<Li> Blast furnace: Although cast iron tools and weapons have been found in China dating to the 5th century BC, the earliest discovered Chinese blast furnaces, which produced pig iron that could be remelted and refined as cast iron in the cupola furnace, date to the 3rd and 2nd centuries BC, while the vast majority of early blast furnace sites discovered date to the Han Dynasty (202 BC--220 AD) period immediately following 117 BC with the establishment of state monopolies over the salt and iron industries during the reign of Emperor Wu of Han (r . 141--87 BC); most ironwork sites discovered dating before 117 BC acted merely as foundries which made castings for iron that had been smelted in blast furnaces elsewhere in remote areas far from population centres . </Li> <Li> Bombard weaponry: The oldest representation of a bombard can be found in the Chinese town of Ta - tsu . In 1985, the Canadian historian Robin Yates visited the Buddhist cave temples when he saw a sculpture on the wall depicting a demon holding a hand - held bombard . The muzzle seems to have a blast and flames coming from it which some believe is proof of some type of super gun . Yates examined the cave and believed the drawings dated back to the late 12th century . </Li> <Li> Bomb, cast iron: The first accounts of bombs made of cast iron shells packed with explosive gunpowder--as opposed to earlier types of casings--were written in the 13th century in China . The term was coined for this bomb (i.e. "thunder - crash bomb") during a Jin Dynasty (1115--1234) naval battle of 1231 against the Mongols . The History of Jin (compiled by 1345) states that in 1232, as the Mongol general Subutai (1176--1248) descended on the Jin stronghold of Kaifeng, the defenders had a "thunder - crash bomb" which "consisted of gunpowder put into an iron container...then when the fuse was lit (and the projectile shot off) there was a great explosion the noise whereof was like thunder, audible for more than a hundred li, and the vegetation was scorched and blasted by the heat over an area of more than half a mou . When hit, even iron armour was quite pierced through ." The Song Dynasty (960--1279) official Li Zengbo wrote in 1257 that arsenals should have several hundred thousand iron bomb shells available and that when he was in Jingzhou, about one to two thousand were produced each month for dispatch of ten to twenty thousand at a time to Xiangyang and Yingzhou . The significance of this, as British sinologist, scientist, and historian Joseph Needham states, is that a "high - nitrate gunpowder mixture had been reached at last, since nothing less would have burst the iron casing ." </Li> <Li> Borehole drilling: By at least the Han Dynasty (202 BC--220 AD), the Chinese used deep borehole drilling for mining and other projects; The British sinologist and historian Michael Loewe states that borehole sites could reach as deep as 600 m (2000 ft). K.S. Tom describes the drilling process: "The Chinese method of deep drilling was accomplished by a team of men jumping on and off a beam to impact the drilling bit while the boring tool was rotated by buffalo and oxen ." This was the same method used for extracting petroleum in California during the 1860s (i.e. "Kicking Her Down"). A Western Han Dynasty bronze foundry discovered in Xinglong, Hebei had nearby mining shafts which reached depths of 100 m (328 ft) with spacious mining areas; the shafts and rooms were complete with a timber frame, ladders and iron tools . By the first century BC, Chinese craftsmen cast iron drill bits and drillers were able to drill boreholes up to 4800 feet (1500 m) deep . By the eleventh century AD, the Chinese were able to drill boreholes up to 3000 feet in depth . Drilling for boreholes was time consuming and long . As the depth of the holes varied, the drilling of a single well could up to nearly one full decade . It wasn't up until the 19th century that Europe and the West would catch up and rival ancient Chinese borehole drilling technology . </Li>

Ancient chinese inventions and discoveries that shaped the world