Squeezed out of the crowd, when Wu Xiu heard that he was admitted to the first place "Xie Yuan", he was even more happy.

The three of them rushed back to Wujia Village, and Feng Niang was very excited when she heard that he had won the first place in the exam. In the evening, the whole family had a good celebration.

The next day (nine o'clock in the morning), Wu Zhi was reading a book in the small study, and Jin Lian came to look for him with the little maid and the servants, and he hurriedly put down the book and went out to meet them.

Jin Lian also looked very happy. She is wearing a short-sleeved light green gauze skirt today, with a silver hairpin on her head, which looks particularly radiant.

In the past year or so, she has grown taller again, and she is only half a head behind Wu Zhi when she stands side by side, and she should be about one meter six or eight.

Seeing Jin Lian coming, Feng Niang was even happier, she also liked Jin Lian very much, and she had long regarded Jin Lian as Wu Zhi's daughter-in-law in her heart.

Jin Lian's eldest brother Pan Wei went back to Jinzhuang yesterday to report the good news to Mr. Pan, and when he said that Wu Zhi had won the first place in the exam, Mr. Pan smiled from ear to ear, and she was also very excited. So I rushed over today and said hello to Wu Zhi.

Although passing the examination is only qualified to participate in the provincial examination, it is still far from Jinshi and the first, but this qualification is not so easy to get, and the admission probability of Enzhou is only one out of twenty! And Wu Zhi is only eighteen years old now, and there are still many opportunities to pass the provincial examination and the first rank, and the future is promising!

Wu Zhi thanked her, and then took her around the village, talking and chatting with her.

Wujiana Village has a beautiful environment, quiet and comfortable, Wu Zhi likes it, and she likes it too, especially to be able to stay with Wu Zhi, she is even happier in her heart. She found that Wu Zhi has become more generous and energetic now, not only sunny and cheerful, but also easy-going and considerate, polite, witty in words, and has an indescribable charm.

Now every time she faces Wu Zhi, Jin Lian always has a feeling that her heart is hitting a deer, and the girl is pregnant. Wu Zhi is mentally mature and obviously knows her mind very well, so he cherishes the time he spends with her and tries to make her happy.

The good times passed quickly, and after Jin Lian and his party reluctantly left, Wu Zhi regained his mood and returned to the small study to remember things.

The first place in the exam, he already has the qualifications to participate in the provincial exam, and he must rush to the Beijing Division to report before the end of the year, so he can only set off in advance. It's the end of August, and time is running out for him. What should be prepared should be prepared first, and the rest should be done step by step. At that time, the provincial examination was presided over by the Ministry of Rites, and the tribute students who passed the national examination had to go to the capital to take the examination.

At the time, although the quiet and peaceful village of Samurai looked like a paradise, it was very unpeaceful outside, with bandits rampant and trouble.

Wu Zhi remembered that in September of the third year of Shaosheng (that is, the seventh year of the Western Xia Dynasty), Li Qianshun, the lord of the Western Xia, and the Empress Dowager Xiaoliang were unsuccessful in demarcating the border with the Song Dynasty, and gathered 500,000 Xia troops to attack the Song Dynasty's Dunyan Road, and trapped several villages, and the imperial court would fight with the Western Xia near Hengshan on the Dunyan Road, and it would be fought for a long time. During the period, the bandits took advantage of the chaos to break out, Hebei East Road is close to Yanyan Road, Hebei is not very peaceful, there are often bandits in the mountain water village, seeking money and killing people.

This time he went to Bianliang, Tokyo to take the exam, the road is long, and safety along the way is a big problem, so he must take precautions and do a good job of preventing risks along the way.

First of all, you must have a sharp weapon for self-defense, such as a dagger, etc., which can be hidden on the body, and this can be bought in the county seat of Qinghe County. The second is to get gunpowder and make some weapons for self-defense.

At that time, the gunpowder was all old gunpowder, composed of saltpeter, sulfur, and charcoal, which could be used but had little power. Most of the time, people just use it to make fireworks, watch the sparks and listen to them, and not many of them are used to kill enemies on the battlefield. Although the Song Dynasty already had firearms that used gunpowder at that time, such as thunderbolts, firearms, rockets, etc., the lethality was too small, and sometimes even the enemy's armor could not be pierced, and the enemy could not be injured by the explosion.

