The son fooled himself, and his subordinates were ready to fool him, and the little eyes that glanced back and forth clearly indicated that it was related to Li Chengqian, which made Lao Li how not to be angry, how not to be angry.

But just when Li Er was about to be furious, Li Chengqian came up with a ghost and said in a low voice: "Father, that's an iron roller for grinding charcoal, it's useless, you misunderstood." ”

It'......s just an iron roller, Li Er's expression froze for a moment, and he took a deep breath to suppress the anger that had just risen.

It's so embarrassing, I thought this was some kind of secret weapon or something, but I didn't expect it to be an iron roller with the same effect as a grinding disc, but fortunately I didn't say anything just now, otherwise this face would be even more embarrassing.

But the hell that bastard put this thing here? When you go back, you must find this person and rectify it well.

Li Erru thought about it, and was about to find another topic to divert this paragraph, Li Chengqian whispered beside him: "Father, if you want to see something new, this will really be one in the prison, but that thing is still being studied, the technology is not very mature, and there is still a distance from the finished product." ”

The embarrassed Li Er thought that this was a topic that Li Chengqian was looking for in order to save his face, and glanced at him very approvingly, then pointed to the trench car and asked casually, "New things?" How about this? ”

Li Chengqian described the trench cart used to cross the moat and the trench with disdainful eyes, and said in a tone of smugness and some contempt: "This is not comparable, the trench is just a tool to assist the attack, and that is the weapon used for the real attack." If the research is successful, it will be far more powerful than bed crossbows and trebuchets, trench carts, ...... toys. ”

"Slap", a big slap slapped on the back of Li Chengqian's head, and Lao Li grimaced: "If you dare to talk to Lao Tzu in this tone again, beware of me discounting your legs." Let's go, go see what you're talking about, I'd love to know if there's anything more powerful than a bed crossbow and a catapult. ”

"Uh......" Although he was beaten, Li Chengqian knew that this matter should have been revealed like this, and the old man should not mention it again in the future, so it should be considered a good thing in general.

Thinking of this, Li Chengqian, who was a little depressed, was in a better mood again, gave Liu Min a look, motioned for him to lead the way, and then followed the old man and pretended to be a calf.

After going around several times, Li Er, Li Chengqian and his entourage were taken by Lao Liu to a very hidden small courtyard, and when they entered, they saw seven or eight people arguing about something around a pipe made of cast iron.

"Your Majesty is here ......" The old eunuch Fang behind Li Er couldn't help but roar when he saw that those craftsmen were too involved in arguing and ignored His Majesty the Emperor.

"Okay, okay, I'm just going to walk around this time, don't get these formal things." Li Er waved his hand at the old eunuch, and then asked the craftsmen who gave him a salute, "What are you arguing about?" What is this tube? ”

"Back to Your Majesty, this tube is called a cannon tube." A craftsman in his fifties said worriedly, and it seemed that he should be in charge of the project.

But maybe it's because of social status or something, in front of Li Er, the old craftsman was a little trembling, and his speech was a little messy, and he didn't explain it to Lao Li for a long time.

In the end, Li Chengqian said: "Father, you can treat this thing as a super-large handcuff, that's it." ”

"Oversized handcuffs......" Li Er thought about it, lowered his head and took out his handcuffs from Li Chengqian's waist, and after looking at them for a long time, he didn't find anything in common with the cast iron pipe and the handcuffs.

"Father, the principle of these two things is the same, what they are different about is only the appearance, but because this 'cannon' is mainly used in siege, it needs a lot of gunpowder, so the pipe will be made so big." Li Chengqian saw the old man's confusion and continued to explain.

"So what are they arguing about?" Li Er asked.

"The material is not up to par, because the amount of gunpowder increases, so the explosive force will be particularly large, which requires the outer iron pipe to have a certain strength, but also a certain hardness and stiffness. However, at present, the quality of our steel is only up to the hardness standard, which means that the current pipe will not be deformed even if it is placed here for thousands of years, but it is not malleable enough at the moment of gunpowder explosion, and the final result is often that the barrel is burst. ”

Many of what Li Chengqian said were some technical terms in materials science that would only appear in later generations, and listening to Li Er's ears was like a duck listening to thunder, and he couldn't understand it at all.

But fortunately, Li Er has a very good quality, that is, he is not ashamed to ask, so Li Chengqian had to explain to the old man what strength is, what is stiffness and hardness.

Good hardness is the ability of solid materials to be permanently deformed, for example, iron can be bent and deformed, but glass cannot, so the hardness of glass is higher than that of iron.

Stiffness refers to the ability of solid materials to resist deformation, or if you compare iron with glass, iron can resist a certain degree of deformation, but glass is not, as long as it is slightly deformed, it will be completely broken.

Strength refers to the ability of solid materials to resist damage, just like iron can be smashed with a hammer, even though it will be deformed, but it will continue to shatter, but glass cannot do this, so the strength of glass is not as good as iron.

Li Chengqian majored in chemistry, and he didn't have much understanding of materials science, so it was a bit laborious to explain it in conventional language, but fortunately, the old man had a good understanding ability and roughly understood something.

He wouldn't have designed anything himself, anyway, so a simple understanding was enough for him to figure out the current situation.

But from Li Chengqian's introduction, Li Er also heard some extraneous sounds, and to sum it up, it should be that this thing called 'cannon' seems to be extremely powerful, and it is so big that it is beyond the comprehension of ordinary people.

"Father, you happened to be here today, and you also know the difficulties faced in studying this thing, so can you ......" Li Chengqian made a gesture of rubbing his fingers.

Li Er knew that this was asking for money, and Li Chengqian had made the same gesture to him before, but Lao Li was not a fool, so he would not pay for an inexplicable thing.

A guy like Li Chengqian, who tinkers with some strange things from time to time, if he asks about the specific usage and use of things, God knows what he will come up with in the end.

Li Chengqian waited for a while, and saw that the old man had been silent, and couldn't help but be a little anxious: "Father, it's just 10,000 guan, as long as 10,000 guan, and what can 10,000 guan do now?" You can't do anything, can you? It's different if you can invest here, as long as you research something, you will have an invincible and invincible weapon in your hand. ”

"Fart, that's 10,000 guan, it's not consistent, is it really impossible to do anything in your eyes?" In response to Li Chengqian's nagging, Li Er finally had a hint of reaction, but this reaction seemed to be a little intense.

(End of chapter)