Under the dim oil lamp, there was a faint smell in the room.

The station is not as good as at home. The lamp oil at home is made of pulverized oil and spices. It is resistant to burning and has a faint fragrance. It is very useful, but the price is a little more expensive.

Most people use rapeseed oil, while those who don’t have money use flax oil, sesame oil, and even tung oil, but the taste is extremely bad.

As for candles, they are made of ginger oil and ginseng and other oils. Most of the north use them as tallow, which is relatively expensive, so most people do not have these things at home.

Thinking of this, Zhang Mu suddenly thought of a way to make money. Although there were many disadvantages in ancient times, anything he made was a good way to make money, and he felt a little balanced.

When making soap, the oil is saponified, but the scraps cannot be used as candles because there is glycerin inside and it has a strong smell of burning. However, you can use hydrochloric acid to extract stearic acid from the soap. Although it is not as economical as paraffin candles, it is much cheaper than the candles sold now.

After all, paraffin must be extracted from petroleum. Now there is no process or ability. However, these stearic acid candles can still sell well. In this way, it not only solves the problem of making soap scraps, but also further develops oil profits and reduces production costs.

Thinking of this, Zhang Mu was a little proud, but the problem of hydrochloric acid is a bit troublesome at the moment, but hydrochloric acid can be made of salt and sulfuric acid. Thinking of this, Zhang Mu smiled bitterly again: "It seems that we have to start with sulfuric acid first."

After thinking for a long time, Zhang Mu found that the most reliable method was to use blue alum to make sulfuric acid. Blue alum can be bought from traditional Chinese medicine stores, and it is not a scarce thing.

When blue alum is 160 degrees, it can lose water and turn into anhydrous copper sulfate, but when it is 700 degrees, it can decompose into your copper monoxide and sulfur trioxide.

The temperature of porcelain and lime can be fired in charcoal kilns to reach more than 1,000 degrees, so the temperature is not a problem, but sulfur trioxide is difficult to collect.

Zhang Mu thought about it for a while and felt that it was necessary to use porcelain to burn a pipe, then study a set of blower equipment, and then introduce sulfur trioxide into the water, which can be made into dilute sulfuric acid solution and then boiled into sulfuric acid.

With sulfuric acid, if anyone dislikes him in the future, he will just spit his face. It is a good thing to travel at home and kill people and rob people.

Moreover, saponification of oil and fat can extract glycerol, concentrated sulfuric acid and saltpeter can obtain nitric acid. A mixture of concentrated nitric acid and concentrated sulfuric acid, plus cotton treated with caustic soda, that is, defatted cotton, can be made into nitrogen 1 glycerol.

However, nitrogen 1 1 glycerol is not very stable, and it explodes after shaking. Zhang Mu doesn’t want to leave for the time being.

However, this method obviously worked, so Zhang Mu hurriedly picked up his pen and wrote it on the paper. When he got home, he ordered Zhang Wenguang to burn the ceramic pipes first to make a bellows.

"Speak the gong to notify me, close the doors and windows, be careful of the candles." Then there were three gongs. When Zhang Mu saw that it was already four o'clock in the morning, he hurriedly got up and headed out of the door.

Back in the dungeon, Zhang Mu saw Li Guan leaning against the wall and staring at him. Zhang Mu opened the prison door and shook Li Guan gently. Li Guan immediately opened his eyes and asked when he saw Zhang Mu, "Can you leave?"

"Come with me." Zhang Mu said in a low voice, then led Li Guan to the back corner gate and said in a low voice: "Do you know where Duan Tiande lives?"

"I know that he has an industry in Hualan Lane behind Chenghuang Temple. I have been there once." Li Guan said.

"Then you go, don't worry, I will make a complete set of plays for you here, go." After saying that, Zhang Mu opened the corner door.

Li Guan turned around and looked at Zhang Mu, hesitated and said, "You can't break your trust if you promise me!"

"Don't worry, I'll speak for nothing." Zhang Mu said.

Li Guan gritted his teeth and said, "Goodbye." After saying that, he held the wall and limped into the alley.

Zhang Mu turned around and returned to the stable. Someone had prepared hay here at this moment. Zhang Mu woke them up. The two lieutenants hurriedly squatted down and ignited the fire. In a moment, the huge backyard was shining into the sky.

"It's gone, it's gone." At that moment, there was a sound of gongs in the backyard. Then the Jinyiwei who lived here came out of the door, but they were just pretending not to put out the fire.

Anyway, the fire could not be burned. After a while, about a dozen Jinyiwei went out from the main gate and divided into two teams. He rode his horse and searched in Li, Jinhua Mansion.

Zhang Mu looked at all this coldly, and he planned it all, just to act more realistically, otherwise Li Guan would not look like it if he escaped there.

Jiang Yan, who was yawning, obviously did not sleep. When he saw Zhang Mu standing in front of the fire in a daze, he asked, "Is this person Li Guan reliable?"

"It should be no big problem. When talking about his parents, I obviously felt that he was still very concerned about it." Zhang Mu said.

Jiang Yan asked in confusion: "Where did you see this kind of person who has been in a military life?"

"When I mentioned his parents, his hands and feet were shaking slightly, his breathing rate increased, and his eyes were distracted, and he was obviously nervous about his parents. So, I was sure to convince him." Zhang Mu smiled.

Jiang Yan looked up and down at Zhang Mu and said, "Where did you learn this from you? You know these experiences that only prisoners have had in my life?"

Zhang Mu hurriedly explained: "This is all seen from an ancient book. I thought it was a joke, so I didn't care. Later, the ancient book was burned by my father and said that I was not doing my job properly."

"What a pity, what a pity. But his mother's study is really useful. Then let's wait for Li Guan to come back." Jiang Yan said with a smile.

"Sir, I didn't explain one thing clearly." Zhang Mu said in a low voice.

"Oh? Come and listen?" Jiang Yan said.

"Li Guan will most likely not come back when he goes there, because he will be killed and silenced. The Duan Tiande he mentioned is definitely a problem. If Li Guan comes back, at least it means that Duan Tiande is not a big problem. How could a person who dares not kill people assassinate His Majesty?" Zhang Mu said in a low voice.

Jiang Yan suddenly realized that Zhang Mu used Li Guan to throw a stone to ask for directions. It seemed that he had already thought about it. Jiang Yan subconsciously felt that Zhang Mu's thirteen-year-old child was more scheming than adults, and he had to be said to be talented.

Zhang Mu continued: "If Li Guan didn't come back, we would have a goal and would not worry about not being able to find anything. If Zhang Chi's party really had something to do with His Majesty's trip, then the case would probably be in trouble."

Jiang Yan nodded with a heavy face, and Zhang Mu said again: "Sir, I promise Li Guan will release his family and ask him to make the decision."

"Don't worry, I will not break my trust when I promise you something. Tomorrow I will notify the government office to let them go. It's getting late, and I will go to bed tomorrow. Jiang Yan said.

"That sir." Zhang Mu yawned, then turned around and answered in the room.

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Chapter completed!