- international Projects
Monies, Markets and Finance in China and East Asia, 1600-1900: Local, Regional, National and International Dimensions
研究专题：Coin Production Technology During the Seventeenth and Eighteenth Centuries in China: Metallurgical Analyses, Industrial Archaeology, and Documentary Evidence
专家：苏荣誉Prof. Su Rongyu (History of Science, Chinese Academy of Sciences)
In imperial China, the minting of coins was a government monopoly industry. As coins served as medium of exchange in economic transactions and as means for storing wealth, cash production directly affected many areas of economic life, including finance, prices, banking and credit, as well as the exchange with unminted silver that had become the main currency since about the fourteenth century. Coin production was a large-scale industry which involved the supply of raw materials, mining and transportation, management and manufacture, including the management of an at times unruly labor force, distribution of the finished product, counterfeiting, and a series of technological problems.
Within the scope of the proposed research group "Money and Finance in China, 1600-1900" our research will focus on coin production technology in the seventeenth and eighteenth centuries.
This field covers many aspects, such as mining, ore processing, smelting, metal alloying, coin casting, and finishing processes such as filing and polishing. Almost none of these steps in the production process of coins have been studied in detail, and some have not even been treated comprehensively. This project, therefore, will concentrate on the four production steps:
1. Copper and zinc smelting
From the sixteenth century onwards, Chinese coins consisted of brass, an alloy of copper and zinc. We will study the copper and zinc smelting technology on the basis of historical documents and investigations of traditional smelting processes that are quite close to the techniques used during the Qing period. As recently as twenty years ago, such traditional smelting techniques were still being used to produce zinc and copper. Combining an analysis of historical documents and on-site investigation, we will be able to examine technical aspects of copper and zinc smelting in the late imperial period with considerable precision.
During the Qing period, most of the metals used for minting came from Southwestern China, i.e. the provinces of Yunnan and Guizhou. According to investigations undertaken by this institute twenty years ago, huge remains of metal mining and smelting were then still in existence. For this project, industrial archaeological work on the known sites will be undertaken. These explorations will provide detailed information on smelting operations, including the organization of production, ore processing, the structure of the furnaces, and perhaps even of labor conditions.
2. Coin casting
Up to the late nineteenth century, all Chinese coins were cast, in adherence to the technological tradition that went back to the Chinese bronze age. For the large-style casting of coins, founding technology and organization were particularly important. Both depended not only on the implementation of the emperors' instructions, but also on the efficiency of the economic system. Quality control and counterfeiting were severe and continuous problems. In order to put together a better picture of casting technology and organization, we will carry out a detailed analysis of coin founding techniques and calculate technological parameters based on the study of archival documents. In the case of the metropolitan mints, regulations and precedents have survived, and these materials will be helpful in solving our questions.
The materials for coin casting were two main metals, namely copper and zinc, and two additional metals, namely lead and tin. The prices of these four different metals differed considerably, with copper being the most expensive. For this reason, mint workers tended to use more zinc or lead, while reducing the copper content in order to obtain an additional income by selling some of the copper clandestinely. Counterfeit coins always contained a relatively high proportion of the cheaper metals. Although the central government repeatedly issued strict regulations for the proportions of the alloy, profit-seeking behaviour meant that proportions were often changed arbitrarily by the mints.
With the help of special marks on each coin, we can determine the mint in which a specific coin was cast. By then analysing the chemical components of the coins, we will be able to evaluate the quality of the coinage of individual mints. At the same time, price studies will provide us with the information needed to assess the extent of costs saved and how high the profits were that mint workers or their supervising officials obtained through their fraud. Thus, some educated guesses can be made about profits derived from counterfeiting.
While mint metals were mostly procured from Southwestern China through the eighteenth and nineteenth centuries, in the late seventeenth century, copper was imported from Japan. In addition, large amounts of bronze and brass utensils were melted down for coinage.
Lead isotope studies, a fingerprint of the source of some metals, will be used to distinguish the provenience of the metals used in a certain number of mints. The results of this laboratory work will help us in establishing the metal supply system of these mints.
Structure of the project
The project outlined above is laid out for four years. The scale and depth of the investigations largely depends on the amount of source material that we will be able to acquire. In early summer 2005, Mr. Wang Xianguo, an M.A. candidate of my institute, will start work on the coin alloys. A doctoral candidate at the Chinese University of Science and Technology in Hefei will undertake the research on smelting technology. In addition, we expect three or more postgraduate students to join this project with work on more specific issues within the next couple of years.Professor Zhou Weirong, a specialist in metallurgy and vice-director of the Chinese Numismatic Museum in Beijing, intends to join the project to study aspects of zinc smelting and coin alloys. I myself will concentrate on the founding technology used for coin production.