Chapter 21 Building a Sextant Study Photography

Human beings have known for a long time to navigate the sea through astronomical observations, and the ancients in China have known for a long time how to navigate ships at sea by crossing the sea, and they have reached a very high level.

Zhang Zhimu had also fiddled with the sextant before, although he didn't take it too seriously when he was playing at the time. It's not too hard to recall. If this thing is not in real condition, it will take a lot of effort to explain it to people. It's not hard to see the real thing.

After Zhang Zhimu returned to the kiln, he made a simple experimental model sextant and discussed this matter with Lu Bingyi. Lu Bingyi made a very detailed calculation for this. In the end, Lu Bingyi told Zhang Zhimu that using a sextant is a very good way to locate and navigate. However, this requires a complete system to support it, not only a sextant, but also a clock with high accuracy. Even the accuracy of the clock can largely determine the accuracy of positioning. It is also necessary to have a complete star map of the celestial coordinate system, which should be marked with the coordinates of the declination and right ascension of the main stars, and accurately describe the declination and right ascension of the sun and the moon. Based on this, an astronomical almanac was compiled. These things are Lu Bingyi's growth. At the suggestion of Mr. Zhang Zhimu, Mr. Lo Bing-yi has set up a preparatory group for the compilation of astronomical almanacs under the leadership of one of Mr. Lo Bing-yi's disciples.

With these foundations, it is much easier to determine the local latitude and longitude using a sextant.

So when he was studying the sextant the next day, Zhang Zhimu invited Lu Bingyi and Sun Liang, as well as the people who were working on the clock.

First of all, Mr. Lu Bingyi gave a lesson to everyone. Lu Bingyi introduced the concept of right ascension and declination of the celestial coordinate system, and then deduced the formula for measuring the angle of celestial bodies with a sextant and calculating the accuracy dimension. The time parameters in this formula are provided by the people who make the clock, specially made for navigation.

In fact, Zhang Zhimu quickly explained to everyone the working principle of the sextant with a model.

The principle on which the sextant is based is simple: the angle of reflection of the light is equal to the angle of incidence. In fact, a sextant can also measure the angle between any two objects.

The sextant has a handle on the back of the fan-shaped frame for holding, and the frame is equipped with a movable arm, and the uppermost end of the movable arm is the indicator mirror; The semi-reflective horizon mirror is mounted on the left side of the sextant (in the middle, facing the telescope), and there is also a filter next to the horizon mirror for measuring bright objects such as the sun. When measuring the horizon height of a celestial body, the observer holds a sextant to keep the telescope tube horizontal, and observes the image of the measured celestial body reflected by the horizon mirror from the telescope. At the same time, the movable arm should be adjusted so that the stars fall on the horizon as seen in the telescope. This is also the reason why horizon mirrors need to be made of semi-reflective glass.

When the image of a celestial body coincides with the horizon, the height of the celestial body is equal to twice the angle between the horizon mirror and the indicator mirror. Properly designing the scale on the arc scale based on this will allow the observer to read the celestial altitude directly. To improve the accuracy of readings, a drum wheel and vernier ruler are attached to the sextant movable arm.

Zhang Zhimu knows that as long as he introduces these basic things, these smart people will digest them by themselves and make the sextant more practical.

After listening to Mr. Lu Bingyi's lecture and Zhang Zhimu's introduction to the sextant, Shi Tao said: "Today, I really opened my eyes. I used to think that I had learned the ability to lead the stars and cross the sea, and I always felt that I was amazing. To be honest, what we can understand about Mr. Lu Bingyi and Mr. Zhang is that we first accept the concept that the earth is round, and we have deepened this concept through today. However, I know that there is still a lot of work to be done before these things can reach the practical stage. I would like to take a leave of absence with Commander Fan and stay in the kiln to study the issues related to the sextant with you. ”

Zhang Zhimu and Fan Chengkun both agreed that Shi Tao would stay and participate in the study of sextants and other things.

Lu Bingyi simply suggested that a maritime navigation system research and coordination committee be set up to coordinate the work of all aspects in detail, and Zhang Zhimu and Lu Bingyi personally took the lead in this matter.

Everyone unanimously agreed with Lu Bingyi's suggestion, because there were too many people and departments involved in this matter, and it would be much easier for Zhang Zhimu and Lu Bingyi to come forward. This would also reduce the burden on specific staff and allow them to concentrate on specific technical tasks.

