The stones flew out and smashed into the ground, not only hitting a large crater at the landing site, but also rolling forward for a while before stopping.

The first trebuchet experiment was very successful, looking at the damage caused by the stones, Ye Xiao was very satisfied, with the first manufacturing experience, the next imitation was very simple, Ye Xiao told Zhao Yun to take charge of this matter, and he didn't care about it anymore.

Compared to making trebuchets, Ye Xiao has a more important thing to do, and this matter is also what he attaches the most importance to, if it can be successful, then the development of their Kunshan tribe will be far ahead of the forefront of this world.

This thing is to make black powder, and when it comes to making explosives, how can you not have the ghost doctor, a demoman.

No one knows how to make explosives better than him, and black powder is one of the four great inventions of China, which is the crystallization of the wisdom of the ancients.

The material used to make black powder is simply one nitrate, two sulfur and three charcoal, and these three things are mixed together according to a specific ratio to make black powder.

Nitrate refers to potassium nitrate, which can be obtained from saltpeter, they don't have saltpeter available now, but there are two other methods of soil that can be obtained, one is extracted from the soil under the corner of the old house, and the other is obtained from human and animal manure. There is no old house, and now it seems that there is only one way left, although it is disgusting, but it is nothing to Ye Xiao and them.

Disulfur refers to sulfur, and there are many ways to refine sulfur, and natural sulfur in nature is generally the most abundant in volcanic craters, so finding volcanoes has become their most important task.

Santan refers to charcoal, which is the most readily available raw material, and there are many trees here, so it is enough for them to cut down two trees and burn them into charcoal.

From this day on, the daily excrement of the Kunshan tribesmen was collected and placed in a centralized manner, although they didn't understand what Ye Xiao was collecting these things for, but the patriarch's order was there, so they could only cooperate.

Because of the cold weather, the excrement is easy to freeze into ice, Ye Xiao dug a cave far away from the settlement, and dug a big pit in the cave, all of which were poured into it, and fires were burned on both sides of the cave to maintain a certain temperature in the cave.

Ye Xiao built another earthen kiln to burn charcoal, and while preparing materials for making black powder, Ye Xiao did not relax in training those soldiers, but fortunately, there were seven of them, and the division of labor and cooperation were still busy.

……

In the past few days, Ye Xiao has been intensively making the materials needed to make black powder, and the first furnace of charcoal has also been fired, and Ye Xiao has asked people to grind them into powder little by little.

Another important material, potassium nitrate, has also been extracted from a large amount of excrement by ghost doctors through some means, but because the content is small, the amount extracted is not much.

It's just that the third indispensable material, sulfur, is not at all, and there is no news from the people sent out to find the volcano, which makes Ye Xiao a little difficult, without sulfur, they can't make black powder, so their preparations will be in vain.

What to do? It is impossible to give up, there is no word give up in Ye Xiao's dictionary, if you can't find the volcano, then you can only think of other ways.

Five days later, the people sent out to find the volcano came back and brought back the news to Ye Xiao that they had found a natural hot spring in a valley more than a hundred kilometers away from here.

Although it was not a volcano, it also surprised Ye Xiao, because according to the descriptions of these people, the hot spring pool exuded a very pungent smell, and there were some yellow objects on the edge of the pool, Ye Xiao guessed that this was probably the crystallization of sulfur.

Hearing the news, Ye Xiao immediately rushed to that valley with the ghost doctor and Pan Zi. When they came to the mouth of the valley, Ye Xiao smelled a pungent smell, which made Ye Xiao even more sure that there was the sulfur they were looking for.

Ye Xiao asked the rest of the Kunshan tribe to wait outside, and after taking protective measures, Ye Xiao, the ghost doctor, and Pan Zi walked in.

The temperature here is a little higher than the outside, and there is no snow in the valley, so it is supposed that the hot springs release heat to melt the snow, and since there are natural hot springs, there must be geothermal activity underground, and there may be a lava tunnel not far from the ground.

However, this kind of place should be very stable, and the lava will not easily erupt to the ground, and not long after walking inside, Ye Xiao and the others saw large and small pools scattered everywhere, the water surface was steaming, and the color of the spring water was also a little abnormal.

Ye Xiao walked to the side of a pool, looking at the bubbling hot spring water, he didn't try it with his hands, people with a little common sense know that there is a smell of sulfide here, then the water must also be integrated with various sulfides, this pool water must be acidic and corrosive.

There are a lot of yellow-brown crystals next to the pool, Ye Xiao carefully collected them with tools, the ghost doctor and Pan Zi are also doing the same, these yellow-brown crystals are the crystals of sulfide, take them back and get some sulfur powder through some methods.

Ye Xiao didn't know how to extract sulfur from these sulfides, but the ghost doctor just understood, and the collection was almost done, and they retreated without staying too long, because the smell of sulfide here was too strong, even if they did protection, they could smell it.

Moreover, they know that this smell must contain hydrogen sulfide gas, which is poisonous, and hydrogen sulfide poisoning is not a joke.

After all, the equipment is too rudimentary, if you give them a set of chemical protective suits, no, in fact, you don't need chemical protective suits, even gas masks, then these pungent smells will not matter.

After collecting some of the sulfide, Ye Xiao and the others withdrew to the Kunshan tribe, but before leaving, Ye Xiao had the entrance to this valley sealed, which would be an important source of sulfur for them to make gunpowder in the future.

At the same time, Ye Xiao also had some regrets, if it weren't for the fact that the hot spring water was rich in sulfide, he really wanted to go in the hot springs, natural hot springs are rare, on the earth, most hot spring places are under the guise of natural hot springs, in fact, those hot spring waters are artificially heated.

Back in the Kunshan tribe, Ye Xiao and the ghost doctor began the process of preparing black powder, gunpowder is a very dangerous thing, for which Ye Xiao specially built a laboratory, which was built in a hidden cave in the back mountain.

For the sake of confidentiality and security, Ye Xiao did not tell others, and only a few people knew that there was such a laboratory in the back mountain.

The road leading to the back mountain also allowed Ye Xiao to send people to guard it, and idle people were not allowed to approach, even if Lan Heng and Lan Xue wanted to go in, they had to agree to Ye Xiao.

The ghost doctor first extracted some elemental sulfur powder from the collected sulfide, which is the main component of sulfur.

Because there were no weighing tools, the ghost doctor could only rely on his senses to take an appropriate amount of sulfur, potassium nitrate and charcoal powder in proportion, pour it into a stone bowl, and slowly stir it with a thin wooden stick.

There can't be a little spark in making black powder, otherwise there will be an explosion, Ye Xiao and they won't joke with life, so there are no torches for lighting in this cave, and natural light is used for lighting.

Therefore, Ye Xiao and the others could only come here to make gunpowder during the day when the light was good.

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(Ask for recommendations, ask for comments, I always feel like it's in a stand-alone π_π)