Tan Xiaoda and Zhao Yan hurriedly asked how to obtain a stable source of saltpeter, and Liu Yan said with a smile: "Isn't it just that the supply of saltpeter is limited, so why bother?" If you want me to say, in fact, saltpeter is everywhere, such as stables, earth barns, there is a lot of saltpeter, and even in the latrines. ”

This time it was Tan Xiaoda and Zhao Yan's turn to be dumbfounded, saltpeter, which is scarce in quantity and difficult to mine, is it so common, so why can't I see it on weekdays, is there really saltpeter in the stables, earthen barns and latrines?

Liu Yan saw that the two didn't believe it, so he waved his hand and said, "Let's go, I'll take you to have a look." ”

Tan Xiaoda and Zhao Yan followed behind Liu Yan, and the three of them spent an hour almost drilling through the latrines, stables, pig and cattle pens, and courtyard corners inside and outside Dapan Fort.

After Liu Yan, Tan Xiaoda, and Zhao Yan looked around, Liu Yan beckoned two dun soldiers to accompany him, and also took brooms, dustpans, bamboo baskets and other things.

Then everyone drilled in and out of the stables and cattle pens, and Liu Yan commanded two dun soldiers to take brooms and dustpans, and swept them when they saw white mangs, and collected them all and put them in bamboo baskets.

These swept out white mangs are all nitrate, and the two dun soldiers swept more than a dozen catties in a while.

Liu Yan also stood in the shade of the latrine from time to time for contemplation, and endured the unpleasant smell to carefully observe the surface soil, and then nodded and said: "It is indeed good nitrate!" ”

Then Liu Yan frowned and hurriedly came out, beckoning the two dun soldiers to take a hoe and dig up the large piece of soil. Later, the group went to several latrines and dug up a lot of dirt in the same way.

At the same time, Liu Yan was a little unsure whether it was nitrate or not, he took some charcoal and burned it red, and then put the uncertain soil on it, and when he saw some sparks bursting out, he determined it and beckoned the dun army to take it away.

After Liu Yan took everyone to get busy, he quickly dug a lot of nitrate, afraid that there were dozens of catties, Tan Xiaoda, Zhao Yan and others followed Liu Yan to dig the soil, while listening to Liu Yan's explanation, only then did they know that these soils are nitrate, which is a material that can be used to refine saltpeter.

At this time, Tan Xiaoda, Zhao Yan and others all looked at those bamboo baskets in disbelief, and it was difficult for everyone to imagine that these latrines, cattle pens and other places would be associated with gunpowder.

Liu Yan has seen some information before, collecting some human and animal urine and feces can make nitrate, and Liu Yan is relatively clear about how to make it, but he has not had the opportunity to operate it on the spot.

A few people returned to the General Flag Hall with these nitrate soils and gathered all the nitrate together, at this time Zhao Yan asked eagerly: "Captain A, this is okay?" ”

Liu Yan said: "Of course not, these nitrates still need to be treated slightly." ”

Then Liu Yan arranged for manpower, took some plant ash, crushed the nitrate and wood ash respectively, and sifted all of them into a fine powder, filtering out all impurities.

Then Liu Yan commanded two dun soldiers to mix the filtered nitrate, grass and wood ash into a large pot according to the ratio of eight to one, and began to wash it with hot water of about 75 degrees. Of course, there is no thermometer at this time, but you can roughly determine the temperature based on the smoke of the hot water.

After uninterrupted stirring, about a moment or so, the suction filtration is carried out. Put the slag in the cauldron again, add an appropriate amount of hot water and stir for about a moment, continue to suction filtration, and mix the filtrate obtained twice together, which is nitrate.

In the next step, the nitrate water is poured into a large flat pot and heated and evaporated, this step is called boiling nitrate, and it is necessary to stir constantly when heating to prevent sticking to the bottom and splashing. When the nitrate water evaporates two-thirds of the way out, stop heating, at this time the nitrate water will become more viscous, a small amount of solid crystals should have been precipitated in the pan, and the color will gradually fade from reddish brown to white, and finally turn white, pure saltpeter crystals will be made.

Liu Yan commanded the two dun soldiers to operate on the spot, and explained to Tan Xiaoda and Zhao Yan, at this time Tan Xiaoda and Zhao Yan had already opened their mouths wide, they didn't expect that they could make saltpeter without saltpeter mines, which was something that the two of them couldn't imagine and didn't dare to imagine before.

"After that, as long as these saltpeters are crushed and stirred in proportion to sulfur, charcoal and other substances, and then put into the stone mill to grind finely, the black powder powder is born, which is made by any craftsman in Dapanbao, and the two of you are experts, so I won't say more."

At this time, the two dun soldiers also completed the production under the command of Liu Yan, and dozens of catties of nitrate finally produced less than four catties of saltpeter crystals, which is already very good, and the output has exceeded Liu Yan's expectations.

Tan Xiaoda and Zhao Yan looked at the results in front of them, and they were overjoyed in their hearts, the problem of gunpowder raw materials was finally solved, and they could be self-sufficient in the future and would not be controlled by others.

In the words of later generations, Zhao Yan is a technical nerd, very obsessed with the production of gunpowder and firearms, I saw that at this time Zhao Yan looked intoxicated, and said to Liu Yan: "The method of the first chief is really miraculous, and it is not impossible to produce 100 catties of saltpeter in a month." ”

Liu Yan said with a smile: "Now the manufacture of gunpowder is just a lack of saltpeter, and you can buy a lot of sulfur, after all, sulfur is also a common medicinal material, we can buy it for a variety of reasons, don't worry about it for the time being." Now that the problem of saltpeter has been solved, there is no longer a bottleneck in the production of gunpowder. ”

Tan Xiaoda and Zhao Yan inevitably praised Liu Yan again, and then Liu Yan said: "Actually, I have another way, which can make a large number of nitrate clay and make saltpeter crystals, but it requires a lot of manual materials." ”

Tan Xiaoda and Zhao Yan inquired one after another, and Liu Yan took the two to a remote place in the fort, where there were not many military households and civilians, and there were no buildings, it was a vacant land that had not yet been used, and there were many trees around, and this side was also a shady place.