In the end, Zhang Zhimu said: "Today's matter is decided. After a few days of visiting, you get to work. You can choose your office location in Yaogang College, where the conditions are good and the scientific research atmosphere is also good. The specific processing of the sextant is arranged by Sun Liang, and Sun Liang has experience in engaging in high-precision things. ”

Sun Liang and the others also readily agreed. The work on the astronomical calendar still needs to be staffed, and Lo Bingyi said he will think about it again.

Zhang Zhimu said to everyone: "We are in the kiln gang, there is no shortage of anything, and there is a shortage of useful talents." Everyone has to find a way to dig talents for us to come over, remember that there are rewards. ”

Everyone laughed, but they knew that Zhang Zhimu's words were not a joke.

After sending away Shi Tao and Lin Zongwei to visit, Zhang Zhimu came directly to Yaogang College to find Qingfengzi. He wanted to arrange for him to take pictures as soon as possible.

When he came to Qingfengzi's laboratory, Zhang Zhimu frowned, Qingfengzi's laboratory was still a mess, the utensils used in the experiment were everywhere, and the lunch boxes that were not brushed after eating were left next to no one to care.

Seeing Zhang Zhimu coming, Qingfengzi greeted him and asked, "Mr. Zhang, you must have something to do with me, you can tell me quickly." We're experimenting. ”

Zhang Zhimu said angrily: "I suggest that you stop all experiments. ”

Qingfengzi was stunned for a moment and asked, "Why?" ”

Zhang Zhimu said: "Let me tell you, without a rigorous work attitude, you will not be able to do scientific research work. ”

Qingfengzi was also a little excited, and asked, "Why do you say that we don't have a rigorous attitude?" Each of our experiments is carefully prepared. ”

Zhang Zhimu said: "I don't need to look at you for anything else, just look at your messy environment, which doesn't look like a place for scientific research." This shows that you are very poorly organized, and will not arrange your working environment reasonably, which reflects your impetuousness. ”

Qingfengzi originally wanted to defend himself, but when he saw that the laboratory was too chaotic, he knew that he couldn't get by. smiled and said, "Mr. Zhang, don't be angry. I'm too busy to take care of some of them, and my disciples are even lazier. ”

Zhang Zhimu said: "There will be apprentices if there is a master, and the rigorous work style is cultivated from bit by bit." If our students see that you work like this, they will learn from you and they will all be like that. ”

Qingfengzi was convinced this time and said, "It's our fault, especially mine." It's that I can't ask of them. It won't be like that in the future, I promise. ”

Zhang Zhimu relieved himself at this time, he didn't want such a high-end place to be like a pigsty. But Qingfengzi has already said this, so there is no need for him to ignore people, and said to Qingfengzi: "Let's sit down." I have a task for you. ”

After the two sat down, Zhang Zhimu said, "Now there is a business dedicated to portraits, right?" ”

"Yes, painting a picture of a person is called a small photo, and drawing a picture of a dead person is called an image."

Zhang Zhimu said: "I want to make a kind of thing that prints portraits on paper, which is called photography." ”

Zhang Zhimu knew that Qingfengzi could not understand what he said, and continued: "We poke a small hole in the window paper in a dark room, and the scene outside the window will be imaged on the wall in the house. If we block the light from the hole with a blank piece of paper, the view outside the window will be reflected on this piece of paper. ”

Qingfengzi said: "I know this. That is, the shadow that comes out is upside down. ”

Zhang Zhimu said: "Great. Wouldn't it be nice if we could fix this image? The work we have to do is really the work of fixing this image. ”

There is still no way for Qingfengzi to do this kind of thing, so he asked: "Mr. Zhang, you just said what you need to do, right?" ”

Zhang Zhimu said: "In the chemistry class I told you, there is a class of halogen elements, which we commonly use **, and we will soon use iodine and bromine. Among them, bromine is more active than iodine but weaker than chlorine. Both silver iodide and silver bromide can decompose when exposed to light. Silver bromide is much more sensitive to light than silver iodide. As long as we mix silver bromide in gelatin, apply it to the glass plate, and let the image outside the window be exposed on the glass plate for a few tenths of a second, the light will form an exposed image on the glass plate. At this time, the image is invisible to us, and it is also called a latent image. We need to use a developer to show the image, and the developer we use sodium sulfate solution. After the glass plate is placed in the sodium sulfate solution, the image will be gradually displayed. However, the generated image is not yet stable, and the residual silver bromide can continue to be exposed and developed. We also need to use a fixer to stabilize the resulting image. We mainly use sodium thiosulfate, anhydrous sulfurous acid, acetic acid, potassium vanadium, and boric acid for the fixer. ”

Qingfengzi used a pen to remember Zhang Zhimu's speech.

