Chapter 97: The Spark of Induction

Klein’s question rippled through Lia’s composure, leaving her mind anything but calm.

‘Could moving magnetism generate electricity?’

This question, simple as it seemed, touched upon a crucial cornerstone of electromagnetism, a field she knew well from her previous life.

Lia lifted her gaze, meeting Klein’s probing blue eyes directly.

Swiftly, she composed herself, once again deploying the familiar shield she’d used during her rather uncomfortable ‘interview’.

“Perhaps… it’s possible.”

Lia’s voice was laced with uncertainty as she lowered her eyelids, adopting the posture of someone deep in thought, sifting through distant memories.

“I recall that at the very end of an ancient tome, the author left behind a rather ambiguous conjecture.”

“He posited that electricity and magnetism were two facets of the same fundamental force in the world. If flowing electricity could exhibit magnetic properties, then, conversely, a changing magnetic field should logically be capable of igniting the spark of electricity.”

Lia paused, then added, “Yet, this was ultimately nothing more than a conjecture, a mere assertion devoid of any experimental evidence. It seemed the ancient sage himself found the idea too revolutionary, and thus refrained from exploring it further.”

Klein listened in silence, not pressing for any further details regarding the ancient text.

He gazed deeply at Lia, his eyes alight with a fervent spark that Lia could not quite decipher.

“A mere conjecture…”

He murmured, then turned away.

“But since it comes from you, that is enough.”

Lia watched him vanish around the bend of the staircase, releasing a silent sigh of relief.

‘Thankfully, I managed to bluff my way through again.’

Lia mused internally, but Klein’s parting words—”But since it comes from you, that is enough”—left her thoughts in disarray.

The emphasis of his statement wasn’t on the ‘ancient tome,’ but on ‘you.’

‘He wasn’t placing his trust in some ethereal conjecture from an ancient sage, but in me?’

Lia’s brow furrowed almost imperceptibly.

***

Having concluded his conversation with Lia, Klein returned to his chambers, making his way directly to a row of bookshelves nestled in the deepest part of the room.

He extended a hand, gently pressing upon an unassuming spell theory book located on the third shelf.

The entire bookshelf glided silently to one side, revealing a hidden door crafted from dark ebony.

Beyond the door lay a space entirely unlike the room it concealed.

The air within was thick with the distinctive scent of metal, oil, and aged parchment, a unique blend that spoke of forgotten knowledge and tireless work.

Dozens of magical arrays, varying in size, were etched into the floor and walls, connected by intricate silver lines that formed a vast and complex system.

In the corners of the room, an assortment of peculiar metal components, coils, magnets, and glass instruments lay piled high.

This was Klein’s clandestine sanctuary, a repository for his most cherished memories.

He approached a desk positioned at the room’s center, and from its lowest drawer, carefully retrieved a wooden box, safeguarded by a magical seal.

Breaking the seal, he opened the box.

Within, nestled a worn, aged notebook, its cover faded with time.

He extended a finger, his thumb gently caressing the notebook’s cover, his gaze growing distant, lost in memory.

This was his mentor’s notebook.

The notebook of his predecessor.

It contained no systematically organized theories, only the boundless, fragmented conjectures of his teacher.

Even if this notebook were to be handed over, it would be of no use in resolving the ‘Wrath of the Sun’ crisis.

Thus, driven by a personal impulse, he had kept it for himself.

Klein opened the notebook, and the familiar script immediately caught his eye.

“…Why does the force of a magnet penetrate wood? What role does aether play in this phenomenon?”

“…The essence of lightning is flowing electrical charge; it generates heat and light, and perhaps, something more, something we have yet to observe…”

“…I attempted to rapidly spin a magnet, yet failed to detect any trace of electricity. Was my method flawed, or did this connection simply not exist?”

Klein closed the notebook, his chest rising and falling imperceptibly.

‘Master, what you lacked was not the key itself, but the eyes to perceive the keyhole.’

‘And now, Lia has gifted this world with those very eyes.’

***

In the days that followed, Klein immersed himself in his own research.

