In Silver by Fire, Silver by Mercury: A Chemical History of Silver Refining in New Spain and Mexico, 16th to 19th Centuries, Saul Guerrero combines historical research with geology and chemistry to refute the current prevailing narrative of a primitive effort dominated by mercury and its copious emissions to the air. Based on quantitative historical data, visual records and geochemical fundamentals, Guerrero analyses the chemical and economic reasons why two refining processes had to share production, creating along the way major innovations in the chemical recipes, milling equipment, mercury recycling practice, and industrial architecture and operations. Their main environmental impact was lead fume and the depletion of woodlands from smelting, and the transformation of mercury into calomel during the patio process.
Saul Guerrero is Visiting Professor of the Universidad Metropolitana, Caracas, Venezuela. He has a Ph.D. in Polymer Science from Bristol University (1980), and a Ph.D. in History from McGill University (2015). He has published articles on polymer science, oil energy policy and history.
General Series Editor’s Preface Acknowledgements List of Illustrations Guide to the text
1 The genesis and nature of silver ores Why Spain? To have and have not Old World silver ores New World silver ores A red herring The other chemical keys The immoveable object and the unstoppable force The table is set
2 The dry refining process: smelting of silver ores Deceitful mercury Smelting of silver ores: the human context The chemistry of smelting and the nature of the ore The architecture of smelting in New Spain The infrastructure of smelting in New Spain Plata de fuego (silver by fire)
3 The dry refining process: its impact on the environment Lead: the nature of its consumption Lead: the directionality of its loss Lead: its source Charcoal and the scale of depletion of woodland The local environmental impact of smelting A straightforward decision
4 The wet refining process: the chemistry of the patio process Plus ça change The alchemy of Mercury The gold connection The complex mechanism of a mercury-based refining process The correspondencia: the key to the fate of mercury The loss of calomel The stages in the use of mercury to refine gold and silver ores The twists in the trail Mercury-based refining of silver ores: the human factor Plata de azogue (silver by mercury)
5 The physical infrastructure of the patio process The patio process The architecture of the patio process The environmental impact vectors of the patio process A unique industrial effort
6 The Hacienda Santa María de Regla The nineteenth century The Adventurers in the Mines of Real del Monte The Hacienda de Regla Main process areas The mass balance of the silver refining processes at Regla, 1872 to 1888
7 The patio process and smelting at Regla The keys to an efficient patio process at Regla The challenges of the smelting process at Regla The efficiency of extracting silver at Regla The labour force at Regla The mass balance for the patio process at Regla The mass balance for smelting at Regla The environmental loss vectors in the period 1872 to 1888 A snapshot of a refining hacienda
8 The economies of refining silver Roads to riches Refining costs in New Spain, as reported The refining costs at Regla The false positives of the patio process Silver in the context of other commodity trades The bottom line
9 The environmental impact of silver refining: a shift of paradigm The base line An estimate of the breakdown of silver production by refining process by Caja Aggregate totals for New Spain Aggregate totals for