Sky Curtain: My Great Qin must have an aircraft carrier!

After studying his major courses for three days straight, Lu Li felt completely out of control.

He flopped onto his dorm bed, pulled out his phone, and started watching short videos.

As soon as I clicked in, a shiny bald head was thrust right in front of the camera.

Lu Li chuckled. "Principal, it's you again?"

[Essential skills for time travel: The principal teaches you how to handle glass by hand—your advantage is in my hands!]

As the title popped up, the principal's iconic bald head appeared in the center of the screen, with two laser beams shooting from his eyes.

A student asked me, "The last time I taught you how to rub fine salt by hand, it was too dangerous. It got killed as soon as it was made. Is there a safer way?"

I don't understand. Can't you hand-roll tons of glass? If you can't even do something this simple, what kind of time travel are you talking about!

The Huangpu Grand Classroom is now in session!

Under the sky, countless people erupted in cheers when they saw that bald head.

"The principal is the one who taught us salt making!"

"Quick, quick, get the pens and ink from home! The principal is going to teach us how to make money again!"

"Glass? What's glass?"

"Whatever it is, what the principal teaches must be good stuff, everyone quickly write it down!"

Since the last time the salt was fine, the principal's bald head has become a golden brand.

Wealthy families across the country have made a fortune by refining fine salt using the methods of the Sky Curtain Sect.

The people in those remote towns and villages realized the mistake too late and are now regretting it so much that they are beating their chests and stamping their feet, afraid of missing the next opportunity.

Now that the principal has reappeared, we can't afford to be any slower.

At the same time, all the emperors summoned painters to come to the palace to observe the celestial canopy.

Jiang Guangtou stood with his hands behind his back, his tone exuding confidence.

As many time travelers know, glass was a treasure in ancient times that was worth as much as gold.

You can easily make a fortune by simply rolling a few tons of dough, marry a beautiful and wealthy woman, and reach the pinnacle of life!

If you're bold enough, you could make it into a telescope and present it to the emperor, easily earning a noble title in return.

telescope?

What is this?

Just as everyone was wondering, Jiang Guangtou took out two round pieces of glass from his bag.

"The principle behind the telescope is very simple, but it wasn't discovered until the early 17th century. Watch closely!"

Jiang Guangtou raised the two pieces of glass and aimed them at the distance.

Through those two small lenses, the originally blurry distant view became crystal clear.

All the ancients held their breath.

What kind of sorcery is this? Is it some kind of clairvoyance?!

After a brief period of deathly silence, the courts of all timelines were shaken.

"This is a divine artifact!"

Li Shimin rested his hands on the dragon-shaped table, recalling the hardships of his campaign against Tuyuhun.

Relying on their familiarity with the terrain, the Tuyuhun would flee when they couldn't win and hide in the continuous mountain ranges.

Duan Zhixuan ran himself ragged, spending a whole month in Qinghai, but didn't even catch a glimpse of the enemy.

As a result, less than two days after returning to the capital, news of the Tuyuhun attack on Wuwei was sent to Chang'an.

Li Shimin had no choice but to swallow his pride and ask Li Jing to come out of seclusion, which finally allowed him to pacify Tuyuhun.

If the military were equipped with these binoculars...

The iron cavalry will just crush them; there's no need to suffer such humiliation!

Not only Li Shimin, but also Fang Xuanling and Changsun Wuji, among others, thought of the use of telescopes.

In truth, the content is worthless, but no one thought of it for over a thousand years.

If operated properly, Datang can maintain its technological lead over the surrounding areas for at least several decades.

"Auxiliary equipment, summon craftsmen immediately."

Li Shimin solemnly instructed: "This item must be kept strictly confidential and must not be leaked."

Changsun Wuji naturally understood and immediately pledged his life as collateral.

-

Jiang Guangtou, still exuding a mysterious confidence, began his explanation at a leisurely pace.

Transparent glass also existed in ancient times, but it was extremely rare. If you could make transparent glass by rubbing it, no one could crack the secret formula.

So here's the question: everyone knows that glass is made by burning sand.

But reality is not so simple. Sand has a melting point of over 1700 degrees Celsius, which was almost impossible to achieve in ancient times.

