Acupuncture: Acupuncture, the traditional Chinese medicinal practice of inserting needles into specific points of the body for therapeutic purposes and relieving pain, was first mentioned in the Huangdi Neijing compiled from the 3rd to 2nd centuries BC (Warring States period to Han Dynasty). The oldest known acupuncture sticks made of gold, found in the tomb of Liu Sheng (d. 113 BC), date to the Western Han (203 BC – 9 AD); the oldest known stone-carved depiction of acupuncture was made during the Eastern Han (25–220 AD); the oldest known bronze statue of an acupuncture mannequin dates to 1027 during the Song Dynasty (960–1279). Armillary sphere, hydraulic-powered: Hipparchus (c. 190 – c. 120 BC) credited the Ancient Greek mathematician, geographer, astronomer, and poet Eratosthenes (276–194 BC) as the first to invent the armillary sphere representing the celestial sphere. However, the Chinese astronomer Geng Shouchang of the Han Dynasty (202 BC – 220 AD) invented it separately in China in 52 BC, while the Han dynasty polymath Zhang Heng (78–139 AD) was the first to apply motive power to the rotating armillary sphere by a set of complex gears rotated by a waterwheel which in turn was powered by the constant pressure head of an inflow clepsydra clock, the latter of which he improved with an extra compensating tank between the reservoir and the inflow vessel. B Banknote: Paper currency was first developed in China. Its roots were in merchant receipts of deposit during the Tang Dynasty (618–907), as merchants and wholesalers desired to avoid the heavy bulk of copper coinage in large commercial transactions. During the Song Dynasty (960–1279), the central government adopted this system for their monopolized salt industry, but a gradual reduction in copper production—due to closed mines and an enormous outflow of Song-minted copper currency into the Japanese, Southeast Asian, Western Xia and Liao Dynasty economies—encouraged the Song government in the early 12th century to issue government-printed paper currency alongside copper to ease the demand on their state mints and debase the value of copper. In the early 11th century, the Song Dynasty government authorised sixteen private banks to issue notes of exchange in Sichuan, but in 1023 the government commandeered this enterprise and set up an agency to supervise the manufacture of banknotes there. The earliest paper currency was limited to certain regions and could not be used outside specified bounds, but once paper was securely backed