Zhang Zhimu continued: "This is only the first step, we just made the negative, if we want to produce a real photograph, we can coat the cardboard with silver bromide, use the negative to cover the exposure, and then develop with developer, fix with fixer." So that the photo comes out. Of course, this kind of hard paper is better coated with a layer of barium oxide and resin, such paper works better. ”

Qingfengzi sorted out the notes he took and said: "I can get sodium thiosulfate, anhydrous sulfurous acid, acetic acid, potassium vanadium, boric acid, and sodium sulfate here, but where do you get the silver bromide you said?" ”

Zhang Zhimu said: "In fact, we can use the method of burning seaweed to make bromine like iodine, but the bromine content is too low. We can make bromine by passing ** into the brine after making salt. Because bromine exists in the form of a bromine salt, and chlorine is much more active than bromine, there will naturally be a substitution reaction to replace bromine. We can use distillation to extract bromine. Bromine is a red liquid that is easy to distinguish. We then react potassium hydroxide with bromine to form potassium bromide, and potassium bromide reacts with silver nitrate to produce silver bromide. Remember that the potassium bromide and silver nitrate reaction should be carried out under red light. Otherwise, when you see white light, the silver bromide will decompose. We also do it under red light when we develop our photos. By the way, when you do experiments, you can use a lens with a small hole for imaging. Use one shutter to control the exposure time and one aperture to control the exposure. ”

Qingfengzi said: "It's another big thing." That ammonia has taken up a lot of my people, and I don't think I'm running out of manpower right now. ”

Zhang Zhimu said: "I didn't say it, you can find as many people as possible, just bring them well." ”

"The newly recruited people are not used at all." Qingfengzi sighed and said.

Zhang Zhimu said: "Then it is even more necessary to find more people, if you don't prepare in advance now, there will never be anyone who has anything to do." ”

Qingfengzi said: "Mr. Zhang, that's right, we have to recruit more people, so that we will find that there are brains that are easy to use." It's not just anyone who can do this, the gap between this person and people is huge. ”

Zhang Zhimu said: "To engage in scientific research, you must pay attention to understanding, and it is the same as your cultivation. ”

Qingfengzi said: "What Mr. Zhang said is too good, it is necessary to have a perceptive talent." If we recruit a group of people, it would be good to have a few savvy people. Don't worry, I'll personally participate in the photo shoot, and set up a group to do this. ”

At the time of parting, Zhang Zhimu said: "Be patient with cultivating talents. Some people are late bloomers, so we should be good at discovering their strengths and encouraging them. ”

Qingfengzi nodded yes.

After Zhang Zhimu and Qingfengzi finished talking, it was already a little late. When I came to the college playground, I only saw a few male students playing basketball, because there were no lights in the classroom. Most of the students read books on campus after dinner, and the learning atmosphere was very good, but the whole school seemed very dull, not like there were more than a thousand young people here, but it was very like a group of old people gathered together. This made Zhang Zhimu feel very disappointed, and all those who were cultivated in this way would be nerds.

The dean of the college is Mr. Lu Bingyi, and the actual work is taken care of by a person from the smelter. This person used to be a Hanlin official, also called Hanlin. It is a second-class jinshi background. Because he was involved in the contradiction between the civil official group and the emperor, he was directly sent to the smelting field for labor reform. It was the last time he came to Yaogang with him, and he participated in the compilation of new dictionaries, showing a very high literary attainment. Therefore, I was invited by Mr. Lu Bingyi to be the vice principal of this school, which is actually to organize the work of this school.

Zhang Zhimu felt from the beginning that such a person might not be suitable for the management of a new school. It seems that he did let himself guess. Zhang Zhimu felt that if he had time, he should come to manage the school himself, and the most important thing was to come and see it often. Zhang Zhimu suddenly thought that he had arranged for those carpenters to make a few guitars, and he should get as many as possible and send them to the students. You can also get more other musical instruments to make everyone's spare time active. I also want the musicians of a troupe to come and teach the students.

