After careful observation, he found that the mountains were marked with height, the rivers were marked with width, the city walls were marked with height and thickness, and there were a few small arrows, extending from the outside of the map to the city gate. Pen? Interesting? Pavilion wWw. ｂiquge。 ｉｎfo

Li Gui hadn't ridden a horse for a long time, and finally had a chance, and was removed from the post of the chief general of the city defense, so he had been sullen after returning home, and the old problems that had disappeared for a few days came one after another, and he fell ill all of a sudden, and he didn't even participate in the royal banquet prepared by the Son of Heaven for the King of Qin to enter Luoyang.

"Report to the general, the Son of Heaven has arrived."

"Huh?" Li Gui opened his eyes suddenly, turned over and got up from the couch: "Change clothes, the old man wants to meet the Son of Heaven." The voice was actually full of anger, which surprised the maid on the side of the collapse, wasn't the old general dying in the past two days?

When Li Gui hurriedly finished changing his clothes and rushed to the hall, he saw the young son of heaven standing in front of the Luoyang city defense map by the wall, watching intently.

"The old minister sees my king."

Li Gui was about to kneel down to salute, but Ji Yan turned around and quickly supported him: "The general is exempt." Seeing that the old general was in good health, the king was quite pleased. ”

"My king came to the cold house in person, and the old minister was grateful for the five!" Li Gui said emotionally.

Ji Yan smiled and said sincerely: "For the removal of the old general from the post of the chief general of the city defense, this king feels deeply guilty! I also hope that the old general will not hold a grudge against loneliness. ”

"Thunder and rain dew, it is not Wang En! How dare the old minister have such a thought? After Li Gui finished speaking, he knelt down again.

Ji Yan grabbed his two arms so hard that he didn't kneel. "Come on, come on, this king is very interested in your map, and the old general will tell this king about it."

"Maps?" Li Gui looked at the place Ji Yan pointed at suspiciously, and suddenly realized: "My king is talking about the map!" This was made by the old minister in response to the Qin army's eastward arrival. ”

"The old general is actually a master cartographer?" Ji Yan looked at Li Gui in surprise, feeling very incredible, this rough and unruly general could actually draw a map?

Li Gui waved his hand and said, "What a master, it's just a matter of effort." I think that back then, King Xian valued the talent of the old minister, so he promoted the old minister from a military commander many times and finally became a division commander. Speaking of this, he gradually became excited, and a flush rose on his face, "The old minister is now old and frail, but he has achieved nothing in his mediocrity, and every time he thinks of the knowledge of the king, he feels ashamed!" ”

Ji Yan held one of Li Gui's arms with both hands, sent him to the desk and sat down, and then sat down on the main seat, silently looking at the old general who was stuck in memory.

After a long time, Li Gui finally came back to his senses and instructed his subordinates: "Come on, serve wine." ”

The two of them drank a few glasses in silence. Ji Yan was very uncomfortable with the wine of this era, but after drinking it a few times, he could barely swallow it now, and once again sighed at the strength of human adaptability. Li Gui was the first to break the silence: "I don't know what my king is doing here?" ”

Ji Yan said with a smile: "This king does have something to do here, but after seeing the old general's map, I want to ask you for advice on this knowledge first." ”

Li Gui arched his hand and said: "Don't dare to ask for advice." My king asked, and the old minister knew everything. ”

"Do we use wooden boards to carve maps when we march and fight now?"

Li Gui said in a deep voice: "There are very few people who use wooden boards to carve maps, and most generals are used to drawing maps on copper plates or cloth. However, the copper plate is too heavy to be carried on the march; Although the cloth is easy to carry, it is not easy to spread out on the windy battlefield, and it is flammable and wet and easy to damage, so some people use nitrated sheepskin to draw maps. Sheepskin is easy to carry, and not afraid of the wind, it is a good substitute, but it also has shortcomings, one is that it is not easy to nitrate, and the whole sheepskin will be destroyed if there is a slight difference; The second is that it is easy to be eaten by rats and insects, and it is easy to rot if it is not stored properly. ”

"Lao Chen likes to use cloth to draw maps, but he just likes it, he is not a master, and the maps he draws are only barely usable. If the king is interested in the drawing of the map, the old minister can recommend a person. If the old minister is a pawn who makes maps, he can be called a military general in this way. ”

"Oh? So powerful? Ji Yan was very surprised, how good can the map of this era be, is it better than this wooden map?

