Chapter 281: globe

There was a hangover all night, and when he got up early the next morning, Xiao Ming's head still ached.
Today is the first day of the new year. According to the custom, when visiting relatives and friends, if he is in Chang'an, he should visit everywhere.
However, if there is no important matter in Dayu State, the prince cannot leave the fief, especially Xiao Ming who is still responsible for guarding the border, let alone leaving his post without authorization.
Now that New Year's Eve has passed, for Xiao Ming, the first thing that happened during the New Year was the sailing of the Galen ship.
Arranged to spread the drama secretly to the people, he went to the Bowen Academy, and other people could rest during the New Year, but Yue Yun could not.
After all, he will be the leader of the three Galen ships.
"His Royal Highness, is today the last lesson before going to sea?"
In the morning, Yue Yun was waiting in the school.
Xiao Ming nodded. He told Yue Yun not to go to sea for the time being. There were two reasons. One was that the artillery hadn't been on board yet, and the other was that Yue Yun still lacked the most important lesson of sailing—how to locate his position on the sea. .
There are only three people in the school, one is Yue Yun, and the other two are the two sailors who have learned better among the seafarers this time. The position Xiao Ming gave them on the sea is the navigator.
As the name suggests, the job of the sailing ship is to locate the ship and guide the Galen ship to the right direction.
Sitting down in front of the three of them, Xiao Ming said: "You can't finish these things in one lesson. Remember, the things you are going to learn below are very complicated, so please cheer up the king, otherwise you may get lost. Never come back on the sea."
Upon hearing this, the three Yue Yun nodded their heads, because Xiao Ming had never been so serious in the school.
At this time, Xiao Ming stretched out his hand, and a princely family member walked in, holding a ball-shaped object in his hand, and a stick pierced through the center of the spherical object, with the ground at the bottom.
"You used to ask this king what the world is like, and now the world is in front of you." Xiao Ming pointed to the globe on the table.
This is what he has been preparing during the Chinese New Year. The globe is pure wood, and the outside is polished smooth. The longitude and latitude of the earth and the world map are marked on the globe, especially the vertical and horizontal navigation routes, and even where there is a reef. .
The map also marked the special products of each region, not as good as corn, cotton, sugar cane, gold and so on.
"His Royal Highness, is this the globe you are talking about?" The three Yue Yun were shocked.
What this globe shows is definitely a subversion of their thinking.
Xiao Ming nodded. The globe is one meter in diameter, and there is enough on it to draw a map of the world.
In order to draw this map, he destroyed more than a dozen globes, until this was a little more perfect, he used it directly, otherwise he would not wait until now to teach Yue Yun this knowledge.
Xiao Ming's hand clicked on the globe, the globe began to rotate, and pieces of ocean and land flashed in Yue Yun's eyes.
"From the simplest point of view, first of all you have to do which oceans and which land the world is divided into." Xiao Ming began to talk about the four oceans and seven continents and instilled in Yue Yun.
It can be said that his current education is basically a duck-filling education, there is no way, some things can only be memorized, and this is his strong point.
While talking, Xiao Ming showed the location of these regions on the globe, explaining the knowledge of every land in the world in great detail.
After popularizing the knowledge of world geography, Xiao Ming said it was punctual.
"Now that you know that the world is big and there are many countries, it's time to teach you how to locate at sea." Xiao Ming said.
The three Yue Yun had become very humble now.
During this period of study, they felt that they were nothing more than a frog at the bottom of a well, and they no longer had the arrogance at the beginning.
"This is a quadrant."
After the globe, Xiao Ming took out the same item that is necessary for navigation in this era, the quadrant. The real name of the quadrant in his hand is the Davis quadrant.
This kind of quadrant was invented by British navigator Davis at the end of the 16th century to measure the latitude of the earth while sailing.
According to records in the Science and Technology Library, this quadrant was the most accurate navigation tool of this period from the 16th to the early 18th century.
Moreover, this kind of quadrant is simple to operate. It is not necessary to pull a rope like using an astrolabe to see the sun. Instead, use the shadow projected on the scale by a stick. The position of the shadow end indicates the height of the sun, so that the latitude can be calculated. Up.
When making this quadrant, Xiao Ming has done a lot of work. In fact, the structure of this quadrant is very simple. It is composed of two compasses, one large and one small, but each of the two legs of the compass uses a curved wooden bar. Connected, and each connected structure has a wooden stick.
The most rare part of the quadrant is the scale problem.
In order to make the scale accurate, the quadrant in Xiao Ming's hand is a little big, almost fifty centimeters long.
After all, the larger the scale interval, the better the drawing, and the error is relatively small.
"His Royal Highness, do you use this to calculate the latitude of the earth?" Yue Yun already understood what latitude and longitude are.
Xiao Ming nodded, "This is just an instrument. Now you have to learn how to calculate latitude and longitude, which is the formula for latitude and longitude."
After that, Xiao Ming got up and stood in front of the blackboard.
He wrote on the blackboard, "1 degree of latitude = about 111km, 1 minute of latitude = about 1.85km, 1 second of latitude = about 30.9m, 1 degree on the longitude = 111 kilometers, 1 degree on the latitude = 111 cosA kilometers, where A is the latitude, the distance between any two points, d = {1/[sinΦAsinΦB ten cosΦΦ(λB-λA)]}."
As soon as this formula came out, Yue Yun's entire head was big. He held his head in pain, "His Royal Highness, can you not learn these things."
"No, Xiao Ming answered very concisely~EbookFREE.me~ The mathematics of Yue Yun's and others can be said to be zero. Now it is impossible to learn advanced mathematics at once in the past few months, so Xiao Ming will not teach Yue Cloud other mathematical knowledge.
He only let Yue Yun learn how to calculate latitude in this way, which means he only needs to learn how to use this formula to calculate latitude and longitude.
In this way, his learning volume will be greatly reduced, and he will only focus on this formula.
And Xiao Ming will also provide him with a calculation table of latitude and longitude. Even if he can't figure it out at that time, he can determine his position by looking at the calculation table of latitude and longitude, so that he will not run off at sea.
In the past, Xiao Ming also thought that sailing was a very simple thing, but after studying the knowledge of navigation, he realized that this is a very complex system of knowledge. In the 18th century, walking along the coastline was not called navigation.
The current course is basically the last course after Yue Yun went to sea. From then on, he will go to the sea, for trade, for the boundless wealth, and for Qingzhou's most primitive capital accumulation.
(To be continued.) Enable new URL