, they kept pouring forward.
Chunsik swallowed hard, clearly frightened, and out of habit opened another ammunition box, pulled out a belt, loaded it, and swapped the barrel.
Fortunately, they still had many of the ammunition boxes they had been issued. This time they had received a total of five thousand rounds of machine gun ammunition.
Once they began using the steam engine, bullet production had skyrocketed. Previously, producing even a thousand rounds a day had been difficult. Now they could easily churn out thirty thousand per day.
Thanks to that, they could supply ammunition in abundance. Samseongi, well-stocked with plenty of rounds, fired without restraint.
Samseongi and Chunsik supported each other, not only defending their own sector but also providing covering fire for other areas that were being pushed back.
But that didn’t last long.
The enemies who had reached the foot of the mountain were now hiding behind dirt mounds and tree roots, firing matchlocks and pressing the attack.
They could have cut down all the trees, but they couldn’t touch the roots. Flattening the uneven mountain slope had been impossible. The enemy was using that cover to creep closer little by little.
As a result, the number of wasted bullets began to rise sharply compared to those that actually hit. Moreover, more and more of the enemy’s bullets were thudding into the dirt-filled barricades with a dull thwack.
It looked like they might be overrun.
Flares rising high into the sky at regular intervals blazed so brightly that the entire area was lit up like daytime. The sounds of machine guns and multi-barrel guns rang out everywhere, yet it seemed impossible to stop the assault of hundreds of thousands of enemies.
At Chunsik’s startled cry, Samseongi turned to look where he was pointing. Enemies armed with swords, spears, and matchlocks appeared to have nearly reached the barricades their allies had set up.
The machine gun stationed there must have jammed, or perhaps the gunner had been hit.
But then—
A tremendous explosion hurled the enemies—who had been charging over their fallen comrades—backward in a spray of dirt and dust.
That wasn’t all. They must have switched to yonghwa-tan. Jets of flame over twenty meters long shot out in every direction. At the same time, grenades packed with oxidizer flew down the slope with sharp pop-pop sounds and detonated.
Explosions thundered across the slope as massive flames roared upward.
The entire area had become a sea of fire. When the grenades detonated, the magnesium inside ignited instantly. The oxidizer burned fiercely, incinerating everything around it.
The momentum of the enemies—who had charged forward without so much as blinking when their comrades fell—vanished in an instant. Those whose bodies were engulfed in flames began to flee, screaming in agony so horrible it chilled the blood.
That only caused an even greater disaster. The enemies tangled with the rear ranks—who were carrying iron-and-wood shields—were set ablaze together. Thanks to the flames, the enemy was now clearly visible even without flares.
Samseongi raked the moving flames with the machine gun. The entire mountainside was wrapped in roaring fire and smoke, making it hard to distinguish individual targets. But the effect was undeniable. The number of moving flames was steadily decreasing.
At that moment, a voice shouting through the ringing in his ears reached him.
A messenger holding a speaking trumpet ran back and forth, shouting at the top of his lungs. Yet the sound of gunfire continued for quite some time. Even though they had stuffed their ears with rolled cotton cloth, the continuous deafening explosions seemed to have damaged their hearing.
Yi Yeon had received the report that the enemy was approaching and climbed to the command post prepared at the summit of Mount Ushida.
Jeong Yeo-lip, who had been watching beside him, asked,
Yi Yeon rose from his seat and slowly surveyed the surroundings. Every direction surrounding their encampment was engulfed in flames.
Because they had flares and machine guns modeled after the MG3, he had boldly pushed forward with this operation. Even though failure could have meant the ruin of Joseon.
Fortunately, it seemed the operation had succeeded. Unexpectedly, the grenades packed with oxidizer had done the job.
I’ll have to develop flamethrowers as well.
After watching today’s battle, he finally understood why the British troops armed with Henry rifles during the Zulu War had been pushed back by Zulus wielding muskets.
So the saying “there is no defense against a dogpile” really is true.
They had nearly been overrun. It hadn’t even been a hundred-to-one fight—it had looked closer to thirty-to-one.
That was why Yi Yeon decided to develop flamethrowers. He had never even considered it before, thinking the weapon was too dangerous to allies if misused and far too cruel.
Yi Yeon’s eyes widened as he looked south.
What was unusual in this war was the situation in the south, where the Joseon Eastern Army was stationed. Until now, the enemy had never once attacked that direction. Even though they should have been far easier to deal with than the firearm-equipped Joseon troops.
But this time had been different. It seemed a large force had surged toward that area as well. Whether they had suffered a massive bombardment or not, a long horizontal line of flames stretched across the south, more than a kilometer away from the Joseon Eastern Army’s position.
With precision bombardment at that level, it looked like they might not even need to build flamethrowers.