Four Great Inventions

1 Compass

One of the four great inventions in ancient China. A pointing instrument made by utilizing the north-south polarity of magnets in the earth's magnetic field. It comes in many forms. During the Warring States Period, the phenomenon of magnets attracting iron was discovered, and natural magnets were used to make "Sinan's Spoon" and "Handle Guide". After that, after a long period of practice, the method of artificial magnetization was discovered, resulting in a higher-level magnetic pointing instrument. Shen Kuo, a scientist in the Song Dynasty, first recorded the geomagnetic declination. He said that rubbing a steel needle with a natural magnet made it magnetized into a magnetic needle, which could guide the needle, usually slightly to the east. He also introduced four methods of hanging a magnetic needle: one is to float on the water; The second is placed on the nail, the third is placed on the rim of the bowl, and the fourth is hung with threads (see the color picture of the thread hanging method of the compass copied according to Shen Kuo's records). The Song army was equipped with guide fish, which were thin iron leaves cut into fish shapes and magnetized. They were used to determine the marching direction on cloudy days and nights. Later, it developed into a compass disk with a magnetic needle and an azimuth disk integrated into one, that is, a compass. Zeng Sanyi recorded in "Yin Hua Lu" that there were "earth snails" at that time, "either with Ziwu Zhengzheng needles, or with Ziwu and Bingren needles." This earth compass is also a kind of water compass. At that time, yin and yang families used earth and earth to read Feng Shui. Diluo was also used when clearing land and deciding land lawsuits. According to records in "Pingzhou Ketan", "Xuanhe Envoy to Korea Illustrated Book", "Zhufan Zhi" and "Mengliang Lu", as late as the late Northern Song Dynasty, the compass had been used for navigation. In the Southern Song Dynasty, the "pin plate" was used navigation. This kind of dial also uses "floating needles", which has played a great role in the development of maritime transportation and economic and cultural exchanges between China and foreign countries.

2 Gunpowder

One of the four great inventions of ancient China. When ancient alchemists made medicines, they gradually discovered that the mixture of sulfur (S), flame salt (KN□) and charcoal (C) had the ability to burn and explode. In the late Tang Dynasty (904-906), gunpowder arrows began to appear in wars, and there were also records of "engines flying fire", that is, using trebuchets to throw gunpowder packets as incendiary weapons. In the Song Dynasty, Kaifeng Mansion in Tokyo (now Kaifeng, Henan Province) set up a large-scale siege operation, including a gunpowder production department. The book "Wu Jing Zong Yao" records three formulas of gunpowder, and the production of gunpowder has reached a considerable scale. Although the production technology was strictly kept secret, it was still introduced to the Liao Dynasty. Therefore, while large quantities of sulfur were imported from Japan, the export of sulfur and flame salt to the Liao Dynasty was strictly prohibited. During the reign of Emperor Shenzong Zhao Xu of the Song Dynasty, the border guards were equipped with a large number of weapons such as gunpowder bows and arrows, gunpowder artillery and arrows. During the reign of Emperor Daozong of the Liao Dynasty, he also had a "daily parade of artillery" in Jinfu, Nanjing (today's Beijing). During the Southern Song Dynasty, the navy was also equipped with thunderbolt cannons, artillery, rockets and other weapons. There were gunpowder weapons manufacturing industries in cities such as Jiankangfu (now Nanjing, Jiangsu Province) and Jianglingfu (now Jiangling, Hubei Province). Early gunpowder weapons had limited power and could not replace cold weapons. However, since the middle of the Southern Song Dynasty, the proportion of gunpowder weapons in weapons has increased significantly (see color picture) Rockets (models) tie the gunpowder barrel to the front of the arrow, and use the backward thrust generated when the gunpowder burns to drive the arrow forward. The Song Dynasty army One of the gunpowder weapons equipped). The gunpowder manufacturing technology of the Jin Dynasty originated from the Liao Dynasty. At the beginning of the Jin army's attack on the Song Dynasty, artillery was already used. Since then, gunpowder was used more and more frequently in the wars between the Song, Jin and Yuan Dynasties. When the Jin Dynasty fought against the Mongolian army, they used thunder, flying muskets and other firearms. In the Song Dynasty, iron artillery similar to modern artillery shells appeared, but they were still projected by trebuchets; they also invented the musket, which used giant bamboo as a tube to fire "zi nests", similar to later generations of guns, but did not yet use metal launch tubes. This was the limit of the progress of gunpowder weapons in the Liao, Song, and Jin dynasties, but it has determined the development direction of gunpowder weapons in later generations. In short, the Liao, Song, and Jin dynasties can be regarded as the foundation periods for human use of gunpowder. In the Yuan and Ming dynasties, tubular firearms made of copper and iron—guns and cannons—were discovered.

