Only then did Song Yingxing fully understand.
His own writings were meant to serve as practical textbooks, firmly rooted in the present. Meanwhile, Dao Xuan Tianzun's Heavenly Books pointed toward the future, illuminating paths not yet walked.
"So that is the distinction," Song Yingxing murmured, enlightenment settling over him like dawn light.
Li Daoxuan casually flipped to the final section of Tiangong Kaiwu, the newly added chapter that recorded the marvels of Gao Family Village in careful detail. Steam engines. Electric lamps. The latest mechanical refinements. All of it was cataloged meticulously.
He tapped the page with a faint smile. "I look forward to your next new chapter."
Song Yingxing's heart trembled. A next chapter. Of course there would be a next chapter. Innovation had not stopped.
At that moment, a sudden commotion erupted outside the bookstore.
A young man burst through the entrance, breathing hard, eyes scanning wildly. "Teacher Song! Is Teacher Song here? I heard you were at the bookstore, so I came immediately!"
Li Daoxuan glanced over and instantly recognized him.
This was the graduate student whose hot air balloon experiment had once drifted straight into a young woman's chamber, producing a romantic conclusion that could only be described as destiny in action. Li Daoxuan could not quite recall the young man's name, but he distinctly remembered his wife, Hou Lan, one of the women rescued at Houjia Village alongside Zhang Fengyi of the White Pole Soldiers.
The student rushed inside and only then noticed Dao Xuan Tianzun and Gao Yiye standing there.
He nearly jumped out of his skin.
Dropping into a deep bow, he spoke rapidly, "Greetings, Dao Xuan Tianzun. Greetings, Saintess."
Li Daoxuan chuckled. "What matter compels you to seek Mr. Song with such urgency?"
Song Yingxing stepped forward. "Yes, what is it?"
The young man brightened at once. "Teacher, I have been studying the propeller at the rear of the Celestial Ship bestowed by Dao Xuan Tianzun."
Li Daoxuan's interest sharpened. "Oh? And what conclusions have you reached?"
The student replied eagerly, "The propeller rotates and pushes water backward, which in turn propels the ship forward. After much thought, I realized the same principle should apply to air. So I conducted repeated experiments and designed a set of fan blades capable of continuously generating wind. If connected to a steam engine, turning like the Celestial Ship's propeller, it could produce an enormous gust of wind."
Li Daoxuan almost laughed aloud.
He has reinvented the electric fan.
Song Yingxing gave the young man an approving nod. "Excellent thinking. Truly excellent."
However, the student's expression darkened. "But there is a serious flaw. The steam engine is far too large. It burns coal, emits smoke, and roars like a beast. Using such a massive machine to power a small fan feels… disproportionate. Teacher, I hoped you might offer guidance. Is there another method?"
Song Yingxing fell silent.
The problem was obvious. The solution was not.
Li Daoxuan spoke calmly. "You have studied the power systems of the ships I provided, have you not?"
Song Yingxing immediately cupped his hands respectfully. "Indeed, Dao Xuan Tianzun. At first, we believed the Celestial Ships were driven by divine force. But through study, we discovered their power source is electricity. The solar panels bestowed by the Lord of the Sun Star convert sunlight into electricity, which then drives the propellers. This is as far as our research has progressed."
Li Daoxuan nodded. "Have you investigated how electricity causes the propeller to rotate?"
Song Yingxing hesitated. "The Celestial Ship is a sacred object. We dared not dismantle it."
Li Daoxuan smiled. "Electricity drives rotation through something called an electric motor. I will provide you with one. Dismantle it. Study it thoroughly. Once you understand its principles, you may use electricity to power Mo Li's fan directly from the village's electrical grid."
Gao Family Village already possessed a power grid. Since Li Daoxuan had provided large solar panels, the villagers had steadily constructed a network of wires throughout the settlement. Drawing upon the knowledge in their Middle School Physics and High School Physics textbooks, they had installed switches, designed circuits, and even invented electrical plugs. With Ji Menghan's development of the electric lamp, the village now shone brilliantly each evening. When the lights flicked on at dusk, it was a spectacle that left newcomers speechless.
Yet electricity had only begun to reveal its potential.
Li Daoxuan produced a small electric motor, the sort commonly used in children's toys and powered by miniature batteries, and placed it gently before the research building of Thirty Two Middle School.
To him it was tiny.
To the villagers, it was a massive construct several times their body length and taller than most of them.
Half an hour later, a crowd had gathered.
Song Yingxing stood at the front. Around him clustered graduate students, craftsmen, and curious onlookers.
"So this," someone whispered reverently, "is the true power mechanism of the Celestial Ship."
"It is enormous."
"Of course it is enormous. The Celestial Ship is vast. It must rely on something equally grand."
"What now?"
"We dismantle it."
Diagrams were unrolled. Tools were fetched.
Then came the first obstacle.
"There is a screw here. It requires an extremely large screwdriver."
They did not possess such a tool.
Fortunately, this was Gao Family Village.
An invisible force descended.
Though Dao Xuan Tianzun's hand was unseen, a colossal screwdriver appeared to move of its own accord, engaging the massive screw. It turned steadily. Once. Twice. Again.
With a sharp metallic snap, the screw came loose.
Cheers erupted.
"Dao Xuan Tianzun is assisting us!"
Piece by piece, the motor was dismantled. Its casing removed. Its internal components laid out carefully.
Soon, what had once been a single mysterious machine became a neat array of parts.
Song Yingxing led the examination.
"Look here. Coils. Copper wire wound tightly."
"And here. A magnet."
"Why is a magnet present?"
A sudden pause.
One student slapped his forehead. "This was in Middle School Physics."
Another gasped. "The motor chapter."
Faces lit up.
They had studied electric motors before. They had memorized formulas and diagrams. At the time, it had seemed abstract, distant, almost mystical.
Now the physical reality lay before them.
Memory and understanding fused together.
"A current carrying conductor experiences force within a magnetic field."
"The direction of the force depends on the direction of the magnetic field."
Voices overlapped in excitement.
"I understand now."
"These copper coils are the conductors."
"The magnet generates the magnetic field."
"When current flows through the coils, the magnetic interaction produces force."
"And that force causes rotation."
One student could barely contain himself. "So long as electricity continues to flow, the rotation continues. Continuous rotation. Continuous motion."
Song Yingxing looked at the disassembled motor, then at his students.
In that moment, something shifted.
They were no longer merely recording existing knowledge.
They were beginning to command it.