On the 10th day of December, after Li Yuan and his entourage successfully returned to Lizhou City, they immediately issued an order to supervise the capital, and Lin Sichang, the former commander of the army, was transferred to the post of Lizhou Assassin to control the military of Lizhou.

It is worth mentioning that after Li Yuan led the guards to return to the south, the new assassin Lin Sichang immediately convened the civil and military forces of Lizhou in the Assassin Mansion, and the people naturally did not know what these officials and masters discussed, but only knew that in the whole month after that, the city made great moves, first the Assassin Mansion issued a notice to recruit 5,000 people, and then there were often a large number of soldiers and horses galloping back and forth on the street, and the money and grain in the treasury also kept being transported outside the north gate......

On the way back to Langzhou, Li Yuan specially instructed his guards to feed the yellow horse a lot of boiled and purified salt water without interruption, the purpose of which was naturally to be more sure whether this salt was really safe. It's just that Li Yuan is worried that a small amount of intake may not be unusual, and this yellow horse is indeed alive and kicking at the moment, but if it is eaten for a long time, it may bring serious consequences.

However, this yellow horse was very angry, full of energy along the way, and he couldn't see the slightest abnormality, and Li Yuan finally put his mind at ease.

After returning to Langzhou, the first thing Li Yuan did was to send several unknown things obtained from Yanjing to Taoist priests such as Liu Haichan and Du Yulin for identification, and this kind of thing could only be consulted by professionals like them.

Soon, on the afternoon of December 15, Liu Du and the two real people came to the Dadu Governor's Mansion under the leadership of Hu Gui to ask for a meeting, and Li Yuan immediately placed tea and tea in the shade of the atrium.

"Two real people, is there any good news? Could it be that the fire of the Pontus Governor has been refined?" Li Yuan leisurely drank tea and sat on the chair, looking at the two warlocks in front of him with excited faces.

Liu Haichan and Du Yulin's faces were suddenly full of shame, and it was hard to speak, Li Yuan saw a little strange appearance from them, waved his hand and smiled, "Just kidding, I know that you are still working hard. Pontus wondered if he had identified what I had given you."

Liu Haichan hurriedly arched his hand and said, "Yes, Dadu Governor, fortunately, I am not dishonored! Lao Yu and Du Zhenren have not slept for a few nights, but they can be regarded as figuring out what the Metropolitan Governor has given us. You see, it's the yellow grains of salt in this bag, which are a mixture of coarse salt and a lot of strange impurities.

The decay was separated by washing it with water, and finally the salt and miscanthus and other unidentified debris were obtained, and the amount of miscanthus accounted for the vast majority."

Li Yuan was surprised: "Manganese? It turned out that it was mixed with miscanthus salt, but I didn't expect that there was miscanthus in the salt well."

Du Yulin was clever, swallowed his saliva and said, "It turns out that the Metropolitan Governor obtained this kind of thing from the salt well, so it is not surprising."

Li Yuan consciously lost his words and revealed the truth, and he originally planned not to mention this matter for the time being, so as not to cause trouble. After coming back, he and Zou Ping's relatives and guards told him not to mention the matter, but he didn't expect that he had leaked his mouth. But it doesn't matter, for these alchemists in front of them, the only thing they pursue is immortality.

"Well, it's true that it was obtained from a salt well, but I didn't know that the salt well actually produced mango salt, and the governor of Pontus thought it was all salt." Li Yuan smiled.

Liu Haichan arched his hand and said, "Most of the governors don't know that salt and nitrate are one thing, and where there is salt, there must be miscanthus salt. In the past, I heard my brother say that there was a salt lake in the old Uighur land in the north, and the local people fished for salt in the summer and nitrate in the winter, and the salt and nitrate were dissolved in the lake water at the same time, which can be seen."

"I see." Li Yuan nodded, puzzled, "But I don't know why it's salt fishing in summer and nitrate fishing in winter. What's the point in that?"

