Mr. Lee's warning was not important to Mr. Lee.

Anyway, it's just money, don't want it in vain, especially Cheng Zhijie's money, Li Shimin won't be angry because of this.

"Iron Bull!" Li Shimin shouted to the guards beside him.

The Iron Bull Guard nodded knowingly, and walked to the gate alone.

Reaching out and slowly stroking the concrete gate, his face slightly solemn.

Where there has not been destruction, where it has been destroyed, Iron Bull has looked at it all.

He saw Cheng Zhijie's movements just now, and knew that Cheng Zhijie did not release water, especially after ten hammers, Cheng Zhijie used all his strength.

At this time, Tie Niu basically had the answer in his heart, but the emperor and those adults still needed to verify it.

Iron Bull leaned back and said in a cold voice: "Gun!" ”

A spear guard hurriedly ran forward and handed the spear in his hand to Iron Bull.

Although the iron bull is just a guard, but the qualifications are very old, more than ten years ago Li Shimin started with him, infinite strength, superb martial arts, during the period to save Li Shimin twice, if it is not for the protection of the iron bull has been coming, Li Shimin is afraid that it would have been cold, and the grass on the grave can be fed to the cattle.

So even Cheng Zhijie and the others would only say hello with a smile when they saw Tie Niu, and they didn't dare to offend.

'Bang ......'

Tie Niu used a little strength and stabbed the head of the spear into the place where Cheng Zhijie smashed it before.

The selected part is always accurate, and there is no contact with the steel bar inside, but the concrete is selected through the gap.

The moment it collided with the gate, Tie Niu only felt a huge force rebound, and it felt like hitting iron, which could not be pierced at all.

After the blow, Iron Bull left the spear with both hands.

The spear then began to slide slowly down from its tail, increasing faster and faster, until it came into contact with the ground.

"The most important weapon of the country!" Du Ru took a breath of cool air and couldn't help but admire.

"Yes, even the full force of the Iron Bull can't stand, and it's still the weakest point." Fang Xuanling also nodded.

The eldest grandson Wuji also nodded again and again, but there were still some doubts between his eyebrows: "If you use this thing to build a city, the enemy army can only use a cloud ladder, but Your Highness, do you have to use so much iron?" ”

Sun Wuji, the chief of the door here, is very clear, a small gate uses 2,000 catties of iron, if it is a city, how much should it be used?

Things are good things, but if they want to use so much iron, they can only sigh with joy, Datang can't take out so much iron to build a city, and it can't take out so much iron.

"Iron is necessary, but according to the different uses, can be appropriately reduced, the meaning of using iron is to make the concrete stronger, so that it can be closely linked, if this door wants to achieve military effect, at least five hundred catties of iron are needed, if it is less, it can only be used in another way." Li Yuanjing nodded.

Cheng Zhijie's way is to measure the degree of sturdiness, and the way of the iron bull is to consider it from the aspect of war.

The means of siege is generally to use ladders, but sometimes it is too late to make ladders, so the easiest way is to shoot thick crossbow arrows with a ballista to make them pierce deeply into the city wall, and multiple crossbow arrows form a staircase, so that soldiers can climb up to the top of the city along the crossbow arrows.

Now both possibilities have been confirmed, they can't collapse, crossbow arrows can't penetrate, and the puddles on the ground are telling them that water attacks and fire attacks don't work at all, and only ladders can break them.

However, if there is only one ladder, there are too many ways to deal with it, and if the castle is built with such a structure, it is basically certain that as long as the defenders themselves do not make fools, it is basically impossible for the enemy army to break through the city.

"In what way?" Hearing that there was a way, Li Shimin instantly became interested.

"Fence like that!" Li Yuanjing stretched out his finger and pointed to the wall next to him, and introduced: "Change the formula of concrete, remove the stones, use concrete to be responsible for bonding, fix the bricks, it can also be waterproof, if the thickness is enough, it is not easy to collapse, at least in the case of defenders, it is impossible for the enemy army to carry a sledgehammer and smash a hundred and ten times without dying." ”

This time, Tie Niu didn't wait for Li Shimin to speak, he directly took a new spear and ran to the edge of the wall to start a new experiment.

The eyes of Li Shimin and others were also attracted.

It is not easy to pierce the place where there are bricks, but it is easier to pierce the joint, but the gap is not large enough, and the spear cannot be firmly pierced, and it can barely guarantee that it will not fall, but it will fall off when you pull it with your hand, and it cannot support people to stand up at all.

"How's the yield!" Li Shimin frowned deeply, not suspicious, but thinking about other things.

It's still a bit difficult to build a city directly, but it's okay to build a new fort.

"At present, there are more than 800 people in the workshop, with a daily output of more than 4,000 bags, that is, about 4,000 stones, and this gate uses 3,000 stones of cement, and manpower is mainly used in mining limestone and crushing." The output of cement is indeed not high, and the purely manual production method is also a helpless move, Li Yuanjing continued: "Chen Miao is trying to find a way to study some new things to save manpower as much as possible, so that more people can be liberated to devote themselves to quarrying, which must be completed by manpower." ”

Li Shimin silently calculated an account in his heart, the cost of more than 800 people to eat a day is about 40 yuan, and the average cost of a stone of cement is only seven yuan, counting the wages in the later period, according to the advice given by Li Yuanjing, the cost of a stone of cement only needs about ten yuan to win.

If you build a city like the gate in front of you, you will need millions of guan, and if you build a larger city, you will need tens of millions.

But the benefits are already in front of you, even if you don't have to follow this level, you can follow the level of the wall, so that the cost is less.

Li Shimin looked at Li Yuanjing quietly: "Do you really want to give him this credit?" ”

"He researched something, and now he is still in charge, who will not give him the credit? What do you want these credits for? Li Yuanjing was a bachelor, and then said with a smile: "If the imperial brother is really embarrassed, then let the younger brother be the deputy examiner of next year's imperial examination. ”

Li Shimin looked at Li Yuanjing, raised his hand and put it down.

For a moment, he really wanted to break Li Yuanjing's head to see what was inside?

Let the craftsmen participate in the scientific expedition?

Are you sure this is something that a normal person can come up with?

But Li Yuanjing's proposal really moved Li Shimin, and there are hundreds of craftsmen in the palace, all of whom are the top in their respective industries, and their craftsmanship is naturally not to be said.

But for so many years, these people have never created anything new except for being able to do what they should do well.

On the contrary, Li Yuanjing is here, in just a few months, Quyuan plow, waterwheel, and now there is cement, I heard that he is still working on a loom, and I heard that Duhe ......

When I thought of Du He Li Shimin, I felt sorry for Du Ruhui, after he was also a hero, he was a waterwheel and a zigzag plow, although Changsun Jian spent a lot of money and didn't have any achievements now, but he was also playing high-tech.

Why did Mao do it when he came to Duhe?

Li Shimin attached himself to Li Yuanjing's ear and lowered his voice and said, "Change the direction of Du He, I can't raise my head in front of his father!" ”

Li Yuanjing smiled and loudly rejected Li Shimin's proposal: "Brother Huang, don't think that Du He is playing with dung now, he is a master when he suffers hardships, and he will be able to see the results of this summer's harvest, and if the imperial brother gives Du He a title lower than that of the county marquis, the younger brother will impeach the imperial brother in the court!" ”