As soon as they got home, the children shouted, "Oh no, uncle! Poison gas! "They all gathered around. Zhang Zhimu looked over and saw that the wood switch on the biogas tank was not very tight, and there was some air leakage. The methane gas produced is bubbling out, and there is a smell of rotten eggs. The children all heard Zhang Zhimu say that the biogas was not burning and poisonous, and they were too scared to approach. The adults in the family didn't know how to get it, so they let the children stay away and wait for the uncle to come back. Zhang Zhimu didn't expect the biogas in the biogas tank to come out so quickly. stepped forward, turned the switch, and the snorting of the biogas was gone. Zhang Zhimu thought that he should try to light it now, so he twisted the switch a little, heard a sound, and there was gas through, so he went to the biogas stove, lit a small handful of grass and stretched it out to the stove, twisted the small switch, and only heard a sound of gas spurting out, but only the fire was blown out, and it was not. The children around were all very disappointed. Zhang Zhimu knew that there was air in the tube, so he let the gas out for a while, turned off the small switch, clicked the handle, and put it on the stove. The children screamed and ducked out. Zhang Zhimu hurriedly turned off the switch a little smaller, and adjusted the flame to an orchid flame more than an inch long. Then ask Sister-in-law Xu to take a pot and boil water. Everyone gathered around to see this rarity. When Zhang Zhimu came over after washing his face, a pot of water was already boiling. Zhang Zhimu turned off the switch, and the fire was gone. Zhang Zhimu said: "See, this is biogas. You see there's not a bit of ash on the pot, there's no smoke. After Sister-in-law Xu, she used this to wash clothes and boil pig food. Zhang Zhimu taught everyone how to light the fire and how to turn off the fire. In order to deepen everyone's impression, Zhang Zhimu deliberately used a biogas stove to make a few dishes for everyone at noon. Zhang Zhimu didn't expect that a plate of vegetarian fried shredded potatoes made the children grab it. In fact, this vegetarian fried shredded potatoes is still a bit particular about it. First of all, the knife work should be good, but this is the credit of Huang Yukun. Then use water to remove the starch by scooping the shredded potatoes with water. When stir-frying, the green onion is fried in the pot, first put the vinegar and fry quickly, put the salt when it is almost cooked, put the minced garlic into the pot before the pot and turn it over immediately, then it tastes soft and crispy, and the garlic is full of flavor.

Since then, the kiln has been using biogas.

Zhang Zhimu thinks that Li Yunhe has a smart brain, and in addition to his own craftsmanship and kung fu, he thinks that he should focus on training. I called him over and told him about the digester. For example, the pressure reduction effect of large valves, the filtration effect of filters, the flow control effect of small valves, the protective effect of pressure relief valves, and the approximate proportion of biogas ingredients were all told to him. Li Yunhe also remembered it carefully, and asked some questions if he didn't understand.

Zhang Zhimu said: "It would be good if there were iron pipes, which is convenient and safe. ”

"With an iron-making furnace, I can make iron pipes." Li Yunhe said. In fact, Zhang Zhimu was waiting for his words, and was about to tell him about building an iron-making furnace.

"Then build an iron-making furnace as soon as possible, what is missing, think about it." Zhang Zhimu said.

"How much gold and iron do you want to refine at one time?" Li Yunhe asked.

"Let's get one to refine one or two hundred catties at a time, and then make it bigger later."

"It's not small, and it's going to be bigger?" Li Yunhe said.

"Yes, steel. Let's build an iron-making furnace first. ”

"Then make a cupola, you can't sit on the stove." Li Yunhe said, Zhang Zhimu nodded.

"I went to see that there were some ready-made bricks in the kiln, and the material from the firing cylinder could be used as refractory materials to wipe the furnace. I also needed some limestone, charcoal a little, but not enough. Iron is enough for the time being. Li Yunhe pondered.

"In the afternoon, I will go and bring back the bricks and refractory soil, and go into the city tomorrow to buy things." Zhang Zhimu said.

When Zhang Zhimu and Li Yunhe went into the city to buy things, they brought Chen Yufeng with them. One is to go to the "God Hand Zhang", and the other is to meet the old army "Old Wu Tou".

When he entered the city and met Lao Wu Tou, Lao Wu Tou was overjoyed, "You are here, old hero, are your feet well?" I've got some good stuff waiting for you! ”

"Hmph, miss my money! At noon, you take a leave of absence and wait for me at Wu Laosan's tavern. Chen Yufeng said according to Zhang Zhimu's discussion.

When they came to Chongren Hall, the two old friends naturally laughed and scolded. After looking at Chen Yufeng's feet, Zhang Bengui said: "This old thing's feet have been saved, and it will be fine in a few days." He also took Chen Yufeng some medicinal wine and asked him to wipe it every night, so that he could recover faster. Seeing that Chen Yufeng's affairs were over, Zhang Zhimu gave Chen Yufeng a look. Chen Yufeng asked Zhang Bengui, "Now, do you still go out to buy medicine?" ”

"Buy it, the pharmacy doesn't go out to buy medicine, and you can't wait for someone else to deliver it." Zhang Bengui replied.

"Can you buy some saltpeter, sulfur, and realgar?"

"How much do you need?" Zhang Bengui asked again.

"Seven or eight hundred catties of saltpeter, one or two thousand catties are fine, and sulfur or realgar can be folded in three ways." Zhang Zhimu took it and said.