The new gunpowder that Wu Zhi wants to make is very different from this old gunpowder.

With his memories before his death, Wu Zhi knew that the saltpeter in the old gunpowder could be replaced with high-purity potassium nitrate, and after being mixed with sulfur and charcoal, the explosion power would be much greater, and the higher the purity of potassium nitrate, the greater the explosion power, and if the gunpowder was made into granules, the explosion power would be even higher.

And pure potassium nitrate can be extracted from saltpeter, as for how to refine it, he remembers it clearly, this is not difficult for him.

Wu Zhi wants to use the new gunpowder to make grenades or grenades for self-defense!

Hebei is rich in saltpeter, which can be learned from ancient books.

There is a clear record in "Tiangong Kaiwu": all nitrate, Huayi is born, and China specializes in the northwest. If the southeast traffickers do not give official citations, they will be guilty of believing that they are private goods. Nitrate is the same as salt, and it is vaporized by moisture under the earth, and it is now on the ground. Those who are close to the water and the soil is thin become salt, and those who are close to the mountains and the soil is thick become nitrate. It dissolves when it enters the water, so it is called "nitrate". Long, Huai north, the Mid-Autumn Festival, that is, in the living room, sweeping the floor every other day, you can take a little for refining.

The "Compendium of Materia Medica" also mentions: saltpeter, all brine land is produced, and Hebei Qingyang counties and Shuzhong are especially more. In autumn and winter, it is white everywhere, and it is made by sweeping and decoction. The goods are unclean, and they must be decocted in water, poured into a pour, and formed overnight. Cheng is below, like simple nitrate, also known as raw nitrate, which is said to be the nitrate that has been refined and born. The knot on the top, or there is a sharp edge such as miscanthus nitrate, or there is a ridge such as horse tooth nitrate, so saltpeter also has the name of miscanthus nitrate, tooth nitrate, and the same name as the mango and tooth of Pu nitrate, and the nature of water and fire is different. Therefore, Wu Zhi does not have to worry about the lack of raw materials, and it is available anywhere.

Just do it. Saltpeter is generally found in toilets, houses, cattle pens, old walls of courtyards, cliff sides, caves, and ground that is not easily washed by rainwater. Wu Zhi scraped a large pile of nitrate from the old wall of the courtyard and the corner of the bullpen house, and pulled out a large pile of grass and wood ash from the kitchen, and ran to the utility room to drum it up.

He first crushed the nitrate soil and plant ash respectively, grinded it finely and sifted, mixed the nitrate soil and plant ash into the ceramic tank according to the volume of three to one (the weight ratio was about seven to one), and then poured hot water of about 75 degrees (the water can be cooled for about five minutes after boiling) until the mixture was immersed, and the wooden stick was constantly stirred for about a quarter of an hour, filtered with a cloth, and the filtrate obtained was set aside; Transfer the filter residue to the ceramic tank again, continue to add hot water of about 75 degrees and immerse it in stirring for about a quarter of an hour, and filter it with a cloth again. Pour the liquid filtered twice into a large iron pot, slowly heat and boil nitrate, and stir continuously with a wooden stick when heating to prevent bottoming and splashing. When the liquid has evaporated three-quarters of its volume and a small amount of solids are precipitated in the pot, the heating is stopped, and the cloth is filtered while it is hot, and the crystals left on the filter cloth at this time are sodium chloride. Put on a new filter cloth, and when the filtrate cools down to about 30 degrees (when it is not hot, not hot, and not cool to the touch), he sees a large number of crystals precipitated out, he filters it again, and as the liquid is filtered out, the crystalline solid left on the filter cloth is potassium nitrate! The filtrate is recovered and then used to soak a mixture of nitrate and plant ash. Pour the crystallized potassium nitrate solid into a large iron pot and immerse it in hot water again, stir to completely dissolve it, stop heating when heating and concentrate until the solution is white and bright, filter and transfer to a large vat, cool the crystal, and filter the crystals obtained again is high-purity potassium nitrate. Filtrate recovery can also be reused.

