The case was solved and all the prisoners were arrested. In addition to the eight people Li Jie and the others caught, there was another person hidden among the beggars and was soon found out. As for the coerced Fang Zhanggu, although he had a crush, he violated the national law after all and should have been punished. However, Li Jie begged for him in front of Zhu Biao, but in the end he just gave up his official position and asked him to take his grandson home to retire.

On the surface, the case seemed to be over, but Li Jie was not happy at all. The Yinku was designed by him personally. He used so much cement and thought it would be impregnable, but he did not expect that this helped the tomb robber to teach him a lesson and demonstrated that he used the original thermal expansion and contraction to destroy the Yinku wall without so many tools in later generations.

If Zhu Xueqing hadn't been careful and discovered the conspiracy of these people early, at most, the walls of the silver deposit would be chiseled open by them in two or three days. This also means that the silver deposit was not as strong as Li Jie thought. Although they stopped this time, God knows if there will be a next time. If someone succeeds, it will be a heavy blow to the bank.

"Xueqing, do you have any good solutions?" In the silver vault, Li Jie looked at the repaired wall and asked Zhu Xueqing next to him in a deep voice. The big pit outside the wall had been repaired, but the hidden dangers still exist.

"I don't have any good solutions. The only way now is to strengthen the bank deposit again, but this will not cure the root cause!" Zhu Xueqing also frowned and said.

"It's a pity that if metal is used to build a silver vault, there is no need to worry about this problem!" Li Jie also sighed at this time. If metal is used to build a silver vault, it is probably impossible to break the wall with the technical means of this era.

"Brother-in-law, you dare to think too much. Although our bank has money, it cannot be ruined like this. Even if we use cheap pig iron to build such a large bank treasury, our bank may not be able to support it!" Zhu Xueqing said speechlessly when she heard Li Jie's words.

Actually, it’s not that Zhu Xueqing cannot understand, because the metals during the Ming Dynasty were too expensive. For example, taking iron as an example, based on purchasing power, the price of iron in the Ming Dynasty may be dozens of times, or even hundreds of times that of later generations.

After all, the steel output in this era was too low. Smelting was done by man-made and the raw materials were very expensive, which led to the high price of steel, which was impossible to be as popular as in later generations. For example, when later generations used cement, they liked to add steel bars. However, Li Jie was reluctant to use steel bars at all to build this silver warehouse, otherwise the tomb robbers would not have destroyed the walls so easily.

"If it really doesn't work, buy all the land near the bank and isolate it out of an area. After all, the tunnel cannot be dug too long, so it should be safer." Li Jie suggested at this time.

"This method is good. In addition, you can also set up some early warning devices around the bank vault to monitor the situation underground. If someone really digs the tunnel, we can also know in advance!" Zhu Xueqing also made her own suggestions at this time.

"A warning device? How to warning underground?" Li Jie also showed a puzzled look when he heard this.

Unexpectedly, Zhu Xueqing burst into laughter at this time, and then she finally stopped laughing and said, "I thought you knew everything, brother-in-law, but I didn't expect that there was something you didn't know in this world!"

"I'm not a god, how can I know everything? Tell me quickly how to warn others to dig tunnels below?" Li Jie first laughed awkwardly, then asked again.

"Okay, since you don't know about brother-in-law, then I will tell you. Actually, I learned this method from the army..." Zhu Xueqing said this and smiled and told the so-called early warning device.

The so-called early warning device actually burys some large urns half-buried underground with the mouth facing upwards. If there is any movement underground, it will be magnified by the urn, so that people on the ground can easily detect movement underground.

This method was originally a way to defend the city in the army, because when defending the city, the most feared thing was that the enemy digs tunnels into the city. So someone invented this method. The urn buried underground is actually a sound amplifier, which can amplify the sound underground, so that it is easier to detect the enemy's actions underground, and thus prepare in advance.

"So that's it. I didn't expect that there was such a skill in the army!" Li Jie said in surprise after hearing this. It was the first time he knew this method, and he had to say it was very exquisite.

"Actually, there are many practical methods in the army. I heard it before..." Zhu Xueqing was a little excited, but when she said this, her face suddenly froze and she didn't say anything else.

Li Jie immediately reacted when he saw Zhu Xueqing's expression change. Zhu Xueqing had never been to the army. She shouldn't actually know these methods. The only possibility was that she had heard from her father Zhu Chuang before that although Zhu Chuang had been demoted to Japan for a long time, whenever Zhu Chuang's name was mentioned, Zhu Xueqing was still a little unable to let go.

"Xueqing, everything before has passed, and it is almost impossible for him to come back after he went to Japan, so you don't have to worry about him anymore!" Li Jie whispered at this time.

Unexpectedly, Zhu Xueqing smiled faintly and said, "I know, I have let go of the past. No matter what he said, he is my father, and he has paid the price for what he has done. Now I no longer hate him. I hope he can live a better life in Japan!"

"He has lived a pretty good life in Japan. Now he has almost become the overlord of Japan. Although the names of Japan hate him to the core, they are not as good as others. Now they can only unite together and barely protect themselves." Li Jie also said with a smile. He was still very concerned about the situation on Zhu Ren's side.

"He has always been a proud person. If he can't handle the little Japanese country, he may not have the face to see Grandpa the Emperor again." Zhu Xueqing was not surprised when she heard this. In the past two years, she tried not to inquire about Zhu Ceng's situation in Japan. It was the first time she heard about these situations.

"By the way, didn't the Fourth Uncle join forces with Zhang Dingbian and others to find the legendary America? Did he participate in it?" Zhu Xueqing asked again at this time. It was rare that she was in the mood to inquire about Zhu Chuang's situation now, so she just asked more so that she could know more.
Chapter completed!