But how did the principal manage to make it? Because I found the secret weapon—fluxing agent!

The principal reached under the table and took out three discs containing powders of different colors.

He picked up one of the plates of white powder.

[The simplest method is wood ash, but not just any grass will do; we need to find halophytes near saline-alkali lands.]

A salt flat appeared in the sky.

On the grayish-white ground, clumps of low-lying plants grow crookedly close to the ground.

The principal casually pulled one out and shook off the alkaline soil from its roots.

The method of identification is very simple: if it tastes salty, then it's right. You can look for it while you eat it.

If you see any small red berries, you can try them; they taste quite good.

As the camera zooms in, a few bright red berries are seen among the branches of the saltwort.

Is this even edible?

"That's great! If there's a famine in the future, won't we have another way to survive?"

"Quickly write this down: it's salty, and the fruit is red!"

Several daring young men couldn't contain themselves any longer and were preparing to leave the village to try their luck.

Just then, the principal shrugged.

However, eating it usually leads to death, because it tastes so good.

It's okay if you eat it, since I'm not the one who'll die.

"You bald monk, you think you can make a fool of us!"

"Why didn't you say it was poisonous earlier? You had to insist it tasted good! That's just unethical!"

"I almost went and tried it, that bald guy is so mean!"

The people who were just about to go out reluctantly pulled their feet back and cursed at the sky.

The principal straightened his posture in front of the camera and began to speak seriously.

Okay, enough joking. Dry the collected saltwort in the sun for a few days, then put it in a stove and burn it into powder.

After burning, you will get a pile of white powder, which is salt grass ash.

Put the ash into water, filter it through Widow Wang's clothes, and after burning it dry, you'll get a bowl of sodium carbonate.

"Why does it have to be Widow Wang's clothes? Can't Widow Li's be used?"

Someone in the crowd muttered something, and several men around him immediately echoed it.

"That's right, the clothes of Widow Zhao from the next village are much finer than those of Widow Wang."

"Stop talking nonsense. Did you borrow any salt last time you were making it?"

"I lent it to her, and Widow Zhao almost hit me out the door with a rolling pin."

"Then that settles it, right? Widow Wang is so generous, whose money do you need?"

"That's true."

After much discussion, everyone reached a consensus—

Anyway, it's not my own clothes, as long as it's a widow's, don't worry about the details.

In the sky, the principal took out another white crystal.

The object was translucent with sharp edges, and it refracted a faint light under the sun.

The principal held the crystal up to the camera lens and spun it around twice.

Considering the conditions in ancient times, sodium carbonate alone was not enough; we also needed a second fluxing agent—borax.

Borax is everywhere along the salt lake. If all else fails, you can even steal some from a Taoist priest who practices alchemy.

Taoist priests often use borax in alchemy. If you befriend them, the deal will be done.

As for sand, there's no need to explain, you can dig it up anywhere, whether it's a beach or a desert.

However, there is one thing to note – the sand must be thoroughly washed!

Use Widow Wang's sieve and the water-whisking method to wash it thoroughly; don't be lazy!

"Is it Widow Wang again?"

"What exactly is the relationship between the principal and Widow Wang? With all this talk about clothes and sieves, could they be...?"

A group of people looked at each other and whispered among themselves.

The old man selling pancakes nearby didn't care: "Why bother with so much? Instead of gossiping, you should write down the recipe."

That makes sense.

Everyone agreed and stopped dwelling on the issue.

The principal poured all the materials into a large bucket and stirred them vigorously.

Mix sand, sodium carbonate, lime, and borax in a ratio of 6:2:2:1 until homogeneous.

Then, while Old Wang next door wasn't home, he put the crucible into his porcelain kiln.

The principal lowered his voice and winked at the camera as he spoke.

[Remember, it's about putting it in, not secretly putting it in. Can you call something a scholar does stealing? That's called resource sharing!]

"Ha ha ha ha!"

Countless people laughed so hard they almost cried.

That principal is so mean!

Using Widow Wang's clothes and sieve, and still trying to steal from Old Wang's kiln, Old Wang must be having a cuckold's horns on his head.