Li Gui saw Ji Yan's suspicion, smiled and pointed to the wooden map on the wall and said, "The map hanging on the wall of the old minister is carved by this person. He changed the drawing habits of his predecessors, and liked to use wooden boards, and carved them with a knife, saying that it was easy to draw, easy to carry, and easy to keep. ”

"He painted this picture? This king thought it was the masterpiece of the old general! ”

Li Gui hurriedly shook his head and said, "With the old minister's little skill, he would never be able to draw such an accurate map. He has a deep study of arithmetic, and before making the map, he must personally conduct detailed field survey and measurement, and the map made is a specific and micro actual geography, with a slight deviation in size, and the outline is accurate, and the label is clear. ”

"Good, good!" Ji Yan couldn't help the excitement in his heart, and said excitedly: "Lone is really interested, what kind of person is this?" ”

"This person's name is Li Pai, and he is in the old minister's mansion at the moment." Li Gui's face changed slightly when he said this: "This person's father was originally a superintendent of the royal house, and he had some friendship with the old ministers, but he was demoted to a serf because he made a major mistake during the reign of King Xian, and the Li faction became a serf, and he never had the opportunity to play his strengths." The old minister took pity on his plight and his talents, so he recruited him into the mansion after his father's death, and handled various military affairs related to geography for the old minister. ”

Ji Yan shook his head and said: "Whether it's humble or noble, ability comes first." This king values only talent, and nothing else. ”

Li Gui arched his hand and said: "If my king can have this mind, he will definitely make talented people in the world compete to join him, and the prosperity of the Zhou room is hopeful!" After that, he turned his head and shouted, "Bring Li to send it over." ”

In a moment, a man in his thirties came to the hall with a servant, medium height, thin stature, and two bright eyes looked at Ji Yan calmly, without any cowardice.

Li Gui said in a deep voice: "When you see the Son of Heaven, don't you bow down?" ”

Li Pai mentioned the hem of Gebu's clothes, knelt down calmly, and bowed his hand slightly: "Little slave Li Pai, see my king." "The voice is neither humble nor arrogant.

Ji Yan nodded and said, "Sir, excuse me." Have a seat. ”

Li Pai's face showed a slight surprise, and he turned his head to look at Li Gui.

Li Gui nodded slightly: "The Son of Heaven gives you to sit, you obey the order." ”

Li Pai arched his hand towards Ji Yan, and walked straight to the desk where Li Gui had started and sat down.

"I heard that this map was made by Mr. Mao?" Ji Yan pointed to the map on the wall and asked directly.

"Yes."

"How does Mr. Unknown determine the height of a mountain?" As soon as Ji Yan came up, he threw out a difficult question.

Li Pai glanced at Ji Yan again in surprise, and arched his hand: "The king can ask such a question, he must have studied this way quite well. ”

Ji Yan smiled and said: "I can't talk about studying, I just understand a little." ”

Hearing the Son of Heaven say this, Li Gui also looked at him in surprise: When did the young Son of Heaven study the way of mapping?

