How to make a celestial gazetteer? This question put Shang Cheng to the test.

He had seen astronomical telescopes. Not in photographs or films, not in the observatory, but in the factory. Next door to his dormitory lived an amateur astronomer who had an astronomical telescope in his hand, and sometimes when he got bored, everyone would take that thing and look around. He still remembers that at the beginning of 07, there was a total lunar eclipse, and he and a few people ran to the roof of the factory office building and used the telescope to open their eyes. It is said that the astronomical telescope is not very expensive, only three or four thousand yuan. It's a pity that I didn't pay close attention to the details of that telescope. Now, Tian Xiu asked him how to make the celestial sphere, but he really couldn't answer, so he could only say in general terms: "There must be a bigger lens and a bigger body." ”

Tian Xiu was a little disappointed. It's an unexpected answer, but it makes sense. At least she had never heard of anyone in history who had made a celestial sphere out of glass, so Shang Cheng admitted that he would not make such a celestial sphere, and she didn't think it was strange. She was disappointed that she had thought that Shang Cheng might know something, and these things could give the Ministry of Industry a shortcut when making the Celestial Observatory...... She stood silently for a while, then raised her hands and made a formal gift to Shang Cheng, who helped her a lot. Although it may be far from being successfully cast at the moment, the idea of making a celestial sphere with glass lenses has been empirically proven, and the next step is to make the "geosphere" that can only see the illuminated archway to observe the stars on the celestial dome...... She was about to move, when she suddenly realized something. Yes, no one has ever made a celestial sphere out of glass before, but there is no book that says that the sand in the river can be used to make glass! She also carefully researched that there was no such thing as "glass" before. She suspects that perhaps even the term "glass" was taken from "glass" and "glass" respectively, and then made up by someone and placed on such an unprecedented thing as glass...... Who this lyricist is, I won't mention it. This person also has a problem, that is, he has always liked to pretend to be muddy, even if he puts forward the idea himself, he is likely to die and refuse to admit it afterwards, and would rather write a note to admit his mistake and apply for punishment from the imperial court, rather than be reluctant to give a few more words. This is the case before and after the glass incident, and the celestial gazetteer in front of you is even more proof! Therefore, you must not be gullible about all kinds of prevarications about this person, otherwise you will inevitably end up regretting and resentful! Thinking about this clearly, Tian Xiu immediately changed her mind.

She immediately stopped her steps, put her left hand on her right hand, and put her hands in front of her, bowed her head slightly, and held her breath to say nothing.

Shang Cheng didn't notice at all that Tian Xiu was performing the disciple ceremony. He just felt that Tian Xiu didn't move after saluting, and felt a little strange, so he asked curiously, "Are you still in trouble?" ”

"Yes." Tian Xiu lowered her head and said. But she didn't say anything about herself, because Shang Cheng didn't ask. The elders have questions, and the disciples have answers; When the elder asks, the disciple answers. Otherwise, it is "answering the wrong question", one by one, which is disrespectful to the teacher!

"What's the matter?" Shang Cheng asked her. He didn't want to ask about it. Does this still need to be asked? It must be a problem that even the Ministry of Industry can't solve. What can he do about the problems that the Ministry of Industry can't solve? But he didn't want to be cold, so he had to take a step for Tian Xiu. He thought like this: if he can help, he can help, and if he can't help, of course, he can only ask Tian Xiu to figure out a way by himself.

"It's ......"

"Sit down and say!" Shang Cheng pointed to the chair next to him. This is eating in a restaurant, not working in the yamen, he is sitting and Tian Xiu is standing, and the way the two of them talk like this makes him feel very uncomfortable. While letting Tian Xiu sit down, he reached out to take the teapot, wanting to refill some hot tea soup for himself and Tian Xiu's cup. He only noticed now, and he didn't know when, the maids and maids in the private room had withdrawn. He shook his head and praised in his heart, this slender lady is really capable, and Linyuan Pavilion can be regarded as a treasure.

His hand hadn't touched the teapot yet, and Tian Xiu, who hadn't yet sat down, had already snatched the teapot into his hand. She held the teapot with both hands to refill Shang Cheng's cup with tea soup, and added a little to her own pot shallowly, put down the pot, and sat down on the chair very respectfully, just like a student waiting for the teacher to teach and solve his doubts.

