Although Wei Ming always has his own yardstick in his heart about who to trust and who to guard against......

But since Qinghong was already so straightforward, Wei Ming naturally couldn't have any indication at all.

Completely indicating, it is equivalent to pushing the person who wants to get close away from the side......

This kind of result is dangerous for people who simply cannot be separated for the foreseeable time.

Therefore, it is the right way to express goodwill and control the tightness of the rope in your own hands.

It is also for this reason that when Huang Maoshan was taught to purify salt, Wei Ming did not hide it anymore, but allowed Qinghong and Yueru to observe from the sidelines.

Salt, the process of going from the salt mine to the table, has been a choice for a long time, and the process of filtration, the process of purification, has been involved in it for a very, very short time.

The same is true of today's salt, of course.

For this reason, although there are a large number of salt resources in both the sea and salt lakes, the salt that can be collected and eaten by simple filtration is very, very small, and it is generally produced in salt wells such as Shudi.

Nowadays, these official salts in Chang'an City, which exude strange smells and bitterness, are already the best salt that can be sent to the table to eat and replenish the body, but will not be eaten into poisoning and other major problems.

The raw materials used by Wei Ming are these official salts, which are supplemented by the purification process that was not integrated into the previous collection.

All salt mines, whether salt lakes or sea salt, contain nothing more than that; Magnesium chloride, calcium chloride, potassium chloride and other ......

Among them, magnesium chloride is highly toxic.

The reason why well salt can be eaten after simple filtration is that it contains less toxic magnesium chloride.

But less does not mean nothing.

Therefore, the first step of purification is to add lime milk made of lime with water and stir it with official salt, so that the calcium carbonate in lime milk reacts with magnesium chloride to form solid magnesium carbonate......

By standing still, the removal of magnesium chloride can be completed.

Although calcium chloride is non-toxic, the strange smell in salt is brought by it and must be removed.

In the laboratory, calcium chloride is generally removed with soda ash.

It's a pity that at the moment, soda ash is obviously a luxury, and caustic soda and the like are available everywhere, and they are barely available......

However, Wei Ming did not do this, he took a relatively troublesome method - adding a large amount of plant ash to the brine with magnesium chloride removed, using the potassium carbonate and calcium chloride in the plant ash to react, so that calcium chloride can be decomposed into calcium carbonate and potassium chloride, and then using the difference in precipitation temperature to decompose calcium carbonate and potassium chloride......

After evaporation, you can get sodium chloride, which is the purest salt.

This series of operations, even the big tiger who has done it himself a few times still feels magical, not to mention Qinghong Yueru and Wang Maoshan!

They couldn't have imagined that there was no difference in salt, and that so many things that seemed to be similar, but tasted completely different, could be decomposed from it!

"Since this is the only salt ...... of all these salts"

Qinghong frowned and asked, "What are the remaining things—are the remaining things of any other use?" ”

Wei Ming glanced at Qinghong appreciatively, and at the same time couldn't help but glance at Dahu.

After all, it's been so many days, but Dahu has never asked him this question.

Various compounds, of course, have their own uses, compared to the magnesium and calcium carbonate obtained by purification today......

Of course, the most useful at the moment is undoubtedly potassium chloride.

Potassium is produced naturally in small quantities, but it is an indispensable element for its growth.

After a simple ratio of potassium chloride, it can be made into potassium fertilizer......

In this year when agricultural production is only farmyard fertilizer, potash fertilizer is undoubtedly a nuclear weapon.

Even in the absence of any high-yielding varieties such as hybridization, doubling the yield per mu with potash fertilizer is definitely a breeze!

"Doubling the yield per mu?"

Hearing this, not to mention Dahu and Huang Maoshan, the second daughter of Qinghongyueru, who had never been in contact with farming, were all stunned and widened.

Obviously, even they know very well that if potash fertilizer is used in large quantities, it will have a earth-shaking impact on Datang!

"It's top secret, and I don't want anyone but the four of us to know about it, understand?"

After saying this, Wei Ming went back to the room directly, and just glanced at the two of them with deep meaning from the corner of his eye......

Obviously, at this moment, the right to become a family member or an outsider has been handed over to the second daughter herself.

In the afternoon, several people were enthusiastically repeating the entire purification process.

Even though it was repeated many times, every time I saw potassium chloride and other elements precipitated in the saturated solution, I still couldn't help but cheer, and I looked like a child getting his first toy.

For this simplest chemical reaction, Wei Ming naturally didn't have any interest, but just went out to a fireworks shop when it was close to dark.

"I wonder what Xiaolang needs?" The shopkeeper asked with a smile on his face.

"Two hundred catties of black powder, ten catties of saltpeter and sulfur, and some fire twists!"

While Wei Ming said, he didn't forget to take out the paper and demonstrate: "The fire twist should be made longer and thicker!" ”

"The shop only sells fireworks, as for other ......"

The shopkeeper was about to refuse, but he saw the official talisman that Wei Ming put on the counter, and hurriedly changed his words: "I don't know when Shangguan needs it?" ”

"I'll pick it up the morning after tomorrow, and I'll give it as soon as I need it!"

After explaining, Wei Ming did not go home directly, but walked around.

It has been a long time since I traveled back to this era, and there have been some times when I have stayed in Chang'an, but it is the first time to enjoy the scenery of the Tang Dynasty alone like now.

Before you know it, it's dusk.

Just when he saw that it was getting late and Wei Ming was about to go home, he heard a rapid whistling sound!

Several strong men roared in front of them, holding short blades and slaughtering, and the speed was very fast.

The man who ran ahead was obviously wounded, but he was still fierce, and walked and walked, ignoring the blood on the ground......

Wei Ming naturally didn't care about this kind of thing, and after avoiding it far away, he had to take a shortcut back to Changshoufang.

It's just a coincidence that just as he passed through a few narrow alleys and saw that the house was not far away, the shouts sounded from all around!

"I'll go, won't I be so unlucky?"

Just when Wei Ming was secretly depressed and wanted to run a few steps to leave, there was a pop in front of him, but he saw a figure covered in blood, rolling down from above-not the fierce man before, who else could it be?

As soon as he landed, the fierce man turned over and rose again, rushing forward with his blade!

But obviously, it's too late!

In the alleys before and after, there were already blade-wielding men, approaching like tigers and wolves, their eyes staring at the fierce man at the same time, they were also paying attention to Wei Ming.