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On March 17, the seventeenth year of Chongzhen, Qin Mu knew what this day meant, but because Changsha was thousands of miles away from Beijing, it was impossible for the news from there to come back immediately.

What is the situation in the capital? The situation is still not according to the original historical development, even Qin Mu is not sure at this moment.

Because now the local history has changed, Jiangxi Lake has changed and has become its own territory. Sichuan has also changed, and according to the original history, it seems that Zhang Xianzhong will not capture Chengdu until a few months later.

However, according to the news just sent back, Zhang Xianzhong's gang is now progressing very smoothly, and Chengdu was conquered on February 26.

Zhu Zhishu, the king of Shu, committed suicide by throwing himself into a well with his concubines and palace maids, Zhu Zhilu, the king of Taiping, and the governor of Sichuan, Long Wenguang, the governor of Sichuan, Liu Zhibo, the deputy envoy of the imperial history, and Zhang Jimeng, the deputy envoy of the inspection, were all executed by Zhang Xianzhong because they refused to surrender.

After capturing Chengdu, Zhang Xianzhong immediately divided his troops into four routes and captured all counties in Sichuan.

At the beginning of the year, after Li Zicheng captured Hanzhong, he ordered his troops to enter Sichuan and conquer Shunqing. Zhang Xianzhong regarded Sichuan as his own territory, and as soon as Chengdu conquered it, he immediately sent Ai Nengqi to attack Ma Ke in Shunqing. sent Li Dingguo to attack Baoning; Send Sun Kewang to attack Long'an, and send Liu Wenxiu to attack Maozhou.

From this point of view, Zhang Xianzhong's entry into Sichuan has been advanced in time, so will Beijing still follow the original historical context?

Now it seems that everything is unknown.

Because everything was difficult to determine, Qin Mu felt that it was better to be still at this time.

We should pay close attention to military training and wait and see what happens.

After returning from the barracks, after dealing with the day's government affairs, he took time to go to Yuelu Mountain to teach 200 schoolchildren, because his lectures were vivid, and he would not take the children to do some interesting little experiments, and the children looked forward to him very much.

On this day, Qin Mu taught the children about the knowledge of mechanics, first of all, about the earth's gravity. He held a book and said, "Now, as soon as I let go, the book will fall to the ground, right?" ”

"Yes." The two hundred schoolchildren replied with some confusion.

"Everyone knows that as soon as I let go, the book will fall to the ground, but do you know that the book weishenme is xiangxialuo, not xiangshang?"

No one answered, and a pair of inquisitive eyes looked at him without blinking.

Qin Mu smiled and said: "The earth we live on is a circular sphere, and there are already people on the side of the Franc Machine who have sailed around the earth in a boat, which proves that the earth is round. ”

Qin Mu said this, took out a sphere prepared in advance and said: "We live on this sphere, the reason why we won't float to the sky. It is because the earth has a gravitational pull, and this gravitational force can absorb the things that the earth represents, including us, these books, houses, in short, everything is attracted by this gravitational attraction. ”

At this moment, it was like an explosion in the school hall, the children kept asking curiously, and Qin Mu patiently answered them one by one.

Children's imagination is limitless, and there are all kinds of strange problems.

There were many Qin Mu who couldn't answer, so they smiled and said, "I don't know all about the teacher. It's up to you to study and explore the principles in the future, but for any kind of thing, you can only figure out the principles in it. to use him and avoid the harm it brings. ”

"For example, this gravitational pull is good and bad for us. On the one hand, he can make us stick to the ground so that it does not fall into the sky, and on the other hand. For example, when a soldier fires a crossbow arrow, the earth's gravitational pull will suck the rocket, making the rocket's range short, making it impossible to hit the enemy at a greater distance. Of course, in addition to gravity, it is the drag of the air that causes the range to be shortened. ”

Qin Mu then took out a piece of paper and fanned it gently, the piece of paper immediately bent in the opposite direction, and he said: "Everyone sees, when we fan the piece of paper, the piece of paper will bend to the side because of the resistance in the air, so is the resistance of the air useful, yes." Look, when I push hard against the wall, it bounces off the wall, and what does this mean, it shows that the force is mutual;

The rocket uses the principle of this resistance in the air, the flame ejected from the tail of the rocket pushes the air flow, and the resistance of the air in turn pushes the rocket, just like when we push hard against the wall, the wall will bounce us out, so that the resistance in the air gives the rocket a forward thrust;

The rocket body itself will also encounter air resistance when flying, how to reduce all the resistance of the rocket body, which involves the problem of force area, if the force area of the rocket is larger, the greater the resistance it will receive, so the front end of the rocket is made into a pointed shape, which can reduce the resistance"

Qin Mu explained to the students in simple terms, and at the same time demonstrated with physical objects from time to time, which was easy for the students to understand, and Song Yingxing, who was listening, was thoughtful and seemed to have some understanding.

