When the wind comes, Mengdong, the scenery is depressed and empty, in the eastern suburbs of Shangcai in early October, there are a few more cars to ride on this day, Zhang Han and Qin Mocheng Shang take a car, Heifu is on horseback, under the protection of hundreds of soldiers, left the camp and went east.

The speed of the emperor was very slow, so that the military secretary Zhang Han carefully observed the surrounding terrain, and when he reached a certain area, Zhang Han shouted: "Stop!" ”

The camp pays attention to the choice of land, and the same is true for the construction of the wall, Hefu saw that there was grass on the left, a spring on the right, and the danger of the hill on his back, but the vision facing the east was very flat, and there were roads passing by, and there were woods and meadows for woodwork and grazing several miles away, which could be described as a place of four preparations.

Heifu looked at it and said: "Isn't this what Li Duwei said about the eastern suburbs, I heard that back then, Tingwei father and son were several people, and they often led yellow dogs to chase cunning rabbits here, which is indeed suitable for camping and building strongholds." ”

The work of building the barrier to be done now is also Zhang Han's duty of "handling the army".

The "series" of the "Divisional Military Collection" is the meaning of the security series, which means that after the barrier is built, the army can be stationed with peace of mind without fear of the enemy's sneak attack or strong attack; If the construction tasks are distributed fairly and reasonably, there will be no confusion and contradictions as a result.

While talking, Zhang Han also got out of the car with everyone, and began to hold quasi, rules, rules, ropes and other instruments, and began to carry out construction surveys on the endless Shangcai Plain.

Zhang Han lifted the "quasi" of the hanging weight, got out of the car and tried to be straight, comparing the difference between the height of the terrain. Cheng Shang pulled the walking rope and carefully measured step by step on the ground, and there was a Shuzuo next to him who was recording the distance.

As for the "rule", it is a tool for correcting the circle, and the tool for drawing a square "moment", that is, a curved ruler. Zhang Han and Qin Mo have already played this simple tool out of tricks, which can not only determine the level, altitude, depth, distance, but also draw a circle and draw a square, and place it in different positions when used, and can also measure the height and distance and size of the object, as for how much error is, it all depends on the experience of the operator.

Seeing that Heifu was curious, Zhang Han also explained: "It is said that when Yu controlled the water, Yu traveled by land, by boat, and by mud. The mountain line is taken, the left line is the line, the right is the rule, and the four lines are carried to open Kyushu and pass the nine roads. ”

Although this is a legend, it is most likely that the world attributed the tools invented by the skilled craftsmen to the holy king, and in this way, it took them half a day to measure the sections of the fortification, and every hundred steps, they also inserted blackened wooden poles deep into the ground as markers.

After returning to the camp in the evening, with the data measured today, Zhang Han asked several senior accountants who were proficient in arithmetic to calculate the amount of work, so that they could be assigned to the Minfu Brigade for construction.

Heifu was fortunate enough to see the dazzling quantity calculations of this era.

I saw that a large number of calculations were placed on the ground in the open space of the camp tent, and this thing Heifu was no stranger to, because the Qin State stipulated that local officials must have calculations to deal with unexpected needs. Mathematics is one of the six arts of the Spring and Autumn Gentleman, the necessary skills of Qin officials, in the local officials, Fangtian, corn, average loss, taxes, must be calculated a large number of numbers, if a person does not know the number, even the qualification to be a fighting official!

In Xianyang and the county seats, there are also special "accountants" who calculate the annual household registration, taxes, land reclamation, money valley, thieves, prison lawsuits, etc. of each county, and borrow funds to evaluate their performance, which is called the upper count. These people were equivalent to the accountants of later generations, and their daily work was to deal with numbers, and the accountants were also called up in wartime as specialized personnel, as military officers or military officials (logistics officers). Help measure the height of the hillside, measure the depth of the river, coordinate the weight of corn, and dispatch the number of divisions and brigades.

At present, the tellers were sitting in their tents, sweating profusely and fiddling with their calculations, and the black man looked over and found that they were all calculating, "There is a trench today, one zhang and three inches in the upper width, one zhang in the lower width, six feet three inches deep, and thirteen zhang and two feet and one inch in width." Ask product geometry? "The merit is 766 feet, and the unearthed merit is one-fifth, and the fixed merit is 612 feet and four-fifths, ask the apprentice geometry?" problems.

Although the planners were quick to fiddle with the calculations, in Heifu's opinion, it was still very complicated and troublesome.

Zhang Han didn't have this feeling, but said with a smile: "In the past, it was more complicated to count the soil work and the number of people, but fortunately, there was an official in charge of books and classics in the Imperial History Mansion, according to the actual projects such as building city walls, digging ditches, and building cellars......

The so-called business merit is the method of measuring the volume and calculating the labor of the project, and Zhang Han also showed Heifu the volume of "Shang Gong" that he carried with him, and each part is divided into problems, solutions, and formulas.

Heifu looked at it, and only felt familiar, isn't this the nine-chapter arithmetic!

"Shaorong, the official you are talking about, is it called Zhang Cang?"

"Oh?" Zhang Han was a little surprised: "The leader also knows Zhang Cang?" ”

"Xunzi Lanling apprentice, I have heard of it for a long time."

Heifu smiled: "Moreover, I used to be a Hugu tour in Yangwu County, Dangjun County two years ago, and I met Zhang Cang's two uncles, Zhang Cheng and Zhang Bo, and I also heard about the deeds of this Zi Gu from their mouths, I never thought that he was so talented!" ”

"This is natural, Zhang Zijun is omniscient and omniscient."

