Let's say that Dean Ma got such a clever plan to make money, so he happily returned to the academy, and then rolled up his sleeves and prepared to do a great job.

The blackboard is easy to say, just find a carpenter hoop and put a few flat planks on the bracket obliquely, and then paint it with black paint, so as to ensure that the county lord is satisfied.

It's that this chalk is a little troublesome to make, Ah Yuan was fortunate to have worked in Sixia in his previous life, and he also drank white ash in a simple chalk factory, so he can know an approximate ratio.

The main raw materials for making chalk are calcium carbonate and burnt gypsum, and it is said that the reason why chalk is easy to break is that it is simply made by burning gypsum and adding water, without adding calcium carbonate.

It's a pity that Ah Yuan is a half bottle of vinegar, the chalk factory is a ready-made purchase of raw materials, only need to prepare according to four parts of calcium carbonate, eight parts of burning gypsum, and ten parts of water, the preparation method is to mix calcium carbonate and burning gypsum first, add water and mix evenly to make a thin slurry, and then quickly pour into the holes of the metal model pre-coated with oil, about ten minutes or half an hour after all solidifying, you can disassemble the model, take out and dry it.

Coming to the Great Song Dynasty, I really don't know how to extract calcium carbonate, Ah Yuan, can only talk about the principle of burning gypsum, burning gypsum is cooked gypsum, is to fry gypsum powder in an iron pot, when the temperature reaches 210-220 degrees, gypsum powder will be like water waves, indicating that it has been fried.

At this time, mix the plaster and limestone powder according to 6:4, and then mix it with the same amount of water into the mold, and it can be dried in about 6 minutes. However, when entering the mold, it should be noted that each piece of chalk should be enriched without bubbles, if you want to improve the quality of the chalk, the fried gypsum can also be sieved before use, such as after the water should be immediately put into the mold. so as not to solidify and be invalid.

Dean Ma is also half-understood. Fortunately, there are many masters in the academy who are willing to use their brains to think about things. Hearing the dean's incitement, he immediately prepared lime powder gypsum, asked someone to make a mold, and hurried to experiment.

"You say, why didn't we think of it? If you write the content of the lecture on the blackboard at any time and teach the students, it is much better than sitting there and just preaching. ”

Dean Ma shook his head and sighed at his master, and made up his mind that as long as it was feasible after the test, he would immediately nail a blackboard to every teaching house, and it didn't matter if the blackboard eraser could not be made. You can use the rag first, and use it over and over again.

The reason why I gave up making a blackboard eraser is because when I heard what the county lord explained, it was necessary to tie it up with short, hard pig hair and stuff it into a wooden board full of small round holes, so how could it be fixed? The master in the academy is not good to go to class with his hands full of loose pig hair......

In fact, it is a pity that he gave up, many things are very difficult to think about, but it is relatively easy to do, the brush used by readers. Isn't it just a way to tie up the hair and stuff it into the pen holder? If you do it right, it won't fall out easily.

Lord Fury had no choice but to keep such a "difficult" deal to himself. When sketching the drawings, I also added the prototype of the toothbrush and handed it to Zhang Dashan to lay it out.

It's really embarrassing for Ah Yuan, who has lived for two lifetimes, to come to the Great Song Dynasty for many years, and still maintain the original record of rinsing and brushing his teeth with a wicker stick dipped in green salt, if it weren't for Dean Ma's refusal to develop a blackboard eraser, the heartless county lord would not be too lazy to innovate!

However, the black pig hair and bristles are hard to make a toothbrush, right? Zhang Dashan also knew that he had to find a substitute as much as possible, at least white and bright, a little more beautiful, and hard enough and fine......

Later, Zhang Dashan, who has adapted to being a part-time housekeeper for the county lord, got inspiration from the toothbrush and blackboard eraser, and created a shoe brush with a shape close to a toothbrush and a volume similar to a blackboard polish, which suddenly won the admiration and welcome of the people of Yifu, because this shoe brush is really easy to use.

Like now, it is easy to use a shoe brush to rummage in the cloth shoes and roll around the cleaning.

Naturally, the county lord's mansion made a steady profit, and there was another processing plant in Zhuyang County, and the products sold well all over the Great Song Dynasty.

Five days later, Zhuyang County's "Xin Xin Academy" ushered in the first unique "County Master Lecture".

After five days of preparation, the chalk production of "Xin Xin Academy" was finally barely qualified, and the blackboards were not old and young, standing in a long row on the ground.

But why are there so many people? In addition to the academy's own masters and students, how can there be countless onlookers among the teachers and student representatives of other schools who are invited? Their faces were full of eagerness, and they refused to go out with the sticks on the top door......

It's as if a big-name movie star in his previous life was going to participate in an event, and there was a sea of people on the inside and three layers outside, which was not an ordinary spectacular, it was quite spectacular!

The protagonist of the "spectacular", Lord Fury, was moved at once.

Pingsheng - no! I've never received such a warm welcome in my life! The little heart really can't stand it, "poof, poof" is beating wildly, and I can't wait to jump out of it hotly......