"What? You're not trying to rebel, are you? Zhang Bengui said.

"How dare we want to open a mountain and blow up stones." Chen Yufeng said.

"Honestly, you old thing."

Zhang Zhimu said that he was going south to buy grain and wanted to prepare a firearm.

Zhang Bengui said: "This saltpeter and sulfur government is strictly controlled. But as long as there is, there is no goods in the world that we Shanxi people can't buy. In fact, you need a small amount of saltpeter urgently, those shops with cooked leather are in stock, and cooked leather is inseparable from this thing. Listen to my letter. ”

"If there is a stock, I am not afraid to have more." Zhang Zhimu said.

When I came out of Chongrentang, I first bought the things I needed, and then went to the blacksmith shop to order some iron-making equipment, and left some fixed money, and the blacksmith told me to take it in three days.

When I came to Wu Laosan Tavern, Old Wu Tou was waiting in front of the door. Several people entered the store together, found a secluded place and sat down. After ordering the wine and food, Chen Yufeng spoke first: "You have said several times that you have a good business, let's say, what did you get again." Old Wu Tou looked at Zhang Zhimu and Li Yunhe, but did not squeak. Chen Yufeng said: "There is no outsider here, let's say it!" ”

"Now there are a few good longbows and crossbows, as well as some spears and waist knives."

"Now, the Shenji Battalion in the Ming Army has been replaced, and it has been eliminated, right?" Zhang Zhimu knew that the Yuan and Ming dynasties were a period of rapid development of firearms due to years of war.

"No, no. How can there be so many birds? Only the Shenji Battalion has changed. Most of them still use this longbow and crossbow. ”

The food and drinks were served, and several people took a sip. Old Wu Tou began to talk a lot, "It must be explained that the army is not good at fighting, but weapons are all good things." The longbow is two stones, and the crossbow is two stones. ”

"I thought you had something good that we wouldn't need." Chen Yufeng said deliberately.

"Is there a crossbow that can throw stones?" Zhang Zhimu asked.

"Yes, this kind of hard crossbow can be loaded with a holster, and it is all up to it to throw stones when defending the city."

"How much money are you going to make?"

"The crossbow and the bow were fifty taels, five taels each, and five bundles of bows and arrows, five bundles of fifty, and a bundle of ten taels of silver. There were twenty weapons and twenty guns each. Old Wu Tou said.

"We can't get these things from you, and if we want these things, we will go to jail." After Chen Yufeng finished speaking, he stared at Lao Wu Tou and said, "I'll give you a price, if you agree, I can inquire for you, do your friends in Dao'er buy anything?" ”

"Just about the same, just fast. Old heroes. Old Wu Tou said.

"The crossbow and the bow are forty taels, and the bow and arrows are eight taels of silver. Weapons, swords, and guns are fifteen taels each. Chen Yufeng said.

"'Mountain Harrier', you're too dark." Old Wu almost jumped up.

"You taught the 'Mountain Harrier'?" Chen Yufeng's eyes widened.

"I'm damned, I'm damned. It's up to you, old hero. Old Wu Tou hurriedly made amends.

"That's pretty much it. If someone asks for it, I ask him to go to the city gate to find you, and I say that I asked him to find you, understand? ”

"Understood, understood."

Zhang Zhimu said: "Do you have any of us that we can use, like a fire gun or something?" ”

Old Wu Tou hurriedly shook his head, "No, it's too strict, no one can do it, if you catch this idea, you will be beheaded." ”

Zhang Zhimu deliberately asked Chen Yufeng, "Last time, you said that a friend asked for a hundred catties, do you want it?" Look at Lao Wu here, can you do him a favor? ”

"yes? Old Wu Tou. Black ** But someone asked me, there is something to ask. Chen Yufeng understood that Zhang Zhimu wanted to **.

"**? Supposedly you can get it, after a few people, is the price? "Old Wu Tou deliberately took a handful.

"Then forget it, Uncle Chen, don't make trouble for Lao Wu, we won't be able to get any good." Zhang Zhimuxin said that fighting with me is hundreds of years.

"Don't, fifty pounds for one box, two boxes for one hundred taels."

"What is the minimum?" Chen Yufeng asked.

"That's eighty taels."

"That's right, you give me an accurate number, and I'll tell them. **, I can decide, my friend can come back next month, as soon as he comes back, I will ask him to come to you. ”

Out of the tavern, see off the old Wu Tou. Zhang Zhimu handed the silver to Chen Yufeng, took out another ten taels, and said, "You can't ask for help from others in vain, take this too." ”

"Don't be busy, I'll talk about it when it's done, and you can just give him the door in person." Chen Yufeng said and left.

After a while, Chen Yufeng came back, and the servants went out of the city, Zhang Zhimu asked Chen Yufeng, "Are we too dark?" ”

Chen Yufeng smiled and said, "It's not dark, I'm leaving some thoughts for Lao Wu, otherwise, hum." You don't have to worry, they are doing business without capital, and they have to do it little by little. ”

"What do you mean about this?" Zhang Zhimu asked.

"These things in their hands are all stolen from the army, this old Wu guards the city gate, and he is familiar with it, so he is to pull a patron in front, otherwise he is a gate army, how can he have these things."

Back in Yaogang, Zhang Zhimu asked Liu Yun and the other three to be led by Li Yunhe from now on, and under his guidance, they began to build an iron furnace.