Zhang Cang is Li Si's junior brother, and he is also a member of the "Li Si Party", and as a Shaofu official, many things involve precise calculations, Zhang Han has dealt with Zhang Cang a lot, so he talked about an interesting thing about Zhang Cang:

"When Zhang Cang first came to serve in the Imperial History Mansion, the Imperial Doctor saw that he was born white and fat, and it was a little inconvenient to even move around, so he was quite disliked, so he pointed to his round belly and asked, what is inside? Zhang Zijun didn't think it was angry, only patted his belly and laughed and said, what is contained in it is all knowledge, and it is full of economy! ”

"Doctor Yu Shi is also a great talent who is rich in five cars, and immediately took the exam for Zhang Cang some questions, and answered them all, and even some of the classics that are out of the door, even the doctor of Yu Shi has not read them, so he asked him to take care of the books in the library. Zhang Cang is a book-lover, often with a little dry food, just sit in the pile of slips for several days, and now I am afraid that the Han, Zhao, Wei, and Yan collections of books collected by the Imperial History Mansion have been read, and everyone said that seeing that his belly is getting fatter and fatter, I am afraid that he will put all the knowledge of the whole world into it? ”

Thinking of that guy who was extremely smart, but getting fatter and fatter, Zhang Han couldn't help laughing: "When I went to Xianyang in the future, I know what kind of person he is!" ”

"Definitely!"

Heifu was amazed in his heart, most people are dead readers, but Zhang Cang not only dabbles in a wide range of knowledge, but also can turn what he has learned into practical application, which is very remarkable.

He glanced at the planners who were quickly fiddling with the calculations, and said secretly: "If there is a vertical algorithm of Arabic numerals and an abacus, the calculation of these engineering quantities should be much faster." ”

However, Heifu did not rashly offer treasures, those knowledge, he actually only left the mathematics level of junior high school students, teaching to ordinary people is not of great use, I want to go to Xianyang in the future, and then find an opportunity to reveal it to Zhang Cang, I don't know if it can bring a mathematical revolution to this era?

……

After calculating the amount of work, Zhang Han assigned work to the 10,000 people of Nanjun who were assigned to him, and they were responsible for the construction of the three-mile barrier, so throughout the beginning of October, the suburbs of Shangcai became a large construction site, and the loess was all over the sky, and thousands of people carried the soil......

The walls were built using the same method that Heifu had participated in in Anlu County, and thousands of other people skillfully used tools to cut down the trees in the forest near Shangcai, and after the branches were removed, they were sawed into pieces, and finally nailed into planks. When the version was full of soil, the people picked up the heavy ramming pestle and smashed it according to the loose cooked soil! The sound of the trumpet in full swing shook the four fields, and it was basically a layer of building every day.

The leaders of the Heifu and their soldiers, with their soldiers, waited outside the construction site in full gear to deal with the attack of the Chu army that might come at any time.

"Isn't this a way to lure the enemy?"

On the border between Qin and Chu, tens of thousands of Qin troops protected tens of thousands of people, and they were ready to fight at all times, for fear that the Chu army would not come.

The cavalry sentinels of the Chu State were also watching this scene from afar, but the main army never dared to attack rashly, because Xiang Yan knew that this might also be a trap laid for him by Wang Qian.

A few days later, a thick earth wall with a height of more than a foot appeared out of thin air in the eastern suburbs of Shangcai, rising from the ground, and where the benchmark was previously inserted every 100 steps, Zhang Han was also urging the people to build taller and stronger corner towers.

It was at this time that an accident occurred......

A freshly rammed corner tower, Zhang Han led people to test its firmness, but after more than ten people carried the wooden stake and hit it a few times, there were traces of cracking! And a large number of clods of dirt fell off!

"If the Chu army comes to attack, how can this corner tower resist the enemy? It will definitely become a gap for the enemy to break through, and the embankment of a thousand miles will be destroyed in the anthill! ”

"Those who repair this corner tower will be whipped ten times, and then they will be knocked down and rebuilt!"

Zhang Han glared fiercely at the official in charge of this paragraph, and said that if there is a second time, the person in charge will be beheaded, and the rest of the people will also die!

Sikong Xiaoguan was submissive, and Zhang Han said to Heifu with some distress: "The history of the superintendent requires that the corner tower must reach the hardness of the wall in Guanzhong and be indestructible, but it took a long time to ram out, and the current construction period is only more than ten days, and it may be difficult to ram it in a hurry." Moreover, the quality of the soil is directly related to the solidity of the fortress corner tower, and it is better to have fine but not loose soil, moist but not dry, bright and not dark, but the soil of Shangcai is really average, far less easy to use than Guanzhong loess......"

In this year, Cai's forest coverage rate is relatively high, and there is a lot of humus in the soil.

Zhang Han decided to let people go near and far, and dig dry and loose loess from a distance to repair the corner tower, so as to ensure the quality, Heifu rolled his eyes and gave Zhang Han an idea.

"Shaorong, in Anlulilu, Nanjun, there is a kind of soil method, which is used to repair houses, which is extremely hard after drying, not only does the water not change, even iron nails are difficult to drive in! Hundreds of years of wind and rain are still intact! ”

After speaking, he was afraid that Zhang Han would not believe it, so he took out his sister-in-law and took the blame: "My sister-in-law is not only proficient in carpentry, but also has used this method to repair houses for people. ”

"And this way?" Zhang Han was immediately interested, and asked Heifu to elaborate.

Heifu smiled, this is a common method of building houses in rural hometowns in the previous life, which is not popular in this era, so he pointed to the bubbling Rushui tributary not far away: "It's very simple, and the material is not rare, with common loess, plus fired mirage, river sand mixed with ramming, it is called Sanhe soil!" ”