Listening to Wu Sangui's words, Ni Yuanlu was a little shocked, not surprised by anything else, but very interested in what Wu Sangui said about the hollow cannonball skin containing flint and gunpowder. As for what lime bombs, shit bombs, and chili bombs are talking about, only a half-sized kid like Wu Sangui can think of it, and what kind of psychedelic powder, sneezing medicine, soft tendon powder, etc., are not better than being put in the skin of a cannonball? The idea of containing gunpowder and flint in the skin of a hollow cannonball gave Ni Yuanlu great inspiration.

At the beginning, the cannon was made of cast iron barrel, and when it was used, it was first loaded with gunpowder at the bottom of the barrel and pressed, and then an iron lump was placed on the top, and the gunpowder in the barrel was ignited by the lead to produce a violent explosion, and finally the iron lump at the front end was thrown out to hurt people. The principle of this cannon is to restrain the explosive force of gunpowder to one direction, and its biggest hidden danger is that it is easy to explode, as long as the cannon is damaged, the cannon will be scrapped, and it will have a negative impact on the psychology of the gunner. When a soldier fights a war, he tries to kill the enemy and make meritorious contributions, and when he fires artillery to hit the enemy, he first fears that he will hurt himself, and no one will be happy to change it.

There are many reasons for the explosion, the most important is the material of the barrel, because pig iron is relatively brittle and easy to crack after being stressed. Gunpowder is not as obedient as people, it has no directionality when it explodes, and the barrel and base have a binding force on the gunpowder explosion, and the gunpowder explosion has a counter-binding force on the barrel and the base, because the force is mutual. The power of the gunpowder explosion is so great that it will only be released after the force sends the shell out of the barrel, and if the barrel itself can no longer withstand the counter-restraint force before the explosion is released, the explosion is inevitable.

The most convenient way is to thicken the barrel to make it not easy to explode, for example, the tiger squat cannon is that the barrel wall is thicker than the muzzle, the thick thigh body of the cannon body, the big orange eyes are very strong, how to fall and how to use it is not easy to break. But the cannon hole is too small and the power is not great, the tiger squat cannon can also make the enemy see some blood or even wear a hole when the enemy is close, and the distance is far away, and the most it will be swollen on the body. If you want to be powerful, hurt a lot of people, and hurt people ruthlessly, you have to load a large bullet and use fierce medicine, and the problem is that if you want a big shell, you have to increase the cannon hole and thicken the barrel, and take the example of a tiger squat cannon to make a cannon with a large human head, and you have to grind the gun body, and you can't do it at all.

When the cannon body is larger and heavier, the transfer of the cannon becomes a problem, and there will be many conditional obstacles to launch, so everyone is thinking about how to reduce the cannon body without reducing the power of the cannon, and then they will focus on the copper cannon. Compared with pig iron, the toughness of copper is much better, even if the barrel is blown up, it is not easy to hurt people, and the copper cannon also has the advantage that the internal processing of the barrel is convenient. In addition to the brittle material, there is also a reason that the inner pipe wall is not smooth, which will produce resistance, pig iron is harder and more troublesome to process, and copper is softer, where is wrong, it is easy to file and grind.

The advantage of copper is that it is relatively soft and easy to process and has good toughness, but this is also its disadvantage, the inner chamber of the barrel will be deformed after two cannons, and if it continues to be used, it will even make the barrel deformed seriously and cannot be put into the shell, so that the cannon will be scrapped. Ni Yuanlu once heard from Tianqi in Wang Gongchang's suggestion to use coke to smelt refined iron to make a cannon, and also said that the cannon body rotated with a hard knife to process the inner wall to make it as round as possible, but these were only ideas and could not be used, because the power to continuously rotate the cannon body had not been found. Refined iron is generally very hard and very difficult to process, and after processing, it is more advanced than pig iron barrels, but it is limited, but it is only used for a longer time.

Over the past two years, Ni Yuanlu has made cannons of different materials and different thicknesses, such as fine iron cannons, bronze cannons, pig iron wrought iron combined cannons, etc., and compared with each other, it is found that there is still no way to meet the requirements of cannon miniaturization, that is, under the premise of undiminished power, let the cannons on ships and carts, so that the Ming army can move quickly and quickly arrange cannons to kill and injure the enemy. During this period, the silver cost more than 100,000 yuan, and the two people also requisitioned a lot, so that the ministers of the DPRK and China shook their heads, although Tianqi did not blame him clearly, but let Sun Yuanhua and Mao Yuanyi replace him, and asked to operate through the Evergain Company, which also shows that his confidence in Ni Yuanlu has been shaken.

Now Wu Sangui suggested that the cannonballs be made into jars, which contained pepper lime gunpowder or something, which made Ni Yuanlu think that if this jar was regarded as a cannon, it could solve the problem that the barrel would explode if the barrel was thin. The iron cannon barrel is easy to explode but not easy to deform, the copper cannon barrel is easy to deform but not easy to burst, put the copper cannon with the cannon barrel and the cannonball into the iron cannon barrel together, and ignite the gunpowder in the copper cannon barrel after the shell is fired along the iron cannon barrel, so that the iron cannon barrel can be made thinner, because it does not directly bear the anti-binding force of gunpowder, and the copper cannon barrel can also be made as thin as possible, because I am not afraid that it will be deformed and changed to another one.

