The Four Great Inventions

China's long history has seen some extremely important inventions emerge, most noticeably gunpowder, paper making, printing and the compass, which, in the words of Roger Bacon, changed the whole appearance and status of things in the world.
China was the first country in the world to make proper paper. Paper made during the Western Han Dynasty (202 BC-16 AD) has been found in Gansu Province, Xi'an and other places in Shaanxi Province as well as Xinjiang. A further development of paper is credited to Cai Lun of the Eastern Han (25-220). He used plant fiber such as tree bark, bits of rope, rags and worn-out fishing nets as raw materials. In 105, Cai presented the first batch of paper made under his supervision to the Han emperor, who was so delighted that he named the material "Marquis Cai's paper". Eastern Han Dynasty paper found in Wuwei, Gansu, in 1974 carried words which were still clearly decipherable. Thin, soft, and with a smooth finish and tight texture, this paper is the most refined and oldest paper discovered to date.
Before paper was invented, the ancient Chinese carved characters on pottery, animal bones and stones, cast them on bronzes, or wrote them on bamboo or wooden strips and silk fabric. These materials, however, were either too heavy or two expensive for widespread use. The invention and use of paper brought about a revolution in writing materials, paving the way for the invention of printing technology in the years to come.
The invention of gunpowder was no doubt one of the most significant achievements of the Middle Ages in China. The correct prescription for making gunpowder with nitre, sulphur and carbon was probably discovered in the ninth century. In fact, in his book, Ge Hong in the third century records the procedures for making a kind of mixture that could be ignited. After the Tang Dynasty (618-907), things took a much faster course as gunpowder was already used in simple hand-grenades which were thrown by a catapult. In 1126, Li Gang, a local official, recorded how he ordered the defenders of the city of Kaifeng to "fire cannons" at the invading Nuzhen tribal people, inflicting heavy casualties on the invaders.
The first prescription for gunpowder appeared in 1044, much earlier than the earliest (1265) gunpowder-making instructions recorded in Europe. By the Song Dynasty (960-1126), gunpowder was in extensive use. Weapons made with it included rifles and rockets. The Song army also used a kind of flame thrower which involved packing gunpowder into bamboo tubes. The earliest picture of a European cannon shows that it bears a striking similarity to Chinese cannon of 1128.
About 1230, the Song army had cannon powerful enough to breach city walls.
A bronze Chinese cannon cast in 1332 is the oldest one in the world extant today. Many bronze and iron cannons have been unearthed in China, most of them bearing inscriptions dating them to between 1280 and 1380.
On the basis of printing using carved blocks in the Tang Dynasty, Bi Sheng of the Northern Song Dynasty invented movable type printing in the 1040s, which ushered in a major revolution in the history of printing.
Bi's printing consisted of four processes: making the types, composing the text, printing and retrieving the movable types. According to Dream Stream Essays, Bi Sheng carved individual characters on squares of sticky clay, then baked them make clay type pieces. When composing a text, he put a large iron frame on a piece of iron board and arranged the words within the frame. While one plate was being printed, another plate could be composed. After printing, the movable types were taken away and stored for future use. Movable type printing has a very important position in the history of printing, for all later printing methods such as wooden type, copper type and lead type printing invariably developed on the basis of movable clay types. Bi Sheng created movable type printing more than four hundred years earlier than it was invented in Europe.
According to ancient records, natural magnets were employed in China as direction-finding devices. This led to the first compass, called a sinan (south-pointing ladle) during the Warring States Period. In the Han Dynasty compasses consisted of a bronze on which 24 directions were carved and a rod made from a natural magnet. Such devices were in use until the eighth century.
In the Song Dynasty, Shen Kuo described the floating compass, suspended in water, a technique which minimized the effect of motion on the instrument. This enabled the compass to be used for sea navigation for the first time. The invention of the compass promoted maritime undertakings, and its use soon spread to the Arab world, and thence to Europe.
China's four great ancient inventions made tremendous contributions to the world's economy and the culture of mankind. They were also important symbols of China's role as a great world civilization.