Shang Wen didn't care about the exercises, all he wanted to do was to use astronomical knowledge to popularize latitude and longitude. This has reached the point where it is urgently needed. Someone else sells you a large piece of land. And you can't measure it right now. Then, the legal provisions in front of you will be treated as a piece of waste paper. Such a serious test of the authority of the law.

Shang Wen in order to be authoritative for this law. They had to study, and those Shangwen themselves did not want to learn astronomical knowledge, because it contained a lot of mathematical knowledge. If you add that the explanation is not clear, it is very likely that this knowledge will be terminated.

To this end, Shang Wen first copied a large amount of relevant knowledge. It's not enough to have a lot of knowledge, you also need a lot of instruments. Especially the sextant. It is also an important survey tool for naval navigation in the future. The octave was improved into a sextant and became the mainstream nautical instrument. I still use it to this day.

Shang Wen felt the need to make both of these instruments. Only in this way can we explain to them objectively and vividly. Otherwise, they cannot be understood in the abstract. Knowledge is still too profound.

One of the more important components of the instrument is the reflecting telescope. Thankfully, glass has now been developed. mirrors, etc. Otherwise, because of the reflective material. Shang Wen had another headache. Reflecting telescopes also need to be made in a series of ways.

The observer can see the horizon at the same time through a mirror, and the angles between them can be measured with a quadrant with a scale on the edge, and the angle range can be up to 90°, thus doubling the height measured by a simple quadrant (45°) and making it an ideal instrument for measuring latitude. This is an octant.

Subsequently, the improved octanet was used as a mold to expand the measuring range to 120°, which is called the sextant, which consists of a triangular shelf with a 120° arc plate on one side with a scale and a movable pointer. The reflecting telescope reflects the two objects with angles to be measured, so that people can easily measure the angles and calculate the latitude of the ship.

This is a more simplistic measurement later. But the principle is still not clear. Shang Wen felt that he should find a more intuitive way to explain. The method is to erect a pole on the ground and draw its shadow continuously. When the shadow is the shortest, record the direction of the shadow at that time. This is due north. Measure the length of the shadow and the pole at this time, use trigonometric functions to calculate the elevation angle of the sun, and then consider the number of dates from the spring (autumn) equinox and summer (winter) solstice, and use trigonometric interpolation to calculate the latitude of the direct sun point on that day, and then add it to obtain the local latitude value.

But this requires a known quantity. But that's not all. Shang Wen hoped that his explanation would make them understand. In fact, the reason why these things can appear is due to the artillery science of the Qin State. Artillery often carried out aiming, and they made extensive use of mathematical and geometrical knowledge. Especially trigonometric mathematical functions. They have experience, but they can't make the switch. The surveying of the sapper has a good transformative power. But their level of measured cognition has not yet risen to a height. At this height, let Shangwen himself help him complete it.

Just when Shang Wen was about to compile a specific measurement method. Two Qin army officers came to the door. They were officers and soldiers of the 7th Regiment of the 1st Division. One was the colonel. One is a lieutenant and deputy company commander. And the focus of their argument is a headache for Shang Wen.

The reason is the military merit medal. The Qin state used a new incentive system. But the criteria for rewards vary greatly. The difference is that it is no longer counted in heads. Rather, it is calculated in terms of the effectiveness of the composition in the campaign. This required the Qin State General Staff to set up a special department, the War History Department. They are responsible for collecting the front and back of the battle, and then determining the effectiveness of some people based on the list provided by the field commander. In doing so, it will not only provide a large number of teaching materials for military schools. At the same time, it can also summarize some shortcomings. Compare the system, so to speak.

Military exploits are often determined on the basis of war history. Because of what happened on the battlefield. Everyone is involved, and it is impossible to know exactly what is happening to their friendly neighbors. Such is the uncertainty of war. This uncertainty is also an important reason why it is impossible to determine the attribution of some military merits. The person who wrote the history of the war was an officer himself. He tends to write according to his preferences.

"Sir, I think this ninth lieutenant of mine deserves a gold medal. And not a silver medallion. Because based on his dictation, I guess, no, speculate, that he should have shot a big shot. The colonel said excitedly.

"Oh. Can I show some vouchers? Shang Wen asked.

"The campaign has been over for a long time. There were other people on the other side at the time, and it was impossible to show the voucher, and even those bloodstains were estimated to have disappeared a long time ago. Lieutenant Nine said excitedly. The colonel was fairly restrained.

"It's a very difficult problem to do. But I'll tread the staff with investigating the matter. But I need you to provide details of the place, time, and the people involved. It is better to have their unit number, position. These I need to look up. Shang Wen said patiently.

"No problem, sir." Lieutenant Nine said cooperatively.

"Very well, you go back and submit a report. I'll pass it on to the General Staff. The Gold Medal has not yet been awarded. The main thing is that some front-line units have not yet withdrawn to their stations. But I think it will be done soon. I hope you guys can hurry up. If it is more troublesome to reissue. But I don't care, if you reissue it, I'll fight for you. Shang Wen said.

"Thank you, sir." Lieutenant Nine stood up and raised his hand and said.

"No thanks. That's right. What is the name of the ninth lieutenant. What is your role? Shang Wen asked in detail.

"My name is Class Nine Soul." Lieutenant Nine replied.

"He's the sharpshooter of our regiment. Courageous. A person crossing the battle line can shoot the officers of the opposing side. Shang Wen nodded. Expressing recognition of the addition of the head of the regiment.

"Do you like the barracks?" Shang Wen then asked.

"Of course." Lieutenant Nine replied.

"How about joining the Marine Corps?" Shang Wen continued.

"I mean, it's a whole new branch of the military. I guess you've seen it too. The probability of a large-scale war breaking out is already very low. The ensuing battles were mainly skirmishes. Therefore. This new branch of the military is responding to this situation. They needed a reliable fire support. For example, shoot the opposing commander. Are you interested in joining? Shang Wen asked.

"This." The ninth lieutenant glanced at his regimental commander.

"Sir, I need to think about it." Lieutenant Nine replied.

"Okay then." Shang Wen replied.