In the 19th century, black lacquer was applied to the surface of wooden boards to protect them from erosion, and later some people found it very convenient to write and draw on them, so by the mid-19th century, blackboards became popular in Western schools. It is said that the first blackboard used for teaching in China appeared in 1862 at the Kyoshi Tongbunkan, and a large number of teaching blackboards in Fuso appeared after the Meiji Restoration.

The chalk used by Naohide is made by pouring raw gypsum into a thin bamboo tube and adding water to solidify.

In addition to introducing himself, Naohide also drew a map of the world on the blackboard in advance, the scale was not accurate, and the graphics of the continents were not accurate, and only a few countries were indicated on it.

"Welcome everyone, today we will exchange some knowledge together, the fool is still learning, it is inevitable to laugh and be generous, please don't hesitate to teach", bowing slightly, Naoxiu began his first lecture.

Naoxiu started with Lanxue, "Lanxue refers to the knowledge that comes from Languo, in fact, Lanxue is not only the knowledge of Languo, but the knowledge of the entire Europa continent. So where is Europa? ……”

Naohide first introduced the world map on the blackboard, and also admitted that the map was not accurate, and then a simple geographical introduction. "The earth is round", many of the Lan scholars in Fuso now accept the concept that the earth under their feet is a sphere, and some people have seen a globe.

The world's first globe was invented in 1492 by the German navigator and geographer Beheim and is preserved in the Nuremberg Museum. During the Azuchi-Momoyama period, missionaries dedicated a rudimentary celestial globe (globe) to Oda Nobunaga, a daimyo of the time.

Because there are no observation tools such as satellites, and the current measurement methods are very crude, there are many errors and omissions in the current maps and globes.

The public presentation of the map is not too much in line with the regulations of the shogunate, but fortunately, Naohide's map is quite rough, so let's talk about it when the shogunate is really going to be held accountable. But without talking about the world map, Naohide always felt uncomfortable.

Naohide first explained some of the evidence in Ranology that "the earth is round", and the horizon is arc-shaped; When a ship comes from afar, it always sees the mast first, then the hull; During a lunar or solar eclipse, there is always a certain arc to observe the shadow surface of the Moon or Sun; On the circumnavigation of the world, Naoxiu also casually rowed a round-the-world route from Fuso around South America, North America, Europe, Africa, India, the Strait of Malacca, Luzon, Ryukyu, and Fuso.

Another evidence is that during a partial lunar eclipse, sunlight casts the Earth's shadow on the moon's surface, giving us a glimpse of part of the Earth's spherical shape.

Speaking of which, Naohide invites everyone to ask questions. The current style of education at Kodokan is relatively strict, but later in 1855, due to the dissatisfaction of Shigenobu Okuma and others with the reform of the solidified education method, it also caused a riot in Kodokan, so there was a cold scene after Naohide asked.

Naohide didn't expect to get an enthusiastic response at the beginning of the lecture, and he was afraid of asking some embarrassing questions, so he quickly wiped the map off with a cotton bag, and since then he has no proof, and he will not admit that he drew this map in the future.

In fact, Kodokan does not take the initiative to ask Naohide to give a lecture, and Naohide will also try his best to give a lecture - it is very taboo to visit the feudal priests in Saga Domain for no reason, so lecturing is the best way for Naohide to contact the feudal priests, and Naohide has also made careful preparations for this.

Naohide waved his hand domineeringly, Toranosuke and Gakujiro had already heard what Naohide said, so they were a little distracted, "Windmill-", the two hurriedly took out the toy windmill and sent it to everyone.

The windmill is beautifully made of colored paper, because of the large number of people, the air is not good, and the light is not good, Naohide is open to give a lecture, and the windmill turns very beautifully, but the audience is at a loss, "Naohide of Edo, stupid of Edo, right?" Aren't we here to listen to Lan Xue? Where am I? ”

At this time, several servants and a carpenter placed a wooden model more than one person tall on the floor of the doorway. Zhixiu is also fighting, the first day to make the drum when I booked this model, before and after I don't know how many craftsmen rushed to finish, this is because they have experience in making pedal waterwheels, a total of 15 Tianbao small judgment was spent on Zhixiu, but it's really worth it.

In 1854, the mechanic Daniel Haraday invented a pumping windmill, and his invention proved for the first time that the windmill can control the speed while automatically changing the wind direction without the help of manpower, so the windmill will not be damaged by the storm due to too fast speed, which is a classic representative of the rice-style windmill.

Naohide copied this classic, and made this model thanks to the superb skills of the current Fuso craftsmen.

