Thursday, March 19, 2009

Four Great Inventions of ancient China

The Four Great Inventions of ancient China are four inventions that are celebrated in Chinese culture for their historical significance and as signs of ancient China's advanced science and technology.

The Four Great Inventions are:

The Compass

The Compass

Diagram of a Ming dynasty mariner's compassMain article: Compass
The earliest reference to magnetism in Chinese literature is found in a 4th century BC book called Book of the Devil Valley Master (鬼谷子): "The lodestone makes iron come or it attracts it."

The earliest reference to a magnetic device used as a "direction finder" is in a Song Dynasty book dated to AD 1040-44. Here there is a description of an iron "south-pointing fish" floating in a bowl of water, aligning itself to the south. The device is recommended as a means of orientation "in the obscurity of the night."[9] However, the first suspended magnetic needle compass was written of by Shen Kuo in his book of AD 1088.

For most of Chinese history, the compass that remained in use was in the form of a magnetic needle floating in a bowl of water.[10] According to Needham, the Chinese in the Song Dynasty and continuing Yuan Dynasty did make use of a dry compass, although this type never became as widely used in China as the wet compass.

The dry compass used in China was a dry suspension compass, a wooden frame crafted in the shape of a turtle hung upside down by a board, with the loadstone sealed in by wax, and if rotated, the needle at the tail would always point in the northern cardinal direction.Although the 14th century European compass-card in box frame and dry pivot needle was adopted in China after its use was taken by Japanese pirates in the 16th century (who had in turn learned of it from Europeans), the Chinese design of the suspended dry compass persisted in use well into the 18th century.[12]


Handgun from the Yuan dynasty, circa 1300s.Main article: History of gunpowder
The prevailing academic consensus is that gunpowder was discovered in the 9th century by Chinese alchemists searching for an elixir of immortality.[13] By the time the Song Dynasty treatise, Wujing Zongyao (武经总要), was written by Zeng Gongliang and Yang Weide in AD 1044, the various Chinese formulas for gunpowder held levels of nitrate in the range of 27% to 50%.[14] By the end of the 12th century, Chinese formulas of gunpowder had a level of nitrate capable of bursting through cast iron metal containers, in the form of the earliest hollow, gunpowder-filled grenade bombs.[15]

In AD 1280, the bomb store of the large gunpowder arsenal at Weiyang accidentally caught fire, which produced such a massive explosion that a team of Chinese inspectors at the site a week later deduced that some 100 guards had been killed instantly, with wooden beams and pillars blown sky high and landing at a distance of over 10 li (~2 mi. or ~3.2 km) away from the explosion.[16]

By the time of Jiao Yu and his Huolongjing in the mid 14th century, the explosive potential of gunpowder was perfected, as the level of nitrate in gunpowder formulas had risen to a range of 12% to 91%,[14] with at least 6 different formulas in use that are considered to have maximum explosive potential for gunpowder.[14] By that time, the Chinese had discovered how to create explosive cannonballs by packing their hollow shells with this nitrate-enhanced gunpowder.[17]


Hemp wrapping paper, China, circa 100 BCMain article: Papermaking
Further information: Science and technology of the Han Dynasty
Papermaking has traditionally been traced to China about AD 105, when Cai Lun, an official attached to the Imperial court during the Han Dynasty (202 BC-AD 220), created a sheet of paper using mulberry and other bast fibres along with fishnets, old rags, and hemp waste.[18] However a recent archaeological discovery has been reported from near Dunhuang of paper with writing on it dating to 8 BC.[19]

While paper used for wrapping and padding was used in China since the 2nd century BC,[20] paper used as a writing medium only became widespread by the 3rd century.[21] By the 6th century in China, sheets of paper were beginning to be used for toilet paper as well.[22] During the Tang Dynasty (AD 618–907) paper was folded and sewn into square bags to preserve the flavor of tea.[20] The Song Dynasty (AD 960–1279) that followed was the first government on Earth to issue paper currency.

Main article: History of typography in East Asia
The Chinese invention of Woodblock printing, at some point before the first dated book in 868 (the Diamond Sutra), produced the world's first print culture. According to A. Hyatt Mayor, curator at the Metropolitan Museum of Art, "it was the Chinese who really discovered the means of communication that was to dominate until our age."[23] Woodblock printing was better suited to Chinese characters than movable type, which the Chinese also invented, but which did not replace woodblock printing. Western printing presses, although introduced in the 16th century, was not widely used in China until the 19th century. China, along with Korea, was one of the last countries to adopt them.[24]

The intricate frontispiece of the Diamond Sutra from Tang Dynasty China, AD 868 (British Museum)Woodblock printing for textiles, on the other hand, preceded text printing by centuries in all cultures, and is first found in China at around 220,[25] then Egypt in the 4th century,[26] and reached Europe by the 14th century or before, via the Islamic world, and by around 1400 was being used on paper for old master prints and playing cards.[27][28] In another analysis Hyatt Mayor states that "a little before 1400 Europeans had enough paper to begin making holy images and playing cards in woodcut. They need not have learned woodcut from the Chinese, because they had been using woodblocks for about 1,000 years to stamp designs on linen."[29]

Printing in China was further advanced by the 11th century, as it was written by the Song Dynasty scientist and statesman Shen Kuo (1031-1095) that the common artisan Bi Sheng (990-1051) invented ceramic movable type printing.[30] Then there were those such as Wang Zhen (fl. 1290-1333) and Hua Sui (1439-1513), the former of whom invented wooden movable type printing in China,[31] the latter of whom invented metal movable type printing in China.[32] Movable type printing was a tedious process if one were to assemble thousands of individual characters for the printing of simply one or a few books, but if used for printing thousands of books, the process was efficient and rapid enough to be successful and highly employed. Indeed, there were many cities in China where movable type printing, in wooden and metal form, was adopted by the enterprises of wealthy local families or large private industries. The Qing Dynasty court sponsored enormous printing projects using woodblock movable type printing during the 18th century. Although superseded by western printing techniques, woodblock movable type printing remains in use in isolated communities in China.[33]

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