Shang Cheng glanced at her suspiciously. Tian Xiu put on a serious expression and sat solemnly on the chair, which made him feel as if he was not in some restaurant now, but in the main hall of the Yanshan Admiral's Mansion to gather his subordinates for a meeting. But he couldn't say anything, so he could only pick up the lamp and drink water, waiting for Tian Xiu to talk about the difficulties faced by the Ministry of Industry in the production of glass and the manufacture of the celestial sphere.

Before he put down the teapot, Tian Xiu had already stood up again and picked up the teapot.

Shang Cheng was simply annoyed by her sudden excessive enthusiasm. He held the lamp and said to Tian Xiu, "You sit down!" I'll pour the water myself when I drink it one by one. You ......," he paused, swallowed back a less pleasant remark, and in a more soothing tone, continued, "Tell me, what problems are you all having now?" Let me start with an ugly word, my major is not here at all, so whether it is glass or astronomical telescopes......" Shang Cheng's words paused abruptly. Damn, he inadvertently said something he shouldn't have said again! Fortunately, there were only four people in this room, Chen Pu and Shangguan Rui were still holding a few lenses and gesturing in front of the window to talk about something, and Tian Xiu didn't seem to notice the negligence in his words at all, and he didn't say anything or look up. Only then did he finish his words, "...... Whether it's glass or the celestial sphere, I don't know the details of these two things, so I can't help you much. Don't put your hopes in me. ”

"Yes. I know. Tian Xiu whispered, "Now, our first problem is that there are bubbles in the glass. This has been going on since the glass was first burned, and there is no way to solve it until now. I would like to ask you, how can I avoid bubbles in the glass? ”

Shang Chengba smacked his lips and was silent for a long time before he said, "What, do you have anything else more tricky?" He felt that the difficulty of the question was too high. The bubble problem in the glass production process is a big problem in the glass industry, and it has not been completely solved for hundreds of years, let alone the fledgling glass workshop.

If the elderly have a question, do they dare to answer? Tian Xiu immediately raised something that seemed more difficult to her: "You mentioned that real glass must be colorless and transparent. But now we burn glass, colorless and transparent is very rare, nine out of ten stops are divided into red, purple, red, green, green, yellow, white, brown, black, blue ten colors. How should this be addressed? ”

The question is simple. Shang Cheng said with certainty that this is the raw material of glass that contains impurities. There are probably iron filings in the red and red glass, the green and cyan should be inseparable from the copper element, and the purple color is probably the common reaction between iron and other metal elements; The same goes for the rest of the colors. There are also many solutions, such as finding better quality quartz deposits, such as avoiding the use of the same means of transportation with other raw materials as much as possible, such as strengthening the system of transportation, storage and use of raw materials, such as speeding up more efficient production equipment......

Tian Xiu remembered it attentively. After Shang Cheng finished speaking, she immediately asked a series of new questions: What is an element? How is copper related to copper, and how do they differ from each other? Why does copper make glass blue and green in color? Since there are "metallic elements", are there other elements that are not metals? "Copper" and "iron" are both "gold" in the five elements, so is this so-called "metal" the "gold" of "gold, wood, water, fire, and earth......

A lot of questions made Shang Cheng's mind a little confused. Let's not talk about whether he can answer these questions one by one, the key is that he is talking to Tian Xiu about the affairs of the Ministry of Industry, why did he suddenly climb into the metal element? He could only mutter: "You get the glass thing done first, and I'll tell you when the elements have time!" ”

At this time, Chen Pu and Shangguan Rui had already sat back on the side of the case. Both of them were keenly aware that Tian Xiu was asking Shang Cheng for advice as a disciple, so they didn't bother them, just fiddled back and forth with a few lenses, and whispered a few words from time to time.