When the carpenter demonstrated that the model lifted the water from the wooden basin, the students all squeezed forward and scrambled to watch, Naohide then moved the direction of the model, and when he saw that the windmill automatically turned and lifted the water normally, "boom-", the students began to speak loudly, but when Naohide explained that he could control the speed and not be afraid of the storm, even Mr. Hyun Park squeezed over to observe it himself, and now no one cares about Naoxiu.

Because Fuso suffered from storms (typhoons and storms), people had an instinctive fear of the wind, and there were no records of large windmills until the end of the Edo period.

The earliest record of a large windmill in Fuso is an American farm in Negishi, Yokohama, in 1869. In 1888, the Freis Women's College in Yokohama used windmills to supply water, and it caused a sensation at the time, calling the college "Red Windmill College".

The first windmill developed in Fuso appeared in 1902 when Juntaro Ito, a villager from Hunan Village, Nanshin Prefecture, Nagano Prefecture, successfully used a windmill to fetch water, and the windmill had 6-8 blades, 55 cm long and 23 cm wide.

Hongdokan educates students to apply what they have learned, so students can understand the meaning of this windmill, Fuso has a large population, livestock is very scarce and precious, there is no steam engine yet, only some hydraulic machinery, the appearance of this windmill will bring great changes, students don't know how much they can change, but they still vaguely feel that what they see today is something that may be great in the future.

When everyone's mood calmed down, Naoxiu asked people to move the windmill away - if they didn't move, everyone's attention was distracted.

Naohide talked about the concept of "horsepower" and talked about the steam engine. At present, the merchant ships visited by Lan Guo are all sail ships, and everyone here has also heard some rumors of steam engines, but there is no specific concept, so Naohide carefully talked about the example of steam locomotives.

In 1825, George Stephenson, an Englishman, invented and built the steam locomotive "Voyager". At that time, the Voyager was towing 6 coal cars and 20 cars packed with passengers, carrying 90 tons and traveling at 15 miles per hour. With the chirping of a train, it announces to the world the arrival of the railway age.

In 1829, George Stephenson and R. Stephenson jointly designed and built the "Rocket" steam locomotive with a maximum speed of 47 kilometers per hour, a dead weight of 4 tons, and a traction load of 12 tons.

In order to establish an intuitive concept of the students of Kodokan, Naohide converted the unit of weight into the unit of weight of Fuso. The weight of Fuso is 37.5 kilograms. The "stone" is a unit of volume, and one stone of brown rice weighs about 110-130 kilograms.

When the students heard that the train of 18 years ago could pull nearly 700 stones, and the train of 14 years ago could run faster than a horse, and Naohide also said that it was understood that the current Europa powers are all railways running through the country, the speed of the train is faster than that of galloping horses, and the single load capacity may exceed two thousand stone ships, everyone trembled, and it was impossible to say whether it was excitement or fear, some people were questioning loudly, and some people were silently pondering.

After Naohide and the others quieted down a little, they added another fire, saying that there might be a steam engine equivalent to a hundred horses, the size of only sixteen tatami mats.

Naohide announced a temporary break and would resume later, leaving a group of students talking to each other.

Mr. Xuan Pu beckoned Naoxiu to come over, and shook his head with a wry smile before he spoke, "Inexplicably surprised, surprised." Is what Nao-suk-kun said today true? Who gave it? ”

"It's true, the details are debatable but not much different. As for whom? , please forgive me for the time being."

Mr. Xuan Pu often went in and out of the homes of high-ranking officials and dignitaries, and he was well-informed, and he had vaguely heard about the "Lanrenfeng Tales" and "Tang Renfeng Tales", and knew that the shogunate had some Western confidential information, so he just instructed Naohide to "stop here, and only introduce the specific knowledge of Lanxue later."

Listen to people's advice and eat well. After a break, Naohide stopped asking questions and talked directly about the Western scientific system.

Mathematics is the crown of science, which can clearly describe the world we live in and the laws of its operation, and it can also cultivate the spirit of rational inquiry. Naoxiu introduced the contents of elementary mathematics, variable mathematics, and modern mathematics.

Elementary mathematics includes arithmetic, geometry, and algebra, which belongs to the mathematical knowledge of primary and secondary schools in later generations. Naohide gave a few examples to explain, such as the classic problem of chickens and rabbits in the same cage, and then listed the formula on the blackboard to solve, for fear that the listeners would not understand, Naohide also deliberately explained in detail with words, and Fuso's mathematics also had an explanation of this aspect, so everyone listened to it more interestingly.