When Qin Mu left after class, Song Yingxing stopped him and said: "My lord just mentioned the rocket, but it reminded Xia Guan of one thing, Zhao Shizhen, who developed the Thunderbolt, in the twenty-sixth year of Wanli, once made a rocket launch device called "Rocket Slip", using this kind of rocket to slip off the rocket, which can give the rocket a certain direction and angle, improve accuracy, and this kind of rocket is easy to carry."

Without waiting for Song Yingxing to finish speaking, Qin Mu immediately remembered the bazooka of later generations, artillery casting requires a high process, and the material requirements are also very high, and this kind of recoilless bazooka used by individual soldiers is extremely simple in structure, and the casting materials and process requirements are not high, as long as the problem of artillery shells is solved, it can completely equip the army in large quantities.

"Lord Song, go to your study." Qin Mu took Song Yingxing and went to his study.

Now Ganzhou is not far from the development of yellow gunpowder, but only explosives are not enough, the current artillery is too bulky, it is still difficult to meet the needs of launching, now there is not even seamless steel, ordinary materials are difficult to withstand the pressure of yellow gunpowder, the quality of this steel is unrealistic to make a major breakthrough at once, and the bazooka is a very good choice.

After entering Song Yingxing's study, Qin Mu first asked Song Yingxing to find out the rocket slip pattern he was hiding, and Qin Mu couldn't help but be overjoyed when he saw it.

The shape of this rocket is also cylindrical, but it is much smaller than the bazooka of later generations, but according to Song Yingxing, the arrow range is much farther than that of a crossbow and a bow and arrow, and it will produce a small explosion after encountering it, but the power is limited, and the scale of the explosion is probably like a fire suddenly burning.

But in general, the principle of its launch is already very similar to that of later generations of bazookas. It's just that because it's too small, and at the same time it uses black powder, of course, the power is limited.

But if the type of rocket slip is increased, and the shells and propelled gunpowder are replaced with yellow explosives, can't there be a qualitative leap in its range and power?

In other words, with the current technology of the Ming Dynasty, there is no difficulty in making a bazooka, as long as it is replaced with yellow explosives to increase its power.

Qin Mu was so happy that he grabbed Song Yingxing's sleeve and asked urgently, "Lord Song, who did you say just now that this was invented?" ”

"Zhao Shizhen."

"Where is he? Talent, the official has to find him when he digs three feet into the ground. ”

Song Yingxing looked at Qin Mu a little strangely and said: "My lord has never heard of Zhao Shizhen, Zhao Shizhen Zhao is talented, he entered the office with the body of cloth, and the official went to the Wuying Hall during the Wanli period. He is the author of "Artifact Spectrum", "Artifact Miscellaneous", "Artifact Spectrum or Question", "Anti-Captivity Vehicle Discussion" and other treatises on the development and use of firearms. ”

Depend on! Lao Tzu really had to dig three feet into the ground to find Zhao Shizhen.

Qin Mu's face was slightly red, and he defended himself: "At the beginning, this official only asked for a gold list with a famous title, but he didn't listen to the things outside the window, and only read the sage books. ”

After Qin Mu finished speaking, he immediately brought the topic back to the bazooka, and while drawing a picture with a pen, he said: "Zhao Shizhen's rocket has given this official a lot of inspiration, Lord Song, please take a look."

Qin Mu drew the structure of the bazooka in detail, the structure of the bazooka itself is very simple, but the rocket itself is relatively complex.

"The front one is a protective helmet, and before launching, you have to take off the protective cap, pull out the fire rope, this is the warhead, and the back is the medicine chamber for the propellant, and here is the fuse, this is the roar

This is the card slot, this is the stop slot, this is the connector, and the solid spring plate is located inside here. Rotate the aiming cover so that the solid spring sheet exits the firing cylinder into the stop slot, and then retreats the aiming cover to the zuihou side of the connector, and then rotates the connector to separate the aiming cover with the connector from the rocket."

After Qin Mu finished drawing, he marked the text descriptions between the various components, and explained them to Song Yingxing one by one, in fact, except that the shells were relatively complicated, his bazooka was similar to Zhao Shizhen's rocket slip structure. Song Yingxing understood it at a glance.

Really speaking, as long as the warhead and propellant of Zhao Shizhen's rocket slip are replaced with yellow gunpowder, it is also fine, but according to the bazooka drawn by Qin Mu, it is easier to launch.

Of course, the design of the projectile and the roar of the propulsion device will also affect the accuracy of the rocket, so these improvements are still necessary.

Song Yingxing himself is also the deputy director of the General Armament Department, and Qin Mu immediately said to him after finishing the painting: "Lord Song, take this drawing to the General Armament Department for physical development and testing as soon as possible, you might as well develop a few more models, as long as individual soldiers can use them." Ganzhou should soon be able to develop a powerful gunpowder, and after your side develops it, you can replace it with that kind of gunpowder filling at that time. ”

Song Yingxing was actually also conducting research on thunder mercury here, so he naturally knew what he meant by the more powerful gunpowder, and he replied repeatedly: "Don't worry, my lord, Xia Guan will go to the General Armament Department." (To be continued......)