Empires of Copper: British and American Global Trade, Chilean Copper, and the Transformation of the Chinese Monetary System (1736-1850)

My dissertation traces the crises and transformation of mid-19^th-century Qing China’s currency and economy by contextualizing them within Anglo-American trade, globalization, metallurgical technology, and the political economy of the Qing Empire. This project is inherently interdisciplinary and transnational, integrating history, economics, and chemistry.

The Qing Empire’s dual monetary system—silver for large transactions, long-distance trade, and taxation, copper cash for daily transactions and salary payments—underwent a profound disruption in the early 19^th century. Between 1820 and 1850, the silver price of copper cash plunged by 75%, shrinking state fiscal revenue by over 40% and sharply increasing the tax burden on households who earned wages in copper but paid taxes in silver. This destabilization led to the Daoguang Depression (1820–1850) and the ensuing Taiping Rebellion (1853–1864) – the deadliest civil war in imperial Chinese history (perhaps even in world history), claiming at least 20 million lives.

Conventionally, the Daoguang Depression and Taiping Rebellion have been attributed to silver outflows driven by the British opium trade. My dissertation, however, shows that by 1830, China’s domestic silver stock was far larger than historians have recognized, and silver lost to opium was no greater than the silver remitted to Inner Asia via Xinjiang for military expenditures between 1820 and 1850. The opium-silver outflow thesis, therefore, cannot explain the collapse of mid-19^th-century China’s economy and society.

Drawing on archival research conducted in Chinese, Spanish, and English across four continents (Mainland China, Chile, the United States, Britain, and Taiwan), my dissertation argues that China’s economic and social crises were instead triggered by a collapse in the copper-silver ratio, driven by two interrelated forces: an influx of Latin American copper through British and American trade networks, and Qing-state-sponsored debasement of the copper currency. Between 1820 and 1860, British and American firms flooded China with low-cost, high-purity Chilean copper that undermined the imperial mint system and eroded state fiscal capacity. This inflow lowered copper’s relative metallic value in East Asia and widened the monetary divergence between copper cash and silver. Besides, cheap, pure Chilean copper contributed to the decline of China’s domestic copper production in Yunnan.

My dissertation is also notable for employing natural science methods–specially, chemical analysis of Asian coins–to complement social sciences and humanities. Using inductively coupled plasma optical emission spectrometry (ICP-OES), I measured the elemental composition—copper, zinc, lead, iron, and tin—of 160 copper coins, including official Qianlong, Jiaqing, and Daoguang issues, alongside Japanese, Vietnamese, and counterfeit specimens. The metallurgical evidence exposes systematic, state-sanctioned debasement: Daoguang official coins were at least 10% lighter than Qianlong ones, and provincial mints even produced "official forgeries" weighing merely 30% of the standard weight. Such institutional corrosion invited rampant private counterfeiting, further degraded coin quality and generated mounting conflict over payment, as Qing legal cases demonstrate. As public trust in copper cash collapsed, demand for silver intensified.

Crucially, local governments faced mounting fiscal pressures during the Daoguang era. They received tax revenues in silver but spent largely in copper cash (such as payment for soldiers and public works). This structural asymmetry offered them little incentive to police inferior or counterfeit coinage; indeed, a depreciating copper cash effectively benefited their budgets. The resulting tension between local and central priorities thus further destabilized an already fragile copper currency market.

Compounding this domestic breakdown with massive inflow of Chilean copper, the collapse of the Daoguang copper currency system was thus not a symptom of silver drain but a decisive driver of mid-19^th-century monetary crisis. By reframing the Daoguang Depression and the Taiping Rebellion through global and Qing political economy, metallurgical technology, and monetary governance, my work redefines 19^th-century globalization as a process of recreating monetary system, fiscal institution, and everyday economic life.