Variable mathematics includes analytic geometry, calculus, probability theory, and projective geometry, and the outstanding feature is that it realizes the combination of numbers and shapes, which can study motion. Naohide doesn't want to go deeper, but just wants everyone to have a preliminary understanding, for example, "integral science provides a set of general methods for defining and calculating area, volume, etc.", and then Naoxiu calculates the area of an irregular figure for everyone.

In terms of probability, Zhixiu gave everyone an example of copper coins, found ten students to throw them twenty times each, and then calculated the results of the positive and negative sides, and the number of positive and negative occurrences was 97:103, which was also considered to give face, that is, these children threw copper coins after they went home, which caused confusion among some parents.

Modern mathematics refers to the mathematics of the 19th century, and the mathematics of this period has three characteristics: analytical rigor, algebraic abstraction, and non-Euclidean geometry, and the representative content includes real function theory, non-Euclidean geometry and abstract algebra.

At this time, many papers in modern mathematics have not yet been published or are not widely known, and Zhixiu has also learned nine tricks more than ten tricks in his previous life - one is better, but he knows a little, so he took out a piece of paper and bent it to demonstrate the concept of non-Euclidean geometry, and looked at the mosquito coil eyes of a group of people below to know that it was in vain.

Mathematics is followed by physics and chemistry.

In physics, Naohide talked about the law of gravitation and Sir Isaac's three major mechanical equations, and explained why the earth is round and we didn't fall down.

Chemistry explained the theory of elements and chemical reactions, giving two examples: the discovery of oxygen and the "lead ash blowing silver method".

In the sixth year of Ernst & Young (1777), the French scientist Lavoisier heated mercury and found that with the formation of red mercury, the volume of air decreased by 1/5. Lavoisier then continued to heat the slag, which reduced the mercury from the slag and released a large amount of gas, which makes the candle burn more vigorously and is beneficial to the animal's breathing. Lavoisier called the gas bound to mercury a "living gas" because it was necessary for respiration; The remaining gas is called "inanimate gas" because it can extinguish the candle and suffocate the animal. Later, people changed the name of "living gas" to oxygen and the name of "inanimate gas" to nitrogen.

"Lead ash blowing silver method": silver in nature is mostly symbiotic with other non-ferrous metals, and the content of silver is often small, so it needs to be separated and purified. The ash blowing method mainly uses silver and lead inter-fusion, heating liquid lead to dissolve the silver in the ore group in the lead, and continuing to heat the lead oxide to deposit, so that the silver and lead can be separated, and the silver is purified, the specific method is:

The preliminarily processed ore is placed in a furnace and covered with charcoal about a foot thick, and when the charcoal is fired, the ore becomes an ore mass.

After the lead is melted, the ore mass is put in, lead and silver have mutual melting, and the melting point and boiling point are different, and the element activity is also different, the temperature in the furnace rises through the blower ventilation, and the lead in the ore group reacts with oxygen to form lead oxide sinking, and then cools and condenses to obtain crude silver and silver-lead alloy that can be further purified.

The silver-lead alloy is put into the furnace and continuously aerated to completely vaporize the lead to obtain purified silver.

When I heard how to make silver, everyone was in good spirits, although I couldn't use it, but what if?

Zhixiu saw that everyone was tired after listening to so much, so he talked a little about the preparation of glass, and mentioned two sentences that plant ash and lead can reduce the temperature required to refine glass-Lan scholars already have a concept of temperature, and many Lan doctors bought thermometers from Lan Guo Shangguan to diagnose the condition.

Best, Naohide explains how coke is made, and explains that coke can greatly increase the temperature of the blast furnace, helping to make iron, steel, and glass.

After a cramming, all the listeners were exhausted, only a few students still followed Naoxiu's train of thought, Naoxiu secretly remembered the appearance of these people, and then, Naohide announced the end of the lecture, and the students of Hongdaoguan bowed and thanked, and Naohide also returned the salute.

After the show, several samurai came over to introduce themselves to Naohide, leaving the address of their residence, and asked Naohide to be a guest when he had time, including Sano Eisu (Sano Tsunemin), Shimada Uemon (Shima Yoshiyu) and Sokushima Jiro (Sokushima Tanetomi) who Naohide wanted to get acquainted.

Naohide didn't expect much from the lectures, but the lectures opened up a new world for these young students, as the Fuso proverb says, "Whatever you do, it always takes years to get it done", and the subsequent development was very pleasantly surprised: 27 students from the Kodokan came to listen to the lectures, and 17 of them continued to study orchid and Western studies, forming the "Windmill Group", a mutual learning organization, and later generations collectively called them "Seventeen Masters of the Windmill Group", and this lecture was also called because of the medical hall that took place in Hachimankoji The Lecture of Hachiman Koji".