Until the complete system of gravity is figured out, there is no way to predict the exact arrival time of the comet whose cycle is affected by Jupiter's gravity. Pen, fun, pavilion www. biquge。 info

However, due to the early popularity of continuous dating and paper, as well as stargazing records, people who look at the stars all day can still know that the comet will reincarnate about 70 years or so, which is also a kind of inductive method.

Regarding this resentment, Jian Chen smiled: "You can rest assured, how can you get a telescope in four or five years." But if you can predict the date accurately, that's a big deal. ”

"Accurate...... Unlikely. Just a rough idea, but if your system of attraction is correct, it can be corrected for some time, faster or slower. This is also a good opportunity, get it out early, use this to prove it early, it's a rare opportunity. So you see, the two things that I was anxious about turned out to be the same thing again. ”

Mr. Motohatsu laughed for a while and said, "For us stargazers, the thing you said is useful. It's like giving us a new pair of eyes to see the stars. ”

The two of them laughed, got into the carriage, and went to a mountain by the sea outside Mincheng.

The mountain is not high, and several huts have been erected on top of it, and some materials are stacked inside.

Whether it is from the perspective of feng shui or science, the foundation of the observatory is very particular, at least to achieve the orientation of due south, north, east and west.

This doesn't need to be measured by people who look at the stars, but the groundbreaking ceremony still requires some heavyweights.

At the top of the mountain, Chen Jian gave a general introduction, and Mr. Benchu also expressed his agreement with the cement and stone observatory.

Inadvertently, among the materials of the wooden house, Mr. Honhara found a huge wooden ball, which was pierced on an iron frame.

The top of the wooden ball is covered with a layer of white paper, and the iron frame of the wooden ball is not straight up and down, but inclined at an angle.

Looking at the stars all day long, he naturally has professional sensitivity, and this oblique angle immediately reminded Mr. Honchu of the zodiac.

So he approached the ball curiously and asked, "What is this?" ”

Jian Chen hurriedly said: "Mr. Benchu must believe that the world is round, right?" ”

"That's nature. We who look at the stars, we still believe this. This is the world? ”

Looking at this big ball of white and empty space, Mr. Benchu felt a little that there was nothing on it.

Chen Jian took out a pen and said with a smile: "It just so happens that Mr. Benchu is here, and I was about to ask Mr. to pick up the pen and draw where Mincheng is." ”

Mr. Benchu picked up the pen and laughed: "How do you draw this?" ”

Then he glanced at the ball, thought about the height of the sun shadow and the angle of the North Star in Mincheng, shook his head and said, "I can only guess which arc Mincheng is on, but I don't know where Mincheng is." ”

Mr. Benchu laughed, since he knows which arc it is, then any point on this arc can be Mincheng. Once you have settled on Mincheng, you will naturally be able to settle on the rest of the places. Anyway, it's a ball, and you can't divide it up and down, but things do. Arbitrarily set a point, so that there can be something corresponding to this. Therefore, as long as Mincheng is painted on that arc, it is not wrong to draw anywhere. Elsewhere, it is naturally based on Mincheng. ”

After thinking about it for a while, Mr. Benchu understood what this meant, and laughed, and Jian Chen hurriedly handed over various measuring tools.

He found a line in the north latitude, and Mr. Benchu casually pointed a dot on it, pointing to this dot and saying, "This is Mincheng." I knew that the capital was in the north, and I knew the latitude and geometry of the capital, but I didn't dare to draw on it easily, because I didn't know anything. ”

"Mr. Honchu, things are relative, because there are magnets and North Star, and the north is cold and the south is hot. But between the east and the west, the warmth is the same, and there is no East Pole Star, this thing is only talking, it can only be relative. ”

"yes."

"Then you might as well draw another line with the help of Mr. Benchu. The meridian that runs through the north and south can pass through Mincheng. ”

Mr. Benchu seemed to have thought of something, passed the apex of Fujian City and the North and South Poles, and drew a meridian line running through the North and South.

Handing the pen back to Jian Chen, Jian took out his measuring tool and drew 36 dotted lines from north to south on the sphere like cutting a watermelon.

Jingwei Zhi said that there was as early as when he knew how to weave, and Chen Jian said that this was the warp, and Mr. Benchu felt that it was very appropriate.

"Mr. Benchu, you are a calendar master and a stargazing scholar, since you have drawn this meridian through Fujian, I think it is called the prime meridian. Based on this, the east is the east meridian and the west is the west meridian. The prime meridian passes through Mincheng. Isn't it obvious where Mincheng is? ”

"Where?"