Liu Haichan frowned and thought for a while, then responded, "This...... Lao Yu has done this investigation, and specially verified it with salt and nitrate mixture. The so-called summer is nothing more than the high temperature, the water temperature is also high, and the water vapor is transpiration, which will make the dissolved salt in the water analyzed, similar to the method of drying salt or boiling salt. But this miscanthus is different from salt, a bucket of water or dissolved salt is one liter, but this miscanthus nitrate can be dissolved as much as two liters.

Even if the salt is completely precipitated, this miscanthus is still in the water and does not precipitate. But how much this miscanthus dissolves in water depends on the temperature of the water. When the water temperature is so low that it is cold, it is difficult for a bucket of water to dissolve even half a liter of miscanthus salt, but salt does not have this property. All things that cover the heavens and the earth have their own characteristics,

That's the strange difference in its characteristics, it's amazing."

Li Yuan reacted immediately, to put it bluntly, it was a matter of solubility. The solubility of miscanthus fluctuates greatly with the change of water temperature, while the salt remains basically unchanged. In summer, the salt crystallizes when the water evaporates, and in the winter, when the temperature drops, the salts in the water crystallize.

Although it is a simple knowledge of junior high school chemistry in later generations, it is not easy to figure it out in this year. Liu Zhenren is also a qualified alchemist, and if he can deliberately go to an experiment to test it, he can be regarded as an ancient person with strong curiosity.

Du Yulin also smiled and said, "As Liu Zhenren said, we use the method of steaming, we dissolve all the poisonous salt brought by the Metropolitan Governor in clean water, boil it in a kettle, and pour boiling water when the water is halfway dry. What is precipitated under the copper kettle is table salt.

Take out the salt, continue to boil the soup, and when the soup is almost dry, pour out the wastewater, and what is precipitated in the kettle is miscanthus salt. Sixty percent of the pound of poisonous salt is salt, thirty percent is salt, and the rest is not known to us, so we can only dump it with the wastewater."

Li Yuan smiled secretly in his heart, isn't this the method he used? But he still pretended to be dazed and nodded.

The words of the two real people are also very crucial, since it has been identified that the poisonous salt contains miscanthus salt, it is a good explanation of the cause of death of those Chu soldiers back then, because the miscanthus is toxic, not to mention that it is mixed with other things, there is no need for many highly toxic things, and some only need a little to kill people, but it is all in the past, and there is no need to dwell on it.

"The two real people really have a good method, they actually have this method to separate the salt from the miscanthus salt, and they don't have to wait for the winter and summer seasons to change when they use the boiling method. Ay...... It's a pity that these cancanthus salts, except for your alchemy and medicinal uses, are not what Pontus wants. It's a shame that it can't be used in the fire." Li Yuan said with deep regret.

Liu Haichan sighed lightly: "Yes, it's a pity, the miscanthus is not used for ambushing fires, which is indeed a pity. However, miscanthus can be used for medicinal purposes, and it can be used for our alchemy, and it is also very useful."

Li Yuan waved his hand and said with a smile: "Come on, the Governor of Pondu is not interested in alchemy, this thing is worthless in my opinion, if it is fire, it would be great, and the Governor of Pondu will not let Mr. Xu and Hu Gui mobilize the people in the whole territory of Wuping to clean the frost of the pig house, sheep pen, and livestock shed."

Liu Haichan suddenly smiled and said, "Don't worry, the Metropolitan Governor has good news to tell you."

Li Yuan was stunned and said, "What?"

I saw Liu Haichan smiling and taking out a cloth bag and spreading it out, which was a large piece of colorful crystalline things that Li Yuan had collected.

"Governor, we recognize this thing you brought. This kind of thing must have been obtained by the Metropolitan Governor in the salt well."

"yes, what is this?" Li Yuan asked hurriedly.