3 Papermaking

In the first year of Yuanxing of the Eastern Han Dynasty (105), Cai Lun reformed and promoted papermaking technology based on the previous papermaking technology. The new papermaking technology turned the old hemp paper, which was inconvenient to write on, into a good paper craft that has not changed its general structure to this day.

Before the emergence of Cai Lun's papermaking technology, in China, oracle bones were used in the Shang Dynasty, bronzes were used in the Western Zhou Dynasty, and bamboo slips, wooden slips, and silk were used as record materials in the Spring and Autumn Period. During the Han Dynasty, agriculture was developed, the economy was prosperous, national power was strong, and cultural undertakings were booming.

Bulky bamboo slips and expensive silk fabrics could no longer meet people's needs. It became a trend to seek new writing materials, and papermaking came into being.

According to the ancient hemp paper unearthed in Xinjiang, Shaanxi, Gansu and other places since the mid-20th century, experts confirmed it to be the sheet fiber material of hemp paper in the Western Han Dynasty, indicating that papermaking may have appeared before Cai Lun, and may have It is related to people's processing of hemp for textile use. However, no identifiable written characters have been found on these ancient hemp papers of the Western Han Dynasty. In addition, there are different interpretations of the laboratory analysis results. There is still a lot of controversy in the art circles about whether papermaking has appeared in the Western Han Dynasty. The record of Cai Lun's invention of papermaking in the "Book of the Later Han: Biography of Cai Lun" is the earliest record of papermaking that accurately records the time and person so far, and is widely recognized.

4 Printing

Since the advent of paper, with the development of economy and culture, more and more people are reading, and the demand for books has also increased greatly.

In the early years of the Jin Dynasty, the government had 29,945 volumes of books. During the Southern and Northern Dynasties, Emperor Yuan of Liang had more than 70,000 volumes of books in Jiangling, and the Jiaze Hall of the Sui Dynasty had 370,000 volumes of books. This is the highest collection record of the National Library in ancient my country.

In addition to government collections, there are also more and more private collections. For example, Mrs. Guo of the Jin Dynasty had 5,000 volumes of books; when Zhang Hua moved, he used thirty vehicles just to move the books.

Before the invention of printing, only the government and rich people like Mrs. Guo and Zhang Hua could have such a large collection of books. It was not easy for ordinary people to get one or two books, because the books at that time were all Codex. How much manpower it would take to copy so many manuscripts! If this situation does not change, how can we meet the needs of society?

History often has this situation: a scientific invention, as long as society urgently needs it and there are material conditions to produce it, then it will appear very quickly. Such was the advent of engraving and printing.

Before the advent of woodblock printing, seals and rubbings were widely used in society.

There are two types of seals: yang and yin. The characters engraved in yang are convex, while the characters engraved in yin are concave. "If you use a Yang script seal, it will be printed on the paper with black characters on a white background, which is very eye-catching. However, the seal is generally small, and the number of words printed is limited after all.

Inscriptions generally use Yin script, and the rubbings are White characters on a black background are not eye-catching enough. Moreover, the process of rubbing a stele is complicated and inconvenient for printing books. However, a big advantage of rubbing a stele is that it can cover many characters at a time.

What if the strengths and weaknesses are combined and the respective characteristics of the tablet and the seal are combined?

The working people of our country are using the two methods of rubbing the tablet and the seal. Inspired by , he invented block printing.

The method of block printing is as follows: saw the wood into pieces of wood, write the words to be printed on the thin paper, and stick it on the wood board. Then according to the strokes of each character, use a knife to carve the characters one by one so that the strokes of each character stand out on the board. When printing the book, use a knife first. The brush is dipped in ink and brushed on the carved board. Then, the self-made paper is covered on the board. Another clean brush is gently brushed on the back of the paper. The paper is taken off and a page of the book is printed. Okay. After printing each page, it is bound into a book. This printing method is to carve the words on the wooden board and then print it, so it is called "block printing". /p>