Seeing that Ni Yuanlu pondered for a long time and didn't speak, Wu Sangui asked, "Uncle Ni, what's wrong with you?" You think there's a problem with the idea of lime bombs, shit bombs, and pepper bombs, right? ”

Ni Yuanlu suppressed his excitement, took two breaths and said: "I think your ideas are very creative, I don't comment on whether they can be successful, it's best for you to make them all one by one." ”

Wu Sangui said with a smile: "The little nephew just thinks like this, how can he have the ability to do it?" Even if you can find a craftsman to help, you don't have so much silver to throw around, Uncle Ni, you have prestige and are very appreciated by the emperor, thousands of taels of silver can be reached out casually, isn't it good for you to do it? ”

Ni Yuanlu said: "Now that the emperor uses the Evergain Company to operate all the armaments research, I am sure to use your suggestion to apply for silver, whether there is at least 10,000 taels is certain, and when the time comes, we will spend 3,000 taels per person and 4,000 taels for the craftsmen to do it, do you see if you are interested?" ”

Wu Sangui listened to one of his suggestions and could get three thousand taels, and suddenly opened his mouth wide in surprise, and he stammered and asked, "Uncle Ni, you're not joking, are you?" I also know that the emperor has a lot of money, but he can get three thousand taels with one idea, and the emperor's silver is too easy to take, right? ”

Ni Yuanlu said: "The emperor won't do a loss-making business, and you don't have to care so much, just say if you are willing to come and do it with me?" ”

Although Wu Sangui was only seventeen years old, his father Wu Xiang was a very smart person, Wu Sangui received his father's education since he was a child, and knew that everything in the world has good and bad. He thought for a while and said, "Uncle Ni, don't talk about good things first, just talk about what you want your little nephew to do." ”

Ni Yuanlu nodded and said: "You will know how to do it at that time, but you must understand one thing first, that is, once you decide to follow me, you can't be half-hearted, you can take the martial arts test if you want to, but it is impossible to go to the front line to fight, you have to think about it before deciding." ”

Wu Sangui asked, "Why is that?" There are also many people who come in and out of you, and you are not allowed to leave until anyone comes in. ”

Ni Yuanlu said: "People who come in and out at any time are people who have not been exposed to important technology, and you can easily see people who really know important technology. If you decide to do it here, I can immediately write to the emperor that you have your credit in it, but once the emperor knows about it, you can't leave if you want to. ”

Wu Sangui asked: "Since I should be rewarded for my merits, why would the emperor not let me go and lock me up?" ”

Ni Yuanlu said: "Because this thing may become a secret related to the fortunes of the Ming Dynasty after it is made, don't say that the emperor even I will not allow unrelated people to know this." You start lifting grenades, but you know what, there are only two people who know exactly how grenades are made, and there is one other person besides me, and he and his family are placed in a very safe and very secluded place. The emperor said what the family needed to meet as much as possible, but once they found that they had signs of escaping, they immediately cut it down and left no trouble! ”

Wu Sangui cracked his mouth after hearing this, as if he was smiling bitterly and as if he wanted to say something but couldn't say it, Ni Yuanlu said: "I also know that you are embarrassed, or you can ask your father before deciding, don't you decide easily, and he will blame me when the time comes." If you want to stay, don't think about being happy outside, if you want to leave, leave as soon as possible, and forget about it and don't mention it in front of anyone else, or the guards and brocade guards will come to you for trouble. But let's talk about it first, whether you decide to stay or leave immediately, as long as there is a reward, the three thousand taels I promise you will not be less, but the name given to you is different. ”

Wu Sangui thought for a while and said: "Uncle Ni, your benevolent and righteous little nephew admires, it's better for my father to have an idea about this matter, I just wonder if you can say it, Uncle Ni, why didn't the emperor lock you up?" ”

Ni Yuanlu said with a smile: "It's not strange because I am a scholar and a jinshi, the emperor said that only scholars and eunuchs who have read sage books since childhood are trustworthy, there are only two ways for you to get in touch with these things, one is to read and take the examiner to take the jinshi, and the other is to emasculate yourself into the palace, you see which way you choose?" ”

Wu Sangui hurriedly said: "I don't want to choose either, I have a headache when I read the book, or just take a martial arts exam, and the second road can't be walked, my father said that the old Wu family still expects me to pass on the lineage and spread the branches." Since this matter is so evil, then there is no need to wait for news from my father, the little nephew has decided to leave tomorrow now, riding a horse and dancing a knife to make contributions on the battlefield is what a good man should do. ”

After Wu Sangui left, Ni Yuanlu was ready to tell Tianqi about his idea of making a child and mother cannon, and as soon as he picked up the pen, he remembered that something was wrong, that is, he hadn't come up with a way for more than two years, and the emperor just said that the method of giving money would be drilled out immediately, would the emperor think that he had a way not to say that he was counting on silver?