The old man didn't have any shelves, and led Lu Gong and Cao Zijing to his yard.

The courtyard is not big, covering an area of less than one acre, there are few people in it, except for the master bedroom, there are only two wings, and the living room in the middle, there is a big tree planted in the courtyard, and there is nothing bright about it.

Lu Gong has seen too many big gates, especially the super high specifications of the City God Temple, even if it is the Yellow Crane and the like, there are all kinds of pavilions and pavilions, and he is still a little unaccustomed to it for a while.

In the living room, Du Chun let people serve tea, and before Cao Zijing sat down, he couldn't wait to spread the design on the table, his eyes were full of desire to learn.

Lu Gong looked at this guy, he even saved his share of tea, and suddenly felt funny at his careful thoughts.

"Lu Gong, look here. On the page of filtration devices, what exactly is the function of this drainage backwash? I've been studying for a long time, and I can probably understand that these filtration methods are to isolate dirty things from penetrating into it and achieve the purpose of cleaning with water, but I have never understood what this backwash is for. Tell me about it......" As he spoke, he waited for Lu Gong with blazing eyes, like a student who had just stepped into a private school.

Lu Gong took a look, and on the filtration device, he did set up the backwashing method, mainly after the coarse sand of the first layer, and the bamboo charcoal layer of the second layer.

So, patiently explained: "After the first layer of coarse sand filtration, the water that reaches the bamboo charcoal layer still carries a lot of fine particles, after years of precipitation, the surface of the bamboo charcoal will also produce a layer of dirt, because the diameter of the bamboo charcoal is very small, if you do not remove these in time, it is easy to be blocked, and the water can not pass, so you can only replace the bamboo charcoal regularly to solve this problem." ”

Seeing the old man nodding and seeming to understand, he continued to explain: "Backwashing, as the name suggests, is to use a water flow with a certain potential energy to clean the bamboo charcoal again and keep the aperture smooth during the daily water trough period. This eliminates the need to change the filter at all times. ”

"To put it simply, it's about increasing the service life and achieving the purpose of energy cleaning at the same time."

The old man suddenly slapped his thigh and shouted: "I see, why didn't the old man think of it?" ”

He deduced it in his own mind, and after getting the correct conclusion, he exclaimed: "What a subtlety!" Well thought out. ”

"By the way, what kind of potential energy did you just say?" The old man quickly got to the point again.

The law of conservation of energy, the conversion of kinetic potential energy, and the law of conservation of energy suddenly appeared in Lu Gong's mind, and he knew that it was too troublesome to explain this kind of knowledge, so he hurriedly brought it over,

"You can understand it as water falling from a high place, and the same amount of water, falling from a higher place, the faster the water flow, and the better the flushing effect."

Du Chun nodded and pointed to another place. "And how do you explain the water pressure here?"

Lu Gong was patient and explained to him one by one.

Du Chun seemed to be listening to a book from heaven, and after Lu Gong's repeated explanations for half a day, he finally understood most of it.

Du Chun suddenly got up and bowed deeply to Lu Gong: "What Mr. Lu Gong has learned is really embarrassing to the old man. From today on, I, Du Chun, would like to hire Mr. as a guest to add luster to my Dahua Dynasty, I don't know if it can be fulfilled? ”

Lu Gong was startled, and Cao Zijing's mouth was slightly open, a little incredulous.

A simple drawing can make the dignified Ministry of Engineering Shangshu such a gift!

Looking at the old man's sincere appearance, Lu Gong felt a little lost in his heart. "Lord Shangshu, if you don't want Lu Gong, you really can't. What the younger generations have learned is not at all about helping the world and saving the people, but only some superficial knowledge. Moreover, the real stubborn disease today is not in these crafts, but in the atmosphere of the two ways of man and god. If this trend does not change, relying on these strange tricks will not help at all. ”

Du Chun's face suddenly changed slightly, he stared at Lu Gong for a long time, and suddenly sighed, as if all the spirit and spirit had disappeared in an instant.

Cao Zijing listened beside him, closed his eyes slightly, and acted as if he hadn't heard anything.

"I heard that you have done a lot of great things in Tianshui County, and you are quite respected by the local gods?" Du Chun suddenly changed the subject.

Lu Gong didn't know why he suddenly talked about this, and responded: "I can't talk about big things, it's my honor to be able to trust the gods of Tianshui County." ”

Du Chun sighed and glanced at Cao Zijing, obviously not very trusting of this judge of Si Tianjian.

"In the future, don't be too impulsive. Especially for the yin division everywhere. If you were happy to take revenge three years ago, as long as it makes sense, the world would be on your side. And now, everything must be based on the general righteousness and take into account the overall situation. The golden body of the city god is the most important thing for the imperial court in the past three years, and it must not be an enemy of the general trend. Du Chun seemed to say it to Lu Gong, but in fact, it was also said to Cao Zijing next to him.

When Lu Gong heard this, he couldn't help but smile and said: "Justice is in the hearts of the people, even if it is the law of Si Tianjian, I don't believe that it can withstand the mouths of the people." ”

Du Chun shook his head slightly. "You'll figure it out in your time."

Lu Gong could see the helplessness in the old man's eyes, but he couldn't agree.

This time to Kyoto, it was nothing more than two things, and now the first thing has been completed, and only Lin Ruopu remains.

Lu Gong didn't want to delay time, so he said directly: "My lord, how are we going to deal with Lin Ruopu's matter next?" ”

"There's no hurry!" Du Chun said softly.

"Not in a hurry?" Lu Gong was a little surprised, this is your old man asked me to come to Kyoto, and now everything is ready, so he said that he was not in a hurry.

"Lin Ruopu's matter can be big or small, but the final decision is not in the Ministry of Industry." Du Chun said.

Lu Gong was depressed. "If he's not in the Ministry of Works, then who can convict him?"

Du Chun suddenly smiled and said: "Lin Ruopu's matter, in fact, the entire Ministry of Industry knows it. It's just that now that several forces are competing, there has not yet been a result, and we can only wait now! ”

Lu Gong was slightly angry. "To deceive is to deceive, and to put it mildly, this is the sin of deception. Is there room for manoeuvre? If so, what's the point of me coming to Kyoto? ”

"Hahaha......" Du Chun suddenly laughed: "Of course it makes sense." With you, the forces behind Lin Ruopu will have to pay a greater price if they want Lin Ruopu to continue to stay in the Ministry of Industry. On many things, they have to compromise. So, Lu Gong, it is very important for us that you stay in Kyoto! ”

When Lu Gong heard this, the anger in his heart became more and more vigorous, and his tone gradually became less polite.

"According to what your lord said, I am also one of your pawns?"