Li Pai sat down and said slowly: "The easiest way to measure the height of the mountain is to put up one thumb, close one eye, use only one eye to look at the mountain through the thumb, move the thumb up and down to make it consistent with the top of the mountain and the foot of the mountain, and then measure the distance from the eye to the thumb, and then measure the distance from the standing place to the foot of the mountain, the ratio of the two distances is the ratio of the length of the thumb to the height of the mountain." ”

Ji Yan squinted his eyes and thought about it, and found that this measurement method skillfully used proportions, converting the measurement of height into the measurement of distance, and couldn't help but look surprised: "Sir, this method is really simple and practical. ”

Li Pai was even more surprised: "The king actually understood when he heard it? ”

"Yes, Mr.'s method is simple and easy to understand. For example, if the distance between you and the mountain is one mile, and the distance between your thumb and your eyes is one foot, and the ratio of the two distances is fifteen hundred, and your thumb is about two inches, then the height of the mountain is 1,500 times that of two inches, which is thirty zhang. ”

Li Pai stood up and arched his hand: "The wisdom of the king amazes the little slave!" ”

Li Gui frowned on the side and said, "How is it measured?" The old minister was still confused. ”

Ji Yan and Li Pai looked at each other and smiled, which made Li Gui even more confused.

Ji Yan asked Li Pai to sit down and asked, "Is the height of the sky measurable?" Is the thickness of the ground measurable? ”

Li Pai straightened his posture and said loudly: "In the past, Zhou Gong once asked Shang Gao: I heard that the doctor is good at counting, may I ask the former to set up the Zhou Tian calendar - the husband can rise without steps, and the earth cannot get the size and degree, may I ask the number of people?" It is exactly the same as the king's question. ”

After a pause, he continued: "Shang Gao replied: The law of numbers comes from the circle, the circle comes from the square, the square comes from the moment, and the moment comes from the ninety-nine-eighty-one. Therefore, the moment is broken, and it is thought that the sentence is wide three, the stock repair is four, and the diameter corner is five. Both square, the outer half of its moment, ring and a total plate, into three, four five. The total length of the two moments is twenty and five, which is called the product moment. Therefore, the reason why Yu rules the world is that this number is born. Shang Gao's answer perfectly explains how to measure the thickness of the sky. After Li Pai finished speaking, he stared at Ji Yan without blinking, in his mind, such a profound calculation method, this pampered son of heaven would not understand it anyway.

Ji Yan sorted out Shang Gao's answer in his mind, and couldn't help but be surprised after figuring it out, isn't this Nima the calculation method of hooking three strands, four strings and five? This era will be able to prove the Pythagorean theorem?

Seeing the surprised expression of the Son of Heaven, Li Pai smiled and said: "This algorithm is quite profound, those who are not proficient in this way cannot know it, and it is common for the king not to know the truth, so don't be surprised." ”

Ji Yan shook his head and threw the shock out of his head, but he didn't tell that he was not surprised because he didn't understand, but his face was straight, and he said to Li Pai: "Mr. is really talented, this king wants to invite you to be an official in the court, I don't know if Mr. is willing?" ”

Li Pai looked at Li Gui with a happy face. Li Gui was also overjoyed, but after thinking about it, he frowned, and said to Ji Yan: "It is his blessing that my king is willing to appoint the Li faction, and the old minister is also happy to see it." It's just that Li Pai is a serf, and I'm afraid it will be inconvenient to be an official directly! ”

Ji Yan waved his hand: "What's wrong with the serfs?" If Lone wants to use him, who can say anything? He looked at the surprised expressions of the two, and thought that the class distinction in this era should not be ignored, even if he is the son of heaven, it is not easy to make a mistake, so he said, "In this way, this king orders to remove your serf status and give you a countryman status." ”

Li Pai hurriedly came to the hall, knelt down gratefully, and said: "The king is reinventing the little slave, and in the future, he will saddle up the horse and the horse will be driven." ”

Ji stretched his hand and held his hand: "Sir, don't call yourself a little slave in the future, this king will give you a job as a surveying doctor, and the preparation will be temporarily placed in the Winter Official Mansion, which is the same as Situ Doctor Simu, but directly under the jurisdiction of this king, for this king to survey geography, draw maps, and look for minerals." ”

"No." Li Pai solemnly bowed, and then got up and sat back, his face full of excitement.