In the history of ancient wars, there used to be a special force-elephant army, which played a role similar to modern weapons and tanks in the war. Well-trained war elephants are brave and invincible in battle. They can break through the city gate, destroy the camp, fold their weapons, set foot on the enemy line and get caught in it, often causing great harm to the enemy.
The use of war elephants was first in Southeast Asian countries, and the arrangement of elephant troops was very distinctive. There is an elephant picture on the back of the war elephant, in which a soldier is sitting, and there is an elephant driver in front of and behind the elephant. With legs as thick as four pillars, a soldier with a knife and shield stood guard. In this way, seven people formed an independent combat unit. It is said that there is a famous war elephant in Thailand. The inscription on the tablet of Rama Ganxiang in the ancient platform of Qin Dynasty records that Rama Ganxiang rode a war elephant to fight the enemy camp when he was 19 years old, rescued his father and turned defeat into victory. The fame of the elephant Rama was engraved on the stone tablet along with his war elephants. The most famous battle of elephants in Southeast Asia was 1584, when King Narixuan of Siam fought against the kingdom of Myanmar, in which hundreds of elephants were involved, ending the subordinate relationship between Siam and Myanmar.
Brief introduction of elephant
Elephant, English elephant
Mammals, proboscis, Elephantidae. Elephant, commonly known as elephant, is the largest land animal in the world. Its main external characteristics are flexible and muscular long nose and fan-shaped ears, which have the function of winding and are powerful tools for elephants to defend themselves and feed.
There are only two species of proboscis, Asian elephant and African elephant, belonging to 1 family and 2 genera. Asian elephants were once widely distributed in South Asia and Southeast Asia south of the Yangtze River in China, but now their distribution is decreasing, mainly in India, Thailand, Cambodia, Vietnam and other countries. There are also a few wild populations in Xishuangbanna, China. African elephants are widely distributed throughout the African continent and like to live in groups.
The elephant shoulder is about 2 meters high and weighs 3 ~ 7 tons. Big head and big ears are like fans. The limbs are as thick as cylinders, supporting a huge body, and the knee joint cannot flex freely. The length of the nose is almost equal to the length of the body, which is cylindrical and elastic. The end of the nostril is open, and there are finger-like protrusions on the tip of the nose, which can pick up small things. There are 1 pairs of well-developed incisors in the maxilla, which grow for life. The front teeth of African elephants can be as long as 3.3 meters, while the female teeth of Asian elephants are not exposed. There are six buccal teeth on both sides of the upper and lower jaw, which grow from front to back in turn, with high crown and complex structure. African elephants have five toes on their front feet and four toes on their back feet. However, 1 and the fifth toe are hypoplasia. The coat is sparse and the body color is light grayish brown. Male elephant testicles are hidden in abdominal cavity; There are two nipples behind the front legs of the female elephant, and the pregnancy lasts for more than 600 days. Generally, each fetus 1 offspring. African elephants have two finger-like protrusions at the end of their long noses, while Asian elephants have only 1. African elephants have big ears, big bodies and heavy weights. Asian elephants have small ears, small bodies and light weight.
From the Image of Cao Chong to the Law of Buoyancy
Reflection? Shu Wei Records:? Deng's pet son is not as smart and discerning as he is. He was born at the age of five or six, but he has the wisdom of an adult. At that time, Sun Quan once sent a giant elephant, Mao (Cao Cao). You want to know his weight, which is unreasonable under the group of people you have been to. Chong:? Put it on a big ship, engrave it on the water mark, weigh it and carry it, then can the school know? . Great joy, that is, how to implement it. ? This is the story of Cao Chong's image, which has been told through the ages and is known to all women and children.
