China's progress from smelting arsenic brass to smelting arsenic white copper was about in the Eastern Jin Dynasty. According to our search, the earliest records of arsenic and copper can be found in The Secret of Immortality. The existing alchemy works in this department are noted by later generations, saying that it was "the biography of Taibai Mountain, collected by the assistant minister of Huangmen in the later Zhao Dynasty, and corrected by the microscope of Song and Chen", so the manuscript of this book should be written in the post-Zhao period from the second year of Xianhe in the Eastern Jin Dynasty to the seventh year of Yonghe (327 ~ 35 1) at the latest. Its text about arsenic and copper is as follows. Fourth, to put it bluntly: four-two salt sands, four-two realgar, four-two orpiment, four-two saltpeter, four-two dried alum, four-two mountain ze and four-two green salt, each with its own system. The powder on the right is as fine as powder, which is mixed with camphor willow root, salt, wine and vinegar to make one liter. Use a crucible, fill Yunnan copper with four taels, put it into a furnace, cover it with a fan box and melt it. Add two dollars of Salsa, stir well, add two ounces of the first medicine and one ounce of Yamazawa, then destroy, mix, repair and hold the fire. Green as (it should be "poured in") slide pool (it should be "Huachi") cools down and becomes a treasure. Any soft use.