The first time he operated, he was busy sweating profusely.

When he finally saw the crystals on the filter cloth, Wu Zhi knew that he had really refined the high-purity potassium nitrate, and he was excited. He did it a few more times, and each time it was successful.

Finally, looking at the small pile of sparkling potassium nitrate in front of him, about four or five catties, Wu Zhi's eyes lit up, and he was relieved.

Xiao'e was in a hurry to help him from beginning to end, she didn't understand what Brother Da Lang was doing, and when she asked, Wu Zhi only said that it was useful. Although she was confused, she still followed him with great interest, and when she saw Wu Zhi get a crystal from the "water" (she thought it was water) like a trick, her eyes were so surprised that her eyes were about to pop out: Brother Da Lang is really amazing!

After drying the potassium nitrate and grinding it into powder, Wu Zhi made a special trip to the county seat of Qinghe County, bought enough sulfur and charcoal from the grocery store, and also found some fir wood chip powder. At the same time, he also bought a delicate dagger and a holster, tried it, it was very sharp and very handy, but it also cost him a piece or two of silver, and good things are expensive.

When he returned home, Wu Zhi also fried nitrate, that is, potassium nitrate was fried with sawdust powder. The method is to make a simple stove, put a big iron pot on the shelf, burn firewood at the bottom, the fire can not be too big, add an appropriate amount of sawdust powder to make leavening agent, you need to fry slowly and carefully, you need to pay attention when frying, do not touch the open flame, otherwise it is easy to catch fire and explode. Stir-fried over low heat, after drying, can reduce the moisture in potassium nitrate, can increase the storage time and increase the explosion intensity.

After frying nitrate, Wu Zhi crushed the sulfur and charcoal respectively, first calculated the amount on paper according to the ratio of 75 percent potassium nitrate, 10 percent sulfur, and 15 percent charcoal, because some fir powder was added to the potassium nitrate when frying nitrate, so Wu Zhi appropriately reduced the amount of charcoal (that is, the amount of fir powder) when calculating, weighed a small pinch with a scale, and then mixed them together, put them on a piece of paper, rolled them into a ball, found an open place to put it, lit it and tried it, It was found that the deflagration effect was not bad, better than the old gunpowder at that time.

After countless tests, Wu Zhi finally found the best combination ratio of the new gunpowder deflagration effect, that is, 74.5 percent potassium nitrate, 12 percent sulfur, and about 13.5 percent charcoal and fir powder. And he also found that adding a little more sulfur made the gunpowder deflagrate more powerful. The better the deflagration effect, the stronger the explosion effect of the bomb made from it.

Wu Zhi recorded the ratio of potassium nitrate and fir powder when frying nitrate, and the best ratio of potassium nitrate, sulfur, and charcoal in the new gunpowder in the notebook for future reference.

Striking while the iron was hot, Wu Zhi mixed the remaining potassium nitrate (fried potassium nitrate), sulfur, and charcoal according to the optimal ratio obtained from the test, stirred it evenly with a wooden stick, put it in a dry jar, sealed the mouth of the jar, and hid it in a safe place for preservation.

This new type of gunpowder is an extremely dangerous thing, it must not be placed indiscriminately, it must be properly stored, it must be kept away from the fire source, and fireworks are strictly prohibited!

After careful consideration, Wu Zhi decided to make some of the powdered new gunpowder into granular new gunpowder, and see if the explosion effect of the granular new gunpowder was better than that of the powdered new gunpowder explosion.

In one go, Wu Zhi found some alcoholic wine, took out half of the new gunpowder in the jar, poured some alcoholic wine into a paste that could be kneaded into a ball in his hand, and then found a fine-hole bamboo sieve, spread the gunpowder paste on the bamboo sieve, and wet milled it with a wooden stick, and the small gunpowder particles naturally fell from the sieve hole to the receiving plate, and after the gunpowder particles dried, Wu Zhi put them into another dry jar, sealed the mouth of the can, placed them in a safe and cool place, and stored well.

And just like that, the new gunpowder was finally made!

All that remains is the question of how to use the new gunpowder, and Wu Zhi has long been aware of this.