When the three of them came here, Liu Yan ordered Zhao Yan to choose twenty women and old and weak men as Zhao Yan's daily subordinates.

Half an hour later, Zhao Yan gathered twenty subordinates and all of them gathered here.

Liu Yan immediately assigned tasks to everyone, and asked everyone to go to various latrines and livestock pens in the fort separately to collect as much human and animal feces as possible, and then mix them with sand particles, furnace ash, etc., and piled up several tall dung heaps here.

Liu Yan also said to Zhao Yan: "From today onwards, I will have to pee here regularly and at a fixed point every day. As for how to collect urine, that's up to you. ”

Soon this stinky place of nitrate collection attracted many onlookers, and everyone pointed at the few unpleasant-smelling dung heaps, whispering, Liu Yan explained the importance of this place to everyone, so that everyone in the fort must support Zhao Yan's work, and whoever passes by the surrounding area on weekdays can come over and urinate on a few dung heaps.

Under Liu Yan's orders and the efforts of Zhao Yan and others, only a few days later, a lot of white natural nitrate appeared on the surface of these dung heaps.

When Liu Yan heard the news, he immediately brought Tan Xiaoda and Zhao Yan over, and after the three of them observed it, they didn't care about the bad smell, and they all had smiles on their faces.

After estimating, Zhao Yan said excitedly: "A Chang is really a genius, there is still this way in the world to collect natural nitrate!" The subordinates estimated that at this nitrate collection site, 200 to 300 catties of pure saltpeter crystals could be easily obtained in a month, which was much easier than the nitrate mud dug from the latrine stables and other places. ”

Liu Yan also nodded, the output of this method to obtain saltpeter crystals also exceeded his expectations, and it was indeed much better than collecting them everywhere.

Two hundred catties of pure saltpeter crystallization can be made into at least three hundred catties of black powder in a month, with this lot of gunpowder, Liu Yan's series of plans can be carried out in a small way, for example, when the army is expanded soon, there is no need to worry about the ammunition of the bird's gunner; In addition, if you want to open a mine by yourself in the future, you can also use a sufficient amount of gunpowder to open a mine, and wait.

In fact, this method of collecting nitrate is also Liu Yan's reference, Liu Yan once read a relevant historical material, which records the Gaoqing County Chronicles of Linzi, Shandong: In 1944, in a certain place in Gaoyuan in Gaoqing County, there were more than 1,000 people who used the soil method to boil nitrate, with an annual output of 150 tons of nitrate, which is enough to configure 200 tons of black powder!

1,000 people made 200 tons of black powder, that's 400,000 catties!

With this local method, Liu Yan can be sure that in his military career in the Ming Dynasty, he will not worry about the raw materials for the manufacture of gunpowder. It's just that it requires a lot of human and animal manure.

In the past, the urine and feces of people and animals in Dapanbao were used to fertilize the fields, and now there is an additional function, that is, to collect nitrate and use it for battlefield tearing and killing, and to protect the family and defend the country.

Now that I see this feces and urine, they are really valuable strategic materials.

Liu Yan couldn't help laughing when he thought of this, but laughing and laughing, Liu Yan still gave an order specifically for this, in the future, the military households of Dapanbao are not allowed to defecate anywhere, they must go to the designated thatched house, and they can't be greedy for temporary convenience, in addition to keeping everyone clean and tidy, this is a major event related to the development of Dapanbao's military strength, and it is not allowed to be sloppy.

A few days later, it was sunny and sunny again.

That morning, Zhao Yan commanded the twenty men and women to pick urine and dung and go to irrigate the place where his treasure was collecting salt.

Yesterday, nearly 100 catties of nitrate have been collected from this place, and all of them have been transported to the Firearms Supervision Office to make saltpeter crystals, and the amount is also considerable. Because of the high yield, in order to collect new nitrate, this irrigation and urine must not be relaxed. Zhao Yan is also very concerned about this, and personally brings people over to "take care" of a few dung heaps almost every day.

This place is not very far from the Dapanbao New Fort Wall, just under a slope, the sun is not enough, the most shady but the best for collecting nitrate.

After regular and fixed urine irrigation every day, this place of nitrate collection can be said to be stinking far away, sometimes a gust of majestic wind blows, and the stench even drifts far away to the labor site where everyone builds the fort wall, so that many people are scolding.

Entering that place, many people can't stand it, but Zhao Yan's expression remains the same, it seems that in this stinky place, he can find endless fun, maybe this is the state of being addicted to gunpowder technology.

When Zhao Yan commanded a group of men and women to pick urine and pass through the construction site, many people greeted him from afar: "Chief Officer Zhao, go to see your precious place again?" ”

As soon as the words ended, everyone burst into laughter, as if they had found pleasure in the boring and hard work.

These days, Zhao Yan's reputation can be said to be well-known in the castle, and many people laugh when they talk about it. Many people also rumored that in order to accumulate nitrate, Zhao Yan must wear a broom and dustpan with him, and he is wandering around the toilet and stable all day long, and when he sees white blocks. will instinctively sweep up.

After listening to everyone's teasing, Zhao Yan was not angry, and said with a smile: "Yes, that is a treasure land, a treasure land that can give birth to treasures!" ”

The crowd laughed even more.