"Twenty-eight and a half degrees north latitude, the meridian is zero. Jingwei is known, isn't it obvious where Mincheng is? ”

"Hahaha...... This longitude of yours is your own appointed. I said that elsewhere it was the zero meridian, and the location of Mincheng had not changed, but when I said it, it had changed. ”

"That's right, it's just that the thing I made first, the longitude of which thing is divided, is naturally what I say. Latitude is the creation of heaven and earth, and it cannot be changed, but things depend on people. Maybe if there is another world beyond the sea, and people have divided things, it may not be. ”

Mr. Benchu looked at this simple globe with only latitude and longitude lines and a Fujian city, and nodded: "The world is 80,000 miles wide, and maybe there is really another world that I don't know." Since the location of Mincheng has been decided, where is the capital? ”

Jian Chen laughed and said, "That's not something I can know. It's up to you, Mr. Benchu. This warp is in your name, is it possible that you still don't want to contribute? Now that there is no problem with latitude, once this longitude is determined, isn't it easy to calculate where you are and how much you are on the land? ”

Mr. Benchu recalled those complicated atlases, and pointed his finger on a dot above Mincheng and said, "About here." Sure enough, if the city of Fujian is set and the longitude is set, the city can tell where the longitude and latitude are. It's just that the latitude is easy to measure, but the longitude is difficult to know. ”

The length of the meridian has long been estimated by measuring the length of the sun's shadow at north-south intervals, and if the earth is regarded as a pure sphere - in fact, people have always done so, and only after Mr. Benchu figured out that the orbit of the glowing star was not perfect did some people have the basis for doubting whether it was a pure ball - then when we look at this ball, we can really feel that the land of China is not really large.

This intuitive gap made Mr. Benchu even wonder if there was really only such a civilization in such a vast world?

After frowning and thinking about it for a long time, he raised his head and asked Jian Chen: "You suddenly told me these things, it must not be for nothing." What are you doing? ”

Jian Chen said with a smile: "I guess you have also heard, I am going to trade in Qi Country." ”

"I heard about it when I came to Mincheng, and everyone knows it."

"I want to verify that the world is round. If it is true, as long as the sun shadow is at the same height in both places, it can be reached by going straight along the latitude from east to west. It's a route that no one has ever traveled, and I want to try it. I think there are always books that record the height of the star arrow, the length of the sun, the shadow and so on in the ports of the Qi Kingdom, but it is as vast as smoke, and it is difficult for me to find it. Mr. Motohatsu is proficient in astrology, and I must have remembered that I had read it in some book, and this is exactly what I wanted to ask for. ”

Mr. Benchu recalled for a moment, nodded and said, "There is an impression, it should be a record." ”

"If you can find a short way, it will be much easier to sail for business or anything else in the future. If you can roughly measure the longitude, even if you lose your course, you can roughly know which direction to go in the vast sea. ”

"How?"

"At twelve hours of the day and night, when the world turns, an hour turns thirty degrees. If the earth is a pure sphere, twice the meridian is the length of one circle around the equator. Knowing the latitude, the radius of the latitude is calculated by using the chord of the triangle of the moment, and the distance of one degree of longitude can be known. The time of Mincheng is inevitably different from the time of the capital, as long as you know this time difference, you can know where the capital is. Therefore, I would like to ask Mr. Benchu to do a great favor and accurately use the sun shadow to measure the exact time of Mincheng, and the smaller the difference, the better. ”

After thinking about it for a while, he understood the key and what Jian Chen meant, and asked with a smile, "Do you still need the help of one of my disciples?" Otherwise you are on the ship, how to know the time on the ship? I'm afraid I have to help you look at the star map and measure the time of the country's ports, right? ”

"That's exactly what it means."

"That's a good thing. If it weren't for the fact that I'm older, I'd really like to go and see it. But it's a pity that I'm old...... can help you find someone. I'm afraid you had this in mind when you were in the capital, right? ”

"Even if I had this in mind at that time, there was no excuse. Nowadays, the warp that separates things is marked by your character, and it has something to do with you. I, Mr. Xuegong, am too young, and not many people listen to what he says, so I can only trick you into the pit. ”

Mr. Benchu laughed and asked again: "Even so, how do you know the time of Mincheng at sea?" There is no way to transmit sound for thousands of miles in the world, not to mention the huge clocks, the time difference between the days is large, and the sea is rough and wet. ”

Chen Jian took out some things from the box that had already been pre-ordered by someone, and looked like a hand warmer commonly used by wealthy people in the cold areas of the north.

The design is very delicate, no matter how you shake it, the small bowl inside will not tilt, and it will always be flat.

"In the north, this hand-warming stove ensures that the charcoal fire does not fall out. On this sea, Sinan can be placed inside this thing to ensure that the north and south are accurate. I got someone to make some fine hourglasses, and turned them upside down every quarter of an hour, using the best fine sand, and asking the best craftsmen. ”

"There are a total of nine ships, the hourglass is matched with the flat frame of the upper hand stove, and two people on each ship are specially taken care of the hourglass, and the time of Mincheng is based on the time of going to sea, and how much time has passed and how much time is calculated in Mincheng. Nine ships, taking their average, the difference will not be too big. As long as there is a person who can accurately see the time and moment of the ship, he can calculate the approximate longitude of this time. ”

"The first time you are ignorant, but as long as you walk once, and the second time you go again, as long as the hourglass is in the boat, you can never get lost too far. Even if it deviates, it is only a hundred miles. ”

"So, the key is that someone told me about the chamfered angle between the port of Qi and the North Star, the length of the sun's shadow, the exact time of Mincheng, and a person who knows the stars and the sun and knows what time and moment it is on the ship, of course, it is best to have two, and the ship is prone to illness."

Mr. Benchu looked at Changping Sinan who had been modified from the simple hand warmer, and said with a smile: "The earthy way to make people feel shabby and cry." ”

"Helpless."

Turning around and looking at the prime meridian he drew with his own hands and the only ink dot named Mincheng that he had drawn with his own hands, Mr. Benchu smiled and said angrily: "After I come back, tell me where the port of Qi should be as soon as possible." ”