Transmigrated into a female county magistrate during a famine, leading her country to prosperity

The clarity of a mirror depends on the quality of the coating material.

Shen Zheng had been thinking about what kind of coating material to use.

In her memory, mercury and silver were often used for coating in ancient times.

Mercury is definitely not an option, as it is harmful to the human body, especially to the workers who make the coating. Long-term exposure will cause irreversible damage to their respiratory tract and internal organs. Shen Zheng would never do such a thing.

And silver... is even more impossible.

Silver is a real currency. If it is used to coat a mirror, the cost of the mirror will increase. How many people can afford it?

After thinking about it for several days, Shen Zheng finally remembered a kind of metal, a metal that has been underestimated by people since ancient times.

——Metallic tin.

Metallic tin is extremely ductile, and a small lump can be rolled into a large piece of tin foil. The chemical substances of metallic tin are relatively stable, and it is difficult for it to precipitate toxic substances during daily use, and it is also difficult to cause harm to the human body.

But in today's Zhou Dynasty, metallic tin is rarely used.

Either tin is used to make bronze objects, or metallic tin is used as a welding material to improve the stability of the casting process.

In Shen Zheng's words, metal tin is just a supporting role.

It's better to have it, but it's also a kind of auxiliary without it. It's a bit sad to think about it.

Because metallic tin is in such a mediocre position, there are fewer merchants mining tin, and the technology for refining metallic tin is also poor.

But this is actually a good thing for Shen Zheng.

No one cares, no one develops the value of tin, which means...

Tin ore is not expensive.

Not to mention comparing it with silver, it is not even more expensive than copper.

So Shen Zheng locked onto the tin mine and asked Diwu Tanwei to help get some ore. She had plenty of ways to purify it.

......

After dinner that day, Shen Zheng and Diwu Tanwei returned to the courtyard. Yu Nanshu was not taking part in the provincial examination, so she had extra time. She followed them back to the courtyard, hoping to hear something "new".

It was still a little chilly in the March night, with a slight chill coming with the wind. The three of them, each wrapped in a thin cotton coat, sat around the stove.

Tea was heating on the small stove, and two glass oil lamps were hanging on the lamppost, casting a warm yellow light on this small world.

The fifth tank first took out the plaster paper.

Shen Zheng and Yu Nanshu can both be called "big paper users". They have used at least eight hundred pieces of paper this year, if not one thousand. So they could tell at a glance that the paper in front of them was unusual.

Compared with ordinary straw paper, these papers have a finer texture, a more even distribution of pulp, and are not of varying thickness like ordinary straw paper.

Yu Nanshu became interested as soon as she saw it, and she ran back to her room to get some writing brush and ink, and asked Diwu Tanwei eagerly, "Sister Zhubu, can I try this paper?"

The fifth Tanwei's eyebrows curved slightly and nodded, "Of course."

Then, under the watchful eyes of Shen Zheng and Diwu Tanwei, Yu Nanshu quickly sketched out the outline of a garment in just half a minute.

Yu Nanshu has many pens, of different colors, thicknesses, and uses.

She would only dip a pen into ink of one color to avoid color mixing.

She was absorbed in her painting, her eyes were focused, and her mouth made some small movements. Shen Zheng and the other person were quietly serving water and drinking tea, for fear of disturbing her.

She dotted various colors onto the paper one by one, and the ink slowly spread out, gradually outlining a colorful picture of ready-made clothes with fluttering sleeves.

Finally, Yu Nanshu stopped writing, picked up the paper with satisfaction, and blew on it several times.

"This paper is really easy to use!" She handed the paper to Shen Zheng like she was offering a treasure, and said, "Look, Sister Shen, although the ink smudges, it only smudges in a small area, which just plays a rendering role. And this paper is very smooth, it won't suddenly absorb ink or run out of ink when you write or draw! And look at the back!"

Shen Zheng looked behind the drawing.

Yu Nanshu said: "If you write more lightly, you can even use it on your back! I think... compared with the best rice paper, this paper is not inferior!"

Shen Zheng and Diwu Tanwei both laughed.

For the Fifth Family and Tongan County, the advent of gypsum paper is a win-win business. And for students all over the world, it is also good news.

"How much does it cost?" Shen Zheng asked.

"It's slightly cheaper than ordinary straw paper." The Fifth Tanwei took out a cost booklet and introduced: "After adding gypsum, the pulp settles faster during papermaking, which greatly saves manpower and papermaking tools. In fact, these two are the biggest costs..."

As she spoke in detail, Shen Zheng and Yu Nanshu sat in the same position, one hand on the table and the other on their chins, both listening very attentively.

The night wind blew, making the shadows of the three people crooked, sometimes tangled together, sometimes turning around and separating.

As the night grew darker, Diwu Tanwei took out the site selection atlas.

"Sir, would you like to take another look at these shops?"

Shen Zheng had taken a rough look at the shops in the album before. Most of them were close to the Fifth Chamber of Commerce, and they were also protected by the Fifth Chamber of Commerce to prevent some local bullies from harassing them.

These shops are centered in Tongan County and extend in all directions from the inland waterways. They cannot be called comprehensive for now. After all, the Great Zhou is vast and it is difficult to cover them completely in a short period of time.

And these are just the first batch of locations for shops in Tongan.

Shen Zheng took a closer look at the Shangjing shop.

Shangjing is the capital of the Great Zhou Dynasty and a place where talented people gather, so one of the first batch of shops must be in Shangjing.

"There's no rush for these two shops in Shangjing." Shen Zheng pointed at the atlas and said thoughtfully, "I will leave for Shangjing next month, and I will personally inspect them then. As for the other shops... leave this atlas with me for now, and I will discuss it with everyone later."

The fifth Tanwei nodded in agreement.

......

The next morning.

After breakfast, Diwu Tanwei was reluctant to leave, and Shen Zheng took the plaster paper and tin ore to the printing house.

Today is a day off and all the students are in the workshop. When Li Hongmao saw the plaster paper, he was like a hungry cat seeing a mouse. Without saying a word, he hurriedly took the paper into the workshop.

The next moment, exclamations from the students were heard.

"The master has created a new treasure!"

"Is this the paper we'll use to print books from now on?"

"Can we write on this paper?"

"This paper looks so fine and smooth, it must be expensive... Will our printing house make even less money?"

"But we adults never thought about making money at the beginning..."

"The adults don't want to make money, but don't you want the adults to make money?"

Outside, Shen Zheng smiled and shook her head after hearing this, then pulled the small cart and went to the blast furnace room with a "clatter, clatter" sound.

In the blast furnace room, Liang Fu was lighting the furnace. He looked up at the small cart in Shen Zheng's hand after hearing the noise. "Is this the treasure you mentioned... that can be used as a mirror?"