In order not to annoy Shang Cheng and become angry, Tian Xiu immediately cut off the topic and turned to the Heavenly Observatory. The Taishi Bureau hopes to cast a total of 20 glass celestial viewing instruments of 5,000 catties in bronze, but neither the Ministry of Industry nor Ouchi knows how to start now. At present, the casting of large bronze vessels or iron vessels, including several large planetarium of the Taishi Bureau, such as the celestial observation and armillary sphere and the geodynamic instrument, etc., are usually burned out of the clay first, and then cast in sections and sections in part and in the end; This is the mud fan ming pouring method. However, the new glass celestial observatory, with its large hollow bronze tube weighing 5,000 catties, needs to be cast successfully, which stumps everyone. She wanted to ask Shang Cheng, how to start the casting of this bronze tube?

As soon as he heard this weight, Shang Cheng was in awe of the Taishi Bureau at that time. The 5,000-pound hollow bronze tube, what I know is that the Taishi Bureau wants to build a celestial orb, and those who don't know must think that they want to build a bronze cannon! He smiled and said, "Five thousand catties or anything is completely unnecessary." I estimate that if you use glass lenses to make a celestial orator, at the beginning, a few dozen catties of bronze is enough, and you may not be able to use it up one by one. Of course, the final amount of weight is determined by the lenses. In order to make the celestial observatory see farther and clearer, the mirror body will inevitably need to be longer, and its weight will naturally rise. He pointed to a few teacups. It's hard to say the size of the convex mirror, in case the requirements of the Taishi Bureau are high, and you have to rely on the naked eye to explore the world outside the solar system, then it is not impossible for a lens to cost tens of thousands of catties. But the concave mirror must be smaller, preferably not more than the bottom of this teacup; It would be even better if it could be done to the size of a person's eye. In this way, when you observe the sky through the celestial scope, you are not easily affected by the things around you. ”

"However, the glass lens ......"

"Yes, polishing glass lenses is also a problem." Shang Cheng didn't wait for Tian Xiu to finish speaking, so he interrupted her. "You're looking for a craftsman who polishes the jade, so there's definitely nothing wrong with their craftsmanship, the only question is whether they can polish the lenses according to your requirements."

Tian Xiu nodded. This is also the problem that has been bothering them for a long time.

"The solution is simple, just set a standard that everyone can understand. If a glass lens is round, it has a circumference, radius, diameter, and thickness. For example, if we now take the pair of convex and concave mirrors in Chen Zhuguo's hand as a benchmark, calculate the ratio between their respective circumferences, radius, diameters, and thicknesses, and fix this as a benchmark, then it should be easy to get the same lens. The Ministry of Works can also make simple tools that can be used by craftsmen and officials to measure and correct ...... at any time."

Tian Xiu clapped his hands, and then reacted that he was a little forgetful, and quickly stood up to apologize to Shang Cheng, but the joy on his face could not be concealed no matter what. Her mind is flexible, and as soon as Shang Cheng said, she immediately outlined all kinds of rules in her heart, and extended many methods. The Ministry of Industry has now also obtained the simple method of using numbers from the Ministry of War, one by one, it is said that this number was pioneered by Shang Cheng, but he himself has never recognized this account, one by one, he can set a certain ratio to the starting value of "zero", and then make the convex mirror a positive number, and the concave mirror is a negative number, and then according to different positive and negative values to make a large piece of glass lens, and slowly find the most suitable lens combination for making a celestial viewing sphere!

Shang Cheng also added two more supplements to her. First, since there must be a difference in distance between the distances that can be observed by different lens combinations, the Ministry of Industry should establish a special document file to record the effects of various combinations in detail and indicate the scope of application of such combinations. Again, there are only two parts of the mirror body made by the Ministry of Industry now, the copper pipe and the copper cap, which is very inappropriate; It should be divided into three parts, and a copper cap should be added to the front of the copper cap to fix the lens, so that even if there is a problem with the lens, it will be easy to replace; The screw buckle at the junction between the large copper cap and the copper tube should be thinner and longer, so that people can make slight adjustments when using it, just like everyone just held the two lenses to adjust the position before and after. Also, if the weight of the celestial sphere is not so unbelievable, the base can be changed to an iron or wooden tripod, which is easier to move. Of course, if the Taishi Bureau is rich and rich, and still takes out 5,000 catties of bronze celestial instruments to build twenty in one go, and has to build one hundred and ten celestial gazetteers, then it will be as if he has never said anything......