"Congratulations to the Duke, congratulations to the Duke. This thing is called treasure saltpeter in our mouths, not only because of its colorful shape like a gemstone, but also because this saltpeter is very rare. The old decay has been refining medicine for decades, and the obtained thing is only a few jars. That's a good thing." Liu Haichan smiled.

Li Yuan said, "Treasure saltpeter? Can it be used as a fire-ambushing party?"

Du Yulin on the side rolled his eyes, the only thing that the Metropolitan Governor cared about was whether it could be used as a fire ambush, but he didn't ask what the value of this thing was.

"Saltpeter is not to be used for fire." Liu Haichan said honestly.

Li Yuan was greatly disappointed and sighed, "What kind of good news is that? It's not a gemstone, and it can only be alchemy, what's the use?"

Liu Haichan smiled, "Don't worry. From the point of view of the old man, the saltpeter is quite valuable, but what the old man said is that although it cannot be directly used as an ingredient for the fire party, it only needs to be converted slightly to obtain the fire nitrate."

Li Yuan exclaimed, "Can this thing be transformed into fire nitrate? That's great."

Liu Haichan said: "Of course, if you use treasure saltpeter and plant ash to blend with water and boil at high temperature, the thing obtained after the water is dried will be fire nitrate. It's just that...... It's just that it's tyrannical.

According to the ancient scriptures, alchemy with treasure saltpeter, there is a chance to get the elixir, and the body of the suit is as light as a swallow and floats like a fairy, which is the best raw material for the elixir refining. Doesn't the Metropolitan Governor consider taking the test?

Are you thinking of using these precious saltpeters to refine the elixir?"

Li Yuan smiled awkwardly and said, "What kind of elixir to refine? The governor of Pontus is nostalgic for the world, but he doesn't want to become an immortal, he just needs to become a fire and practice a fire. Now it's okay, the success of the fire side is expected, you have to work harder, there is no progress day after day, and the governor of Pontus is very anxious."

Liu Haichan and Du Yulin glanced at each other, and they were secretly deflated in their hearts, they came to see Li Yuan today, originally to persuade Li Yuan to use these treasure saltpeters to refine the elixir, but obviously Li Dadu Governor had no interest and wasted these precious raw materials in vain.

Li Yuan seemed to see through the thoughts of the two real people, and laughed lightly: "However, the governor of Pontus can promise you that as long as you complete the refining of the Fuhuo Fang for me, I can give you some precious saltpeter for you to refine the elixir. But if you refine it, you will become immortals one day, but don't forget to continue to help Pontus, hahaha......

Liu Haichan and Du Yulin were overjoyed, and finally had some hope, but they still asked uneasily, "Dadudu, do you have a lot of saltpeter in your hands?" It's not easy to see."

Li Yuan smiled and said, "There is everything, there is a lot, you put your heart in your stomach, it is enough for you to refine the elixir."

What Li Yuan said was indeed not a big deal, in that salt well, there were a lot of colorful so-called treasure saltpeter, and the clusters looked like flowers growing on top of the poisonous salt. The pieces are convex like cones, and the daylight is shining, and you can see the full of brilliance when you look down along the stone wall of the wellhead. This is only the dozen or so large salt wells that have been excavated, and if dozens more are opened up in the future, the output can be described as amazing.

It's everything, and it's not bragging.

After sending off the two real people, Li Yuan was in a very happy mood. The harvest of this trip to Lizhou summed up, Li Yuan never thought of it, the so-called grass and rabbits by the way, not only salt, but also the raw materials of fire and nitrate, it is really an unexpected joy, it can really be described as the favor of God.

Now there are only two things left, and therefore Li Yuan also decided to return to the capital Jinling to visit, one is to discuss the cooperation with Zhou Zong on private salt, how important this matter is, it is not clear through remote letters, and the other is closely related to the previous precautions.

It's December, and it's time for the Southern Tang Dynasty to stop paying tribute.