Dean Ma and Hu Xianling led the way in front of them, and on the left and right and behind them were their own majestic "guard brothers", at this moment, they were all red and tight, and their chests were tight, while protecting the county lord from being hit too warmly, while proudly raising their chins with honor.

Later, it is Zhanzhao Zhan's guard, and Zhang Dashan has three followers before and after, Song Hao didn't do a "fart bug", she was fascinated by a few shiny gems, it is said that she wants to stay at home to draw a sketch of a hairpin, and she must be beautiful before stopping.

"Evil Star" also carried a large aluminum horn in his right hand, this thing looked strange, and it was so big that the young man was a little embarrassed to hold it.

Ah Yuan was too addicted to stardom, waved her hand and smiled, if it weren't for the fact that she still had a string in her head that was in another world, she would almost reach out to send a "flying kiss......

"Next time there is such an event, well--we have to let them prepare for the red carpet in advance, so that they can step on it to be ......more stylish", no one knows, what kind of mess is going on in the mind of Lord Fury, who is smiling like a flower!

What she prepared today is a "line" with vermilion as the main tone, simple cutting and sewing, set off with the same color of flower and grass embroidery, which will not dazzle the eyes of flower people, but can tell a kind of low-key luxury.

The head was still freshly combed in a bun, a silver hairpin inlaid with precious stones, a fine silver chain hanging from the branches, and three tiny, colorless gemstone stars, occasionally flowing with the refraction of the sun.

The light makeup I painted, there is no hiding at all, the skills of makeup in the beauty salon in the previous life are all dedicated to a face, how the expression only reveals the word "beauty", especially when laughing, the eyebrows and eyes are turned and looking forward to it, which can be described as thrilling.

"The county lord - the county lord! ——", the cries came and went.

The overly beautiful county lord finally broke through the encirclement and walked to the table that had been packed up in advance, and Dean Ma and Hu Xianling sat on both sides, which further highlighted the beauty and dignity of a little red flower in the green bushes.

Ah Yuan didn't sit down, but reached out to take the loudspeaker from the hand of the "evil star", held it to his chest and said: "Thank you for coming to listen to my lecture ......."

This horn is still a rarity, and it hasn't been spread in the capital yet, and the loud noise has scared many people.

"The county lord's voice is really high!"

"What kind of monster is this? Covering most of the county lord's face, he can't see anything! ”

The crowd is a little chaotic, which is normal, and big names with star fans have to be like this.

Ah Yuan's voice hovered in the middle of the academy: "Please sit down on the spot with the students who are close, so that friends later can also see and hear ......."

No one specially presided over discipline, the county lord called for such a call, and it was really "uproar", and sat down in a large area, quite well-behaved, the students were in front regardless of whether they were young, the masters sat behind the students, and the uninvited audience automatically and consciously stood at the back to listen.

So many people gathered here, and it was quiet for a moment, and a pair of bright and clear eyes looked at Ah Yuan, all the way into the depths of her heart.

"Today, I'd like to start with the perimeter of a few figures, extending to the concept of area. This was not a course I prepared in advance, but, on the way here, I saw a lot of puddles and ditches, and the small river was full of rainwater, this autumn, the rain was too kind to us in Zhuyang County, even if we already felt that the rain was enough, too luxurious, God still continued to give, I want to ask, who knows, what should we do? ”

The crowd erupted in laughter, as they thought the county lord's tone was very coke. As for what to do as a human being in the event of a natural disaster? So what else can I do?

"County Lord, God doesn't listen to us, if the rain continues and floods the home, we have to escape the famine, wait for the rain to go down, and then come back!" This is the farmer standing in the back row shouted, although he has never been to the school, he is also interested in the problem of "the administrator releases water", and heard that the "Xinxin Academy" has a lecture by the county lord, and he also came to audit.

"What you say makes sense, but with so many of us and so many smart brains, can't we think of a way to fight against God? The drought is drought, we know to go to the river to water the ground to solve it, this heavy rain continues, we can definitely solve it, right? ”

Ah Yuan no longer waited for the answer she was hoping for, the Great Song Dynasty had a lot of experience in fighting disasters, but there was no precedent for digging reservoirs to store water, and she felt that she had an obligation to let this simple method come to life at this moment.

"We are always in the spring drought, chanting the allusion that 'spring rain is as precious as oil', so why not dig a large-capacity reservoir in the rainy season to save the rainwater and wait for the spring next year to solve the drought? The lesson on the perimeter and area that I am going to talk about today is to prepare for what kind of reservoir we want to dig in Zhuyang County later, how big the reservoir will be, and how ...... we will prepare." (To be continued......)

PS: Thank you Snow Song 1972 and soi for the pink ticket, thank you for the aadg tip!

Recommend a friend's book: "The Fierce Wife of the Farmer" Author: Wan Lan

Introduction: Brave through the female for the sake of harmony, see how she kicks the scumbag, fights the best, leads her son to be well-off, and harvests her happiness with her hands...