He instructed Adèle to inform Lia that she was free to arrange her time as she pleased, attending any courses at the academy that piqued her interest, rather than remaining confined to the Mage Tower.

Though a touch puzzled, Lia nonetheless happily made her way to the academy.

Within the Mage Tower, Klein meticulously studied every paper submitted by Lia and her peers, repeating their experimental procedures no less than ten times.

Now, standing upon the shoulders of giants, he was poised to gaze into the distant horizon.

He constructed a micro-ammeter even more sensitive than Michael Faraday’s, its delicate pointer tipped with a minuscule piece of fluorescent material.

Even the faintest deflection caused by the most minute current would not escape his keen observation.

He wound a bundle of copper wire into a coil, connecting its two ends to the micro-ammeter.

Then, grasping a bar magnet, he drew a deep breath.

And with a sudden, decisive motion, he plunged it into the coil!

In that instant, the micro-ammeter’s slender needle abruptly flickered to the right, deviating by a minuscule angle!

The needle swiftly returned to its original position, as if nothing had occurred.

Yet, Klein’s breath hitched in his throat.

He had witnessed it!

The very phenomenon his revered mentor had sought his entire life, yet never attained, was now unfolding before his eyes!

Suppressing the tumultuous surge within him, he withdrew the magnet from the coil.

The needle, once again, deflected!

This time, it veered in the opposite direction!

A brilliant light ignited in Klein’s eyes.

He embarked on a frenzy of experimentation.

Rapid insertions, slow insertions; swift withdrawals, gradual withdrawals.

He discovered that the faster the magnet moved, the greater the angle of the needle’s deflection, and consequently, the stronger the induced current.

Conversely, when the magnet remained stationary within the coil, regardless of its magnetic strength, no current whatsoever was produced.

It was exactly as Lia had posited!

Not simply magnetism.

It was *moving* magnetism!

It was *changing* magnetism!

For half a month, Klein remained engrossed in these qualitative experiments.

He meticulously verified every conceivable scenario.

He found that by keeping the magnet stationary and moving the coil instead, he could similarly generate an electric current.

He had succeeded; he had unequivocally validated his mentor’s conjecture: magnetism could, indeed, generate electricity.

Yet, Klein was far from satisfied.

Merely understanding that it ‘could’ happen was woefully insufficient.

How was this any different from the mages of old, who simply recited incantations without comprehension?

He sought to uncover the underlying laws, to discover the quantifiable, elegantly simple rules that governed this phenomenon.

Another half-month elapsed.

Outside his window, the eerie orange-red hue that had lingered for months, a grim consequence of the ‘Wrath of the Sun,’ had begun to recede, gradually revealing the sky’s inherent azure.

Communication crystals across the Royal Capital, too, began to sporadically flicker back to functionality.

The entire world was slowly, painstakingly, recovering from a catastrophic ordeal.

Meanwhile, Klein’s own experiments had advanced to a crucial stage.

He needed to quantify three distinct elements: the ‘magnitude’ of the magnetic field, the rate at which this magnitude changed, and the ‘driving force’ of the resulting current.

Initially, he struggled with how to quantify the magnetic field itself.

He attempted to correlate the strength of the induced current with the magnetic field intensity proposed by Michael Faraday, but the resulting data proved chaotic and inconsistent.

Next, he tried to link the current to the coil’s surface area, but this approach yielded similarly erratic results.

For an entire week, he remained ensnared by this conundrum; no matter how he swapped magnets or altered coil dimensions, a stable correlation remained elusive.

One late night, he leaned back, utterly exhausted, in his chair, his gaze drifting over the various coils scattered across his desk.

A sudden thought pierced through his fatigue: ‘When rainwater falls into a bucket, the amount of water it catches depends not only on how heavy the rain is (intensity) but also on the size of the bucket’s opening (area).’

‘Perhaps what I need to measure isn’t the magnetic field strength at a single point, but rather the ‘total magnetic field’ passing through the entire coil circuit!’

With a surge of excitement, he seized his pen and, by multiplying magnetic field strength with the coil’s area, conceived a wholly new physical quantity, which he christened ‘magnetic flux.’

