Electromagnetism in the Middle Ages

To produce electric current, one had to understand electromagnetism. In modern Earth history, on October 17, 1831, Faraday first discovered electromagnetic induction and subsequently found a way to generate alternating current, a major achievement in electromagnetism.

The so-called phenomenon of electromagnetic induction was when a magnet passed through a closed circuit, causing an electric current to arise within the circuit.

By making use of this phenomenon, keeping the closed circuit stationary while continuously rotating the magnet, the stationary circuit would cut through the magnetic field lines emitted by the magnet, continuously generating electric current. Mechanical energy would be converted into electrical energy, creating a simple generator. This was high school physics textbook knowledge, nothing particularly profound, though the troublesome part was obtaining the basic materials and components.

To keep this generator running continuously, human labor would not do. It was inefficient and prone to mistakes, so natural resources had to be used—either wind power or water power. Richard chose wind power and thus designed a power-generating windmill for the craftsmen to make.

However, the craftsmen could only make some simple parts. Complex components such as the rotor, energy storage device, and rotating shaft had to be made personally, which was quite troublesome. That was precisely why he did not want to do this unless absolutely necessary.

But since he had decided, he could only keep going.

First came the construction of the rotor.

The rotor's main material was magnets. Neodymium Iron Boron Magnets, Samarium Cobalt Magnets, Alnico Magnets, and Iron Chromium Cobalt Magnets would all work. But in the current world, within the Blue Lion Kingdom, there were no magnets of any kind at all, so he could only make them himself. The type he chose to produce was the simplest and most common kind—Tetrairon Trioxide (Fe3O4) magnets.

To make Tetrairon Trioxide magnets, he first needed to obtain Tetrairon Trioxide itself.

There were many ways to obtain this material, such as the Hydrogen Reduction Method of α-Iron Oxide, the Slow Oxidation Method of Ferrous Hydroxide, the Harber Method, the Combination Method, the Alkali Addition Method, and so on. He chose the Combination Method. The two most crucial reactant substrates for this method were elemental iron—iron filings, Fe—and Iron Oxide—rust powder, Fe2O3...

...Taking a deep breath, Richard washed his hands, put on a dust mask to prevent powder from entering his mouth and nose, and began working.

First, Richard placed the iron filings into Sulfuric Acid. The moment they went in, the beaker visibly produced a large number of bubbles as a violent reaction began. During this process, Ferrous Sulfate (FeSO4) would be produced.

Once the reaction was complete, Richard added Caustic Soda (NaOH) and Iron Oxide (Fe2O3). He then heated the mixture to 95–105°C, allowing a combination reaction to occur in the solution and ultimately produce Tetrairon Trioxide.

However, the Tetrairon Trioxide was not pure at this point. Richard transferred the solution into a funnel fitted with filter paper and began filtering it. Afterward, he dried the filtered solid material, then carried out a series of further operations. After considerable effort, he finally produced pure Tetrairon Trioxide.

After magnetization, the Tetrairon Trioxide became real magnets, black as ink. Repeating this process, he made enough magnets and fixed them inside a circular mold, completing the most important component of the generator—the rotor. After finishing this, Richard did not rest. He began making an energy storage device. After all, the windmill could generate electricity, but the electricity had to be stored before it could be used. This required a real rechargeable battery, not a fruit battery, much less a capacitor like a Leyden Jar.

Richard planned to make a Lead-Acid Battery, the cheapest and most common electric vehicle battery on modern Earth.

He chose it because the materials were easy to gather on one hand, and because its structure was simple on the other. It consisted of only four parts: a positive plate group, a negative plate group, electrolyte, and a container.

Other than the Sulfuric Acid used as the electrolyte, only one substance—or rather, two substances—were needed:

The first was lead, used to make the negative plate group.

The second was lead's oxide in air, Lead Oxide, used to make the positive plate group.

This current world of the Middle Ages might lack many things, but it could never lack lead. According to modern Earth's development, humanity had already begun extracting large quantities of iron, copper, silver, and lead more than two thousand years ago.

Thus, without much effort, Richard had people acquire enough lead and Lead Oxide.

Taking a deep breath, Richard's expression grew somewhat grave.

Both lead and Lead Oxide were toxic. Excessive inhalation or ingestion could cause heavy metal poisoning, resulting in physical discomfort at best and death at worst.

During Ancient Rome on modern Earth, the Romans did not know of lead's dangers. They used lead pipes for water transportation over long periods and used lead vessels for drinking alcohol, resulting in chronic lead poisoning among a great number of people. This became an important reason for Ancient Rome's decline.

Richard knew this and did not want to repeat the same mistakes. He did not want to become gravely ill before even becoming a Wizard, so he made thorough preparations before conducting the experiment.

First, he put on a dust mask, then wore a Beak Mask over it. He changed into a tight black protective suit that covered every inch of skin, and finally put on gloves made from cow bladders.

Once he was ready, Richard took a deep breath, feeling the air pass through the pouch of herbs in the Beak Mask and fill his lungs. His gaze steadied, and he got to work.

First, he poured enough Sulfuric Acid into the prepared container as the electrolyte. Then he inserted the gray, velvety lead plates that would serve as the negative electrodes and secured them in place. Next, he inserted the brown Lead Oxide plates that would serve as the positive electrodes and secured them as well.

Between the positive and negative electrodes, he placed separator plates to prevent the electrodes from touching. After that, he repeated the process, continuously inserting one lead plate followed by one Lead Oxide plate into the container until the entire container was packed full.

The reason for doing this was to place multiple sets of positive and negative plates together in series, thereby increasing the voltage of the Lead-Acid Battery.

After finishing this, Richard let out a slight breath of relief. He knew that the main work on the Lead-Acid Battery was complete. What remained were trivial details, such as setting up the external wires.

Working bit by bit until evening, Richard finally finished everything.

With two soft bangs, Richard placed the completed Lead-Acid Battery and rotor onto a wooden rack. He turned around, removed his gloves, took off the Beak Mask, removed the dust mask, and stripped off his protective suit. Only then did he realize that he was soaked through.

After all, it was a hot summer day. Even inside the relatively cool palace, working for an entire afternoon had been exceedingly miserable. He had not noticed while he was working, but once he was done, Richard could feel his underclothes clinging to his skin, leaving his entire body unbearably sticky.

Frowning, Richard pushed open the door and walked out of the Independent Laboratory.