1、The compass
A compass is a simple instrument for judging directions. The predecessor is si nan. The main component is a magnetic needle mounted on a shaft that can rotate freely.
Under the action of the geomagnetic field, the magnetic needle can stay in the tangential direction of the magnetic meridian.
The North Pole of the magnetic needle points to the geographic North Pole, which can be used to identify directions.
Commonly used in navigation, geodesy, travel and military, etc. N for north, E for east, W for west, S for compass.
2、Paper-making
Papermaking is one of China's four great inventions and an outstanding invention in the history of human civilization. China was the first country in the world to raise silkworms and weave silk.
In ancient China, the silk cocoons of the working people and above were used to draw silk and weave silk. After finishing the floc, the bamboo mat will be left some residual floc.
When the number of drift floc more, bamboo mat on the residual floc will be accumulated into a layer of thin fiber, after drying off, can be used for writing.
This flocculant floating there aren't many by-products, and call it h 蹏 on ancient book or side effect. This shows that the origin of Chinese papermaking is closely related to silk floc.
3、Gunpowder
A black or brown explosive, mechanically mixed with potassium nitrate, charcoal, and sulfur, initially in powder form and later in granules of different sizes, for different purposes,
until the use of smokeless gunpowder, has been used as the only military propellant.
4、The printing press
The earliest engraving found so far is a single page version of the douroni sutra in Indian Sanskrit, printed on linen paper, published between 650 and 670 years ago, and unearthed in a tang dynasty tomb near xi 'an in 1974.
In 1966, archaeologists in South Korea discovered a miniature version of the doloni buddhist sutra, which contained the text of the zuren script issued by empress wu zetian of the tang dynasty (C. 690-705).
Scholars determined that the sutra did not date back to 704 and was later preserved in a stupa built during the unification of silla in 751.
However, the earliest known printed book of an average size was the diamond sutra published during the tang dynasty (618-907).
The scroll, which is 5.18 meters (17 feet) long and in scroll format, dates back to April 15 (868), the ninth lunar month of emperor yizong's reign.
The accounts of scholars Joseph Needham and Tsien tsuen-hsuin show that the calligraphy and carving techniques of the tang dynasty diamond sutra were far more advanced and sophisticated than the single-page Indian version of the doloni sutra,
which was printed earlier. In addition, the two oldest printed lunar calendar dates are 877 and 882, when they were discovered in dunhuang.