When he incorporated this novel concept into his data, a clear and undeniable pattern finally materialized from the chaotic haze of numbers.

As for the driving force of the current, he eschewed the conventional concept of voltage, instead naming it ‘induced electromotive force.’

This term represented the electrical potential energy that could be generated by this inductive phenomenon, with the concept of potential energy itself drawing inspiration from the latter half of Lia’s groundbreaking paper on gravity.

The most formidable challenge lay in accurately measuring the ‘rate of change.’

After enduring countless setbacks, he devised an ingenious apparatus. He engineered a massive circular disk to rotate at a constant velocity, its speed precisely controlled by magic, allowing the coil to cut through the magnetic field lines produced by the disk at various points.

Through a vast accumulation of data recording and meticulous analysis, he finally unearthed the elusive law he had so desperately sought.

The magnitude of the induced electromotive force was directly proportional to the rate of change of magnetic flux passing through the closed circuit!

The more rapidly the magnetic flux changed, the greater the electromotive force generated!

Yet, just as he believed he had finally grasped the hem of truth, a new and perplexing challenge materialized before him.

Direction.

What precise law governed the direction of the induced current?

Reviewing his experimental logs, he uncovered a perplexing phenomenon: the direction of the induced current seemed utterly capricious.

When he inserted the north pole of the magnet into the coil, the ammeter’s needle would deflect in one direction; however, when he inserted the south pole, the needle would veer in the exact opposite direction.

Upon withdrawing the magnet, the direction of deflection would reverse once more.

“Why?” Klein murmured to himself.

He initially suspected his micro-ammeter was malfunctioning.

After ruling out all possibilities of instrument failure, he re-examined his data, striving to uncover the logic behind this ‘temperamental’ direction.

He categorized all instances of ‘increasing magnetic flux’ into one group and ‘decreasing magnetic flux’ into another, utilizing a technique developed by a lightning mage—or rather, an electromagnetic mage, as they were now known.

The said mage had, through their research, discovered the Right-Hand Screw Rule, which determined the direction of the magnetic field produced by an induced current, a paper Klein had also read.

Applying the Right-Hand Screw Rule, he was able to ascertain the direction of the magnetic field generated by the induced current in each scenario.

The pattern, at this moment, became strikingly clear.

When the magnet approached, and magnetic flux increased, the magnetic field generated by the induced current consistently repelled it; conversely, when the magnet moved away, and magnetic flux decreased, the magnetic field generated by the induced current consistently attracted it.

It always resisted!

Regardless of whether the magnetic flux was increasing or decreasing, the magnetic field produced by the induced current always opposed that change!

This discovery sent a shiver of profound insight through Klein’s very soul.

He picked up his quill, and on a fresh sheet of parchment, he inscribed the law that governed the generation of electricity from magnetism.

“The magnitude of the induced electromotive force in a closed circuit is equal to the rate of change of magnetic flux through that circuit.”

“The induced current will flow in such a direction that the magnetic field it produces always opposes the change in magnetic flux that caused it.”

Two months of relentless research, countless sleepless nights, his mentor’s lifelong ambition, and the era Lia had ushered in—all converged at this moment, crystallizing into these two concise yet profound descriptions.

Klein leaned back in his chair, exhaling a long, weary breath.

Fatigue emanated from the depths of his spirit, yet his mind felt clearer than ever before.

He had done it.

For himself, and for his teacher, he had found the magnificent bridge connecting magnetism and electricity.

He lifted his gaze to the window.

On the horizon, the last vestiges of the orange-red sunset were fading, and a brilliant star quietly ascended into the azure night sky.

One era had ended.

And he, Klein, would personally participate in the next.

Klein straightened in his chair, unfurled a pristine sheet of parchment, and dipped his quill deeply into the ink.

His pen hovered above the paper, his eyes gleaming with confidence and pride.

Moments later, a title potent enough to once again shake the entire magical world was solemnly inscribed at the very top of the parchment.

‘On the Fundamental Laws of Magnetic Induction of Electricity.’