In short, Zhang Zhimu was very unhappy after seeing the appearance of the students. Back at home, Huang Yukun heard that Zhang Zhimu was unhappy because of this incident, and said, "You don't ask the students, they can be as you imagined." Most of them have come from a hard life, and now they eat the best food, can they not study hard? That's why I'm afraid that I won't be able to learn well. How can they have the heart to play. ”

Zhang Zhimu thought about it, they had reached heaven in one step, but they were still trembling. In the future, I will go to school often to communicate with my classmates. Let the students organize more activities. Slowly turn this around. In addition, Yangchang has been running out of their electric lights for almost a month, so they can produce a batch for the school to use first. In this way, students can read and study in the evenings in the brightly lit classrooms. Dinner was made by Huang Yukun's cousin, and Zhang Zhimu did not go to the cafeteria to eat. After the meal, Zhang Zhimu just wanted to talk to Xiaoqing and Xiaohu, when Li Zhi suddenly came. Zhang Zhimu knew that there was an urgent matter again.

Originally. Li Zhi received two letters, one of which was sent by Li Mao. The other letter was brought by Ning Derang and asked Meng Si'er to bring it.

Li Zhi said: "Ning Dexin said that Sun Chuanting had been defeated, and Li Zicheng was leading the army to chase and kill. Sun Chuanting blocked all the way and retreated all the way, and now his life and death are unknown. Zhang Zhimu didn't read Li Mao's letter, so he asked Chen Yufeng and Ouyang He to come over together. ”

After Chen Yufeng and Ouyang He arrived at Zhang Zhimu's office together, Zhang Zhimu finished talking about the situation, and Ouyang He said: "Things are just as we expected, we have to shut down two warships in Tong, and when necessary, our people will be withdrawn." ”

Chen Yufeng said: "Zhimu, I think we will get the underground vault in Tongguan back." Don't be anxious. ”

Zhang Zhimu said: "I don't think it's necessary, just let them fill the basement with soil, and people can withdraw it." I feel very safe where the vault is. ”

Zhang Zhimu knew that Ouyang He didn't know that there was a vault there, so he said: "We found a vault under the Tongguan branch, which is very well hidden, so let's not move them." ”

Ouyang He smiled and said, "It seems that the silver in our kiln gang is not used up. Hehe! If it can be hidden, don't move. ”

Zhang Zhimu said: "Meng Si'er is okay, they are a group of more than 30 people, first went to Xi'an to escort Sun Chuanting's family and a group of officials' families, and even more than 300 carriages with people and goods to Tongguan safely, and then brought Ningde and their families back to Yaogang safely from Tongguan. It's really not easy for them along the way. ”

Ouyang He said: "I didn't expect that they would arrange for such family members to come over, there are more than 400 people. Thanks to our kiln, we still have this reception capacity. ”

Zhang Zhimu said: "Even if there are 400 people, I don't know how many people won it from." I don't know how many people still want to come and can't come. ”

Chen Yufeng said: "I didn't expect Meng Si'er, this guy, to be good at exercising. I can use it for one person. ”

Ouyang He said: "The environment of our kiln is to train people. However, there will be no immediate danger in Tongguan, and Li Zicheng's desire to take Shaanxi is not a matter of a day and a half, and we still have to transport the grain back as soon as possible. Food is the reassurance. ”

Zhang Zhimu said: "Our work in the previous period has made a lot of progress, and we should also summarize it. There are some new tasks to be laid out, so I think we will have a meeting tomorrow afternoon. ”

There was nothing else to do, Zhang Zhimu opened Li Mao's letter, and read it to Chen Yufeng and Ouyang He on the one hand.

Li Mao's letter talked about three things, one was that the Eight Kings once again proposed to see Zhang Zhimu; The second is that the overall structure of Fangcheng of Yangzhou Branch has been completed with cement; Third, the products sent by the kiln are in short supply, such as soap, glass mirrors, and horse lanterns are very well sold. In particular, the 10,000 lanterns that were shipped over were sold out within a few days.

Ouyang He said: "As long as we ensure the safety of the transportation line, we Yaogang people have no problem feeding the whole of Shanxi." ”

Zhang Zhimu said: "I am mentally prepared for the horse lantern thing, let's talk about those boats on the canal, if they have a horse lantern, they will not hang lanterns on the mast anymore." The horse lantern is something that the wind can't extinguish and the rain can't extinguish, and it's brighter than a lantern. Who doesn't use a few. ”

Chen Yufeng said: "It seems that Li Mao's Fangcheng can be built before the end of the year. That's it. ”

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Mechanics of Materials, Theoretical Mechanics, Elastic Mechanics, Fluid Mechanics. --Progress of "Memories of the Southern Song Dynasty".