But Cao Chong didn't create a way to weigh things by boat. According to Zi Shan, during the Warring States Period, northerners offered a sacrifice to a wild boar named Yang Xiruo in Yan Zhaowang. Yan Zhaowang sent someone to keep it for 15 years. This wild boar is as big as a grave. Its four feet cannot support its body. Yan Zhaowang was very surprised. He ordered the weighing officer to weigh it with a big scale, and the beam was broken ten times, and the weight of the wild boar could not be weighed. So, how is life in Yan Zhaowang? Stand upright, officer. Take a test. ? Zi Lang was born in Lueyang, Eastern Jin Dynasty (now southeast of Qin 'an County, Gansu Province). His five-volume Fu Zi has long been lost, and his legacy is scattered in the writings of later generations. The story quoted above is kept in the Notes on Gaizhai written by Wu Zeng in the Southern Song Dynasty. Wu Zeng pointed out after quoting Fu Zi. The method of measuring things by boat existed in Zhao Yan's time, and it didn't start with King Wargo. ? Shao, a scholar in the Qing Dynasty, also agreed.
The principle of buoyancy is used to weigh things on ships. When the principle of buoyancy is mentioned, people will naturally think of Archimedes, a famous ancient Greek scholar. According to legend, in the 3rd century BC, there was a Syracuse kingdom in Sicily, Italy. Once, King Hiro asked a craftsman to make a crown for him. The crown is made, absolutely exquisite. Hiro is very happy. He weighed it, and the weight of the crown was exactly the same as that given to the craftsman. He suspected that the craftsman had stolen some gold as heavy as silver, but he couldn't think of a way to test it. Hiro turned to Archimedes for help on condition that the crown could not be damaged. Archimedes knew that if we found out the specific gravity of the crown, we could determine whether it was pure gold or not. But the crown is irregular in shape and covered with uneven patterns. Although Archimedes was proficient in mathematics, he couldn't find a formula to calculate the volume of the crown. He thought hard for days and was at a loss. On this day, he went to take a bath. When he stepped into the bathtub full of water, the water overflowed. He suddenly realized that an object immersed in water would release the same volume of water. He finally found a solution to the crown problem. This is the story that Archimedes discovered the law of buoyancy.
Archimedes was born in 28 1 year BC and was killed by the Romans in 2 12 BC. He lived for seventy years. Archimedes used the principle of buoyancy to identify the golden crown for Silo, the king of ancient Syria. It happened in his later years. Although we don't know the exact time when Yan Zhaowang used the buoyancy principle to call the bow on the ship, Yan Zhaowang died in 272 BC, and the lower limit of calling the bow on the ship should not be later than this year, when Archimedes was only 9 years old. Therefore, Yan Zhaowang's understanding and application of the principle of buoyancy was decades earlier than Archimedes's.
But in China, Yan Zhaowang was not the first person to know the principle of buoyancy, and Mo Zhai should be the first person to reveal the principle of buoyancy. Mo Zhai was a famous scholar in the early Warring States period and a native of Lu. He founded Mohist School and wrote Mohist Classics. Mo Jing consists of four chapters: classic, classic, classic and classic. "Jing Shuo" is the annotation of "Jing" and an accessory of "Jing". Mo Jing has two paragraphs on the principle of buoyancy:
The first paragraph is great, but very shallow. ? ("Mo Jing? Xia Jing ")
The second section is heavy, and the shell of Jing is also. It is shallow, not shallow, and it is easy to become one of the five. ? ("Mo Jing? Later said ").
These two paragraphs are interrelated, among which? Jing? , should be finished? Punishment? , punishment and communication, what does this mean? Body? 、? Object? 、? What do you mean? what's up With what? What do you mean, same lift? Same? ; ? The quiet north? what's up Bay? , no, it should be? With what? . Mo Jing by Emperor Wu of the Han Dynasty? To oust a hundred schools of thought and respect Confucianism alone? Since then, it has been ignored and few people have studied it. It is not surprising that Mojing is good at ancient Chinese characters and has been circulated for more than 2,000 years.
What does this first paragraph mean? The object is very big, and the part that sinks in the water is very shallow. The reason is that the weight of an object equals and balances the buoyancy it receives. ?
What does this second paragraph mean? Put the object into the water, and the object will keep balance in the water. Even if its sinking part is shallow, it doesn't mean that it is short and shallow (but the result of the contrast between the weight and buoyancy of the object), just like commodity trading in the market, according to the price comparison, one commodity can be exchanged for five other commodities. ?
After understanding the above two paragraphs in Mohist classics, we will find that Mo Zhai has a profound understanding of the principle of buoyancy. Mo Zhai made a comprehensive investigation on the forces acting on objects in water. He saw not only the buoyancy side of the object, but also the gravity side. Buoyancy is vertical upward; Gravity is vertically downward. Gravity is the weight of an object. The ups and downs of an object depend on the interaction of these two forces. Although Mo Zhai did not explicitly point out that the buoyancy of an object immersed in a liquid is equal to the weight of the liquid it displaces, we can see the above two paragraphs, which shows that he has understood the relationship between the submerged part of the floating body (that is, the liquid it displaces) and the floating body. This is consistent with the buoyancy principle established by Archimedes in Greece.
Perhaps some people doubt that Mo Zhai could have such a profound understanding of the principle of buoyancy? Our answer is yes. Because the discovery of natural science theory is always based on social production practice. Judging from the shipbuilding industry, it is known that China has a history of seven or eight thousand years. The Neolithic Hemudu cultural site discovered in the lower reaches of the Yangtze River has been around for more than 7,000 years. Pottery boats and wood pulp were unearthed there. In Oracle Bone Inscriptions more than 3000 years ago? A boat? Words. Like a combination of vertical and horizontal components. This hieroglyph indicates that China was able to make wooden boats at that time. Even waterproof silo walls may have been invented. According to Zuo Zhuan, in twenty-four years (5 18 BC), Lu followed Wujiang as the helmsman. Then in the Spring and Autumn Period, Chu had a navy and could build warships. The remains of yachts were found in tombs in the mid-Warring States period, and a large number of iron hoops were used to assemble boards. At that time, the ships made in China were strong in structure, closely connected and watertight. In short, during the Spring and Autumn Period and the Warring States Period, China's shipbuilding industry has reached a fairly high level. At that time, if people wanted to build ships of various types and uses, they had to consider the carrying capacity of the ships, and the purpose of watertight bulkheads was to improve the buoyancy of the ships. Ship production needs people to study the principle of buoyancy. As a scholar and craftsman, Mo Zhai is good at carpentry. He once lobbied the king of Chu to stop Chu from attacking Song and went to Jiangnan, where shipbuilding was developed. There is no doubt that he has a profound study on the principle of buoyancy. It was not until Mo Zhai revealed the principle of buoyancy that it was widely used in ancient China. This is the earliest record of Yan Zhaowang using buoyancy principle to solve the problem of real number division. Judging from the inheritance of the history of science, Cao Chong claimed that the elephant was an imitation of Yan Zhaowang, while Cao Chong himself was the sprout of his wisdom. After them, there is the story of the Song Dynasty monk Huai Bing salvaging the iron cow that sank to the bottom of the river due to buoyancy.
Mo Zhai lived from about 480 BC to 397 BC. Archimedes was born 100 years after his death. Therefore, Mo Zhai should be the first person in the world to discover the principle of buoyancy. According to international practice, it can be called buoyancy principle? Mo Zhai principle? Or? Mo Zhai's law. ?
Introduction to the protagonist
Cao Cao (155 ~ 220), namely Wei Wudi. Politicians, militarists and poets in the Three Kingdoms period. The word Meng De. Pei Guoqiao County (now Bozhou, Anhui Province). When he ruled the Central Plains, he paid attention to reclaiming farmland and building water conservancy projects, which solved the problem of insufficient rations and played a certain role in the recovery of agricultural production. Appoint talents, attract the middle and lower classes of the landlord class, restrain the powerful and powerful, and expand the group. The social economy of the ruling area has been restored and developed. The method of selecting a good soldier is a brief explanation of Sun Tzu's Art of War and a summary of the art book. Good poems, such as Looking at the Sea and Though Returning to Life by Hao, express their political ambitions and reflect the tragic life of the people at the end of the Han Dynasty. They are magnificent, generous and sad. Prose is also neat. His works are included in Cao Cao Ji.
Cao Chong, whose name is Cang Shu, is the youngest son of Cao Cao. According to legend, he is a gifted child. His cleverness has won the love of Cao Cao, and he even intends to let him inherit Cao Jiajie. Unfortunately, at the age of thirteen, Cao Chong was seriously ill and died.