Only then did everyone suddenly realize that if it was really according to what Su Ziheng said, as long as the pass was built in a dangerous place to prevent the enemy from attacking on a large scale, and there was a crow army in the territory to protect it, there was indeed no need to build a city wall.

"Lord Changshi, is there anything else you don't know about the lower officials?" Zhao Chengming continued to ask.

"Please."

"According to Lord Changshi, the north of Donghai County is the stretching Donghai Mountain Range, which is a natural barrier, and then we only need to set up a beacon tower at the highest point on the mountain. A little fortification can prevent the enemy from breaking through. ”

Su Ziheng nodded and said: "Yes, I have this intention, not only is there a mountain range in the north to block it, but there is also a sea in the east as a barrier, and it is almost impossible for the enemy army to launch a large-scale attack from these two sides." ”

Zhao Chengming said: "The west side can rely on the mountain to build a solid city pass. But what about the south? Although there was a large river as a natural danger, it could not prevent the enemy from landing by boat. ”

"Although the river is dangerous, it is still not as good as the sea. A little bit of water can land smoothly from the river, and if you want to build a wall along the river bank, the project is also huge. ”

"It's okay," Su Ziheng waved his hand and said: "I've already thought about this, we don't build city walls along the river, we build river embankments." I've investigated that the river floods farmland every year during the flood season, and we need to build a tall and strong embankment to prevent it. Now it's just a matter of heightening and fortifying it, setting up pillboxes in places where it's easy to land, and holding back the enemy. ”

According to Su Ziheng's plan, if the embankment along the river was reinforced and raised to more than ten meters, it would be almost the same as a city wall, and he didn't believe that someone with a vertical embankment of 90 degrees could directly climb ten meters high.

What's more, because of the back of the river, the enemy can't even set up a ladder. When the time comes, cannons will be erected along the embankment, and batteries will be built in the same direction as the east facing the sea, and no warship will try to approach it easily.

In addition, Donghai County is also developing its own navy, and when the steam engine is invented, it will be installed on an iron steamship, and then there will be that navy that is the opponent of the Donghai County Navy? Not to mention anything else, the iron boat can drive over and sink the opponent's wooden boat directly.

After listening to Su Ziheng's plan, Zhao Chengming finally breathed a sigh of relief, and let out a long breath: "If this is the case, then there is no doubt about the lower officials." Later, after the meeting, Xia Guan took the surveyors to reconnoiter the western terrain, striving for the next few days to design the architectural drawings and ensure that the western part of Donghai County would be built into an ironclad pass. ”

Su Ziheng said happily: "That's great, don't worry about materials and manpower, you just let it go, and I'll deal with the rest." I want you to make this pass a majestic pass that will not be broken for thousands of years. ”

Zhao Chengming said with a straight face: "Yes, Lord Changshi!" ”

……

……

After the discussion of the construction of the city, Su Ziheng began to ponder the question of how to release the labor force.

At present, nearly 20,000 of the 80,000 people in Donghai County have left, and there are nearly 50,000 people, and a small half of the labor force is engaged in heavy manual labor such as stone mining, road construction, and carrying raw materials.

In particular, mining and transporting stone is a waste of manpower. However, it is not possible to build all kinds of buildings without stones, and there are typhoons in Donghai County every summer, and many buildings are easily damaged if they are not built with such a strong raw material as stone.

Rather than this, it is better to work hard at the beginning, directly in one step, and save the future repair.

He had been running around before, and Su Ziheng didn't settle down and think about how to solve these things. Now it's different, it's stable internally and externally, and you don't have to go out for at least a few months.

Su Ziheng planned to take advantage of this time to invent the steam engine, with the steam engine, so simple manual labor can be handed over to the steam engine to deal with, especially the transportation of stones.

When the time comes, the railroad tracks will be erected, and the steam train and steam car will be taken out, and there will be no need to worry about transportation.

The so-called steam engine is a reciprocating power machine that converts the energy of steam into mechanical work, and it requires a boiler that boils water to produce high-pressure steam, which can use wood, coal, oil, live natural gas and even combustible as a heat source. The steam expansion pushes the piston to do work.

On the earth in Su Ziheng's previous life, the appearance of the steam engine caused the industrial revolution in the eighteenth century.

At this time, Donghai County, or the entire continent, may not have reached the point where technology and industrial technology could make steam engines.

But for Su Ziheng, none of this is a problem. He has several sets of encyclopedias with detailed manufacturing methods. As for the level of craftsmanship, he is not afraid, at most the key places will be handled by Pandora, and he is not going to mass produce now, so it should not consume much base energy.

In the previous life, the steam engine was perfected from its appearance to the end, but it has gone through hundreds of years of development history, during which it has been continuously optimized and improved several times, and finally improved by Watt to become the most commonly used steam engine.

The improved steam engine can be widely used not only in the mining industry, but also in smelting, textile, machine building and other industries.

What Su Ziheng intends to build is this kind of steam engine that has been formed and widely used.

He first found the method of manufacturing the steam engine in the encyclopedia, and found that the steam engine was mainly composed of cylinders, bases, pistons, crank connecting rod mechanism, slide valve distribution mechanism, speed regulating mechanism and flywheel.

After Su Ziheng printed out the drawings, he then summoned all the people in charge of the craftsman's workshop and distributed the drawings in his hands accordingly.

He carefully advised: "You are all old men who have followed me all the way from Xining, and the next thing I want to do is the top secret of the craftsman's workshop. ”

Su Ziheng looked around at everyone in the conference room, and couldn't help but smile when he saw everyone's solemn expressions and attentive listening to the lecture.

"This is a magical mechanical blueprint given by the dragon god, and as long as we can make it, it can replace many laborers. I've already distributed the drawings to you, so let's see if you can build them with the tools you have. ”

"Yes, Lord Changshi." When everyone heard that this was a drawing given by Lord Ryujin, their movements immediately became much lighter, for fear of breaking it.

"In addition, these drawings are not allowed to be leaked privately, and you are not allowed to communicate without permission in private, if there are any problems, discuss them together during the meeting, do you understand?"

Although it is said that these drawings are leaked out, people outside may not be able to make steam engines according to the drawings, but he can't guarantee that there is really a genius like Lu Ban.

"Obey the orders of Lord Changshi."