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Author: Admin | 2025-04-28
Chemical powders by heating and transmuting copper by projection called their methods "Tanyang techniques".[36]The late Ming and Qing literature have very little information about paktong. However, it is first mentioned specifically by name in the Thien Kung Khai Wu of circa 1637:"When lu kan shih (zinc carbonate, calamine) or wo chhein (zinc metal) is mixed and combined with chih thung (copper), one gets 'yellow bronze' (ordinary brass). When phi shang and other arsenic substances are heated with it, one gets 'white bronze' or white copper: pai thong. When alum and niter and other chemicals are mixed together one gets ching thung: green bronze."[36]Ko Hung stated in 300 AD: "The Tanyang copper was created by throwing a mercuric elixir into Tanyang copper and heated- gold will be formed." However, the Pha Phu Tsu and the Shen I Ching describing a statue in the Western provinces as being of silver, tin, lead and Tanyang copper – which looked like gold, and could be forged for plating and inlaying vessels and swords.[36]Joseph Needham et al. argue that cupronickel was at least known as a unique alloy by the Chinese during the reign of Liu An in 120 BC in Yunnan. Moreover, the Yunnanese State of Tien was founded in 334 BC as a colony of the Chu. Most likely, modern paktong was unknown to Chinese of the day – but the naturally occurring Yunnan ore cupronickel alloy was likely a valuable internal trade commodity.[36]Greco-Bactrian coinage[edit]A Cupro-nickel coin of king Euthydemus II, c. 185–180
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