Huang Shu drilled out naked from the tunnel and returned to that prison cell. With his loincloth wrapped around his head, only exposing a pair of eyes, he first stood on the ground with ears pricked up, listening for a moment. Hearing no other sounds, he untied the covering cloth from his head and let out a long breath. Unable to rest even for a moment, he scooped up handfuls of earth dug from the corner wall and carefully sprinkled it on the earthen prison floor, then used his feet to tamp the ground flat. He lay prone on the ground again, using his eyes to gauge the ground’s levelness. After making slight adjustments, he was finally satisfied and grabbed the water jug on the table, gulping greedily.

He was still very thirsty but didn’t drink more water. He held a mouthful of water and sprayed it onto a cloth, using it to wipe his body until not a speck of soil could be seen on his body, then finally stopped. He put on his clothes, lay on the bed, and closed his eyes to rest.

For a whole month, every night he had dug ceaselessly without sleep or rest. To avoid arousing suspicion, he spread the earth evenly on the ground, gradually raising the floor level. Unless one was extremely perceptive, one wouldn’t notice the floor rising every day. That little spoon had completed its final mission. Although it had been ground exceptionally sharp by the yellow earth, it couldn’t withstand continuous digging for an entire month. Just tonight, it had finally broken into two pieces.

Huang Shu was somewhat sentimental. He planned to have such a spoon reforged after escaping, keeping it by his side. Using it to eat or dig earth in times of crisis would both be good choices. He even wanted to introduce this convenient tool to the woman who sold fermented rice wine. One’s own stall needed some special features, right?

Drinking fermented rice wine in big gulps from the mouth was truly undignified, completely lacking the elegance of scooping it spoonful by spoonful. The habits of wealthy families—surely one must learn a trick or two, right? In the future, when his own children grew up, if they held bowls and poured fermented rice wine into their mouths, he’d beat them hard. He wouldn’t dare hit their faces—the children were still young—but their bottoms would be no problem.

Having three children would be good. That woman had wide hips—clearly good for childbearing. Two boys and one girl would be fine. If the boys looked like him, it didn’t matter. They’d follow the trade of tomb raiding captains anyway. Dead people don’t care what you look like.

But the girl couldn’t—she had to take after her mother. If she turned out looking like him, who would marry her? But no matter. He still had three hundred strings of cash hidden under the ghost willow. When the time came, with a generous dowry, finding a good young man wouldn’t be difficult.

In drowsy sleepiness, he seemed to see the woman who sold fermented rice wine leading three plump children toward him, smiling sweetly, calling “husband” while the children called “father” and rushed toward him.

“Tomorrow night, I’ll escape and never come to this cursed place again.” Huang Shu muttered, turned over, and fell into deep sleep.

At dawn, Li Tai carried a small iron bucket and filled it full of hot water, returning to his dormitory. As a prince, the only privilege he could enjoy at the academy was having his own room. The room wasn’t large—not even as good as the imperial palace’s woodshed. Yet Li Tai was very satisfied. Compared to others sharing rooms four to a space, this was far superior.

He had inadvertently visited one such room. The terrible sour stench nearly made him pass out. These bastards—after playing ball, they didn’t even wash their feet before sleeping. He didn’t know how they could eat and sleep in such a room. Li Tai thought even a pigsty would be cleaner than their room.

These past few days, Li Tai hadn’t gone to see Huang Shu. He had already grasped Huang Shu’s work progress. With the guards’ help, he added a type of medicine to Huang Shu’s food. This medicine was obtained from Sun Simiao during medical class, given only after guaranteeing no wrongdoing would be done—just a tiny bit.

But the medicine was very effective. After eating, Huang Shu slept like a dead pig. After carefully measuring the volume of earth Huang Shu had dug, Li Tai felt his arithmetic problem was nearly complete. He hadn’t measured the hole behind the bed—under known conditions, it wasn’t necessary. If Huang Shu could exceed his expectations, he wouldn’t mind pleading for Huang Shu, having the academy spare this fellow. If he didn’t exceed expectations, then Huang Shu’s life or death had nothing to do with him. He only cared whether his arithmetic problem was correct or not.

Looking back at Huang Shu’s work progress chart calculated on the wall, he took out a charcoal pencil and filled in the number “one chi” at the very top of the form.

Picking up his book—they were all new books, still emitting that strange ink smell—he liked this smell. Placing the book against his nose and taking a deep breath, he was somewhat impatient to know what the book contained.

Last time, Yun Ye said that one large and one small iron ball dropped from a height would land simultaneously.

How could there be such an absurd thing? How could a ten-jin iron ball possibly land at the same time as a one-jin iron ball? If this were so, would weight even matter?

A one-hundred-wen wager—this was proposed by that fellow Yun Ye. Li Tai wanted to raise the stakes, but Yun Ye refused, which deepened his suspicion even more.

Since they wouldn’t bet money, Li Tai proposed a physical challenge.

One hundred loads of water—carry a full hundred loads of water, not from the river in front of the academy gate, but fetching water from the waterfall at the mountain’s base and carrying it back. The round trip was a full li. He originally thought that lazy worm Yun Ye would refuse, but unexpectedly he agreed.

Li Tai chose the iron balls—one weighing one jin, one weighing five jin. Under the supervision of all the academy’s teachers and students, Liu Xian carried the iron balls on his back and climbed Eagle Beak Cliff. They stood on the grassy area below the cliff, preparing to observe what would actually happen.

Liu Xian was a true expert. Standing on Eagle Beak, a full hundred chi high, without the slightest fear, he held the two iron balls painted red steadily in his hands. Li Tai didn’t even consider the possibility that Liu Xian would cheat. He was the Li family’s most trusted servant, bar none. The reason Father Emperor dispatched him was because of his loyalty—no matter what happened, he would never betray the Li family. This was proven by history.

Liu Xian released both hands. The two iron balls simultaneously dropped from his hands.

The two iron balls hit the ground. Li Tai only heard one sound. The imagined scene of the large iron ball landing first didn’t appear—the two iron balls truly landed simultaneously. Li Tai inspected the iron balls on the ground. No mistake—one was five jin, one was one jin. The entire grounds erupted in uproar.

He looked at Yun Ye in bewilderment. This overturned his common sense about life. He needed Yun Ye to explain it to him.

Yun Ye, with a cucumber in his mouth, pulled Li Tai over from below the cliff and waved the cucumber in his hand toward the mountain. They saw Liu Xian on the mountaintop throw down two more iron balls. One instantly smashed into the ground. The other iron ball, carrying an umbrella behind it, slowly drifted down from the mountaintop, blown by wind to a distant place.

Li Tai widened his eyes, wanting to understand why such an incredible thing would happen. Even the academy’s several teachers didn’t understand the principle.

“The iron balls’ falling speed is related to air resistance, not to the iron balls’ weight.”

“What is air resistance? Why can’t I see it?”

“You saw it. Wasn’t that iron ball carried away by air resistance?”

“Does this mean that as long as the umbrella is large enough and sturdy enough, even if I carried it and jumped down from the mountain, I wouldn’t be killed?” Li Tai was somewhat fervent.

“That’s the principle. You won’t actually test it, will you? Never do such a thing, or your father will throw me down the mountain like an iron ball.”

Yun Ye had said that once one comprehended physics, one would enter a realm—a realm of the gods—where one could fly, dive into the sea, and destroy this world with a turn of the hand.

There was no mistake. This was the power of gods. I must grasp this power. I must master this power.

Thinking of this, Li Tai’s body involuntarily began to tremble…