when was gunpowder first discovered in ancient china
History of gunpowder Gunpowder is the first physical explosive. Before its discovery, many incendiary and burning devices had been used, including Greek fire. The discovery of gunpowder is attributed to experimentation in Chinese alchemy by Taoists in the pursuit of immortality, and is popularly listed as one of the "Four Great Inventions" of China. It was discovered during the late Tang dynasty (9th century) but the earliest record of a written formula appeared in the Song dynasty (11th century). Knowledge of gunpowder spread rapidly throughout the Old World possibly as a result of the Mongol conquests during the 13th century, with written formula for it appearing in the 1267 Opus Majus treatise by Roger Bacon and a 1280 treatise by Hasan al-Rammah. It was employed in warfare to some effect from at least the 12th century in weapons such as fire arrows, bombs, and the fire lance before the appearance of the gun. While the fire lance was eventually supplanted by the gun, other gunpowder weapons such as rockets and fire arrows continued to see use in China, Korea, India, and eventually Europe. Bombs too never ceased to develop and continued to progress into the modern day as grenades, mines, and other explosive implements. Gunpowder has also been used for non-military purposes such as fireworks for entertainment, or in explosives for mining and tunneling.
Small intestine Food from the stomach is allowed into the duodenum through the pylorus by a muscle called the pyloric sphincter.
Agent Orange Agent Orange was used in Korea in the late 1960s.[128]
History of the Great Wall of China One of the first mentions of a wall built against northern invaders is found in a poem, dated from the seventh century BC, recorded in the Classic of Poetry. The poem tells of a king, now identified as King Xuan (r.  827 – 782 BC) of the Western Zhou dynasty (1046 – 771 BC), who commanded General Nan Zhong (南仲) to build a wall in the northern regions to fend off the Xianyun.[22] The Xianyun, whose base of power was in the Ordos region, were regarded as part of the charioteering Rong tribes,[23] and their attacks aimed at the early Zhou capital region of Haojing were probably the reason for King Xuan's response.[22] Nan Zhong's campaign was recorded as a great victory. However, only a few years later in 771 BC another branch of the Rong people, the Quanrong, responded to a summons by the renegade Marquess of Shen by over-running the Zhou defences and laying waste to the capital. The cataclysmic event killed King Xuan's successor King You (795–771 BC), forced the court to move the capital east to Chengzhou (成周, later known as Luoyang) a year later, and thus ushered in the Eastern Zhou dynasty (770–256 BC). Most importantly, the fall of Western Zhou redistributed power to the states that had acknowledged Zhou's nominal rulership. The rule of the Eastern Zhou dynasty was marked by bloody interstate anarchy. With smaller states being annexed and larger states waging constant war upon one another, many rulers came to feel the need to erect walls to protect their borders. Of the earliest textual reference to such a wall was the State of Chu's wall of 656 BC, 1,400 metres (4,600 feet) of which were excavated in southern Henan province in the modern era. However the Chu border fortifications consisted of many individual mountain fortresses; they do not constitute to a lengthy, single wall. The State of Qi also had fortified borders up by the 7th century BC, and the extant portions in Shandong province had been christened the Great Wall of Qi. The State of Wei built two walls, the western one completed in 361 BC and the eastern in 356 BC, with the extant western wall found in Hancheng, Shaanxi.[24] Even non-Chinese peoples built walls, such as the Di state of Zhongshan and the Yiqu Rong, whose walls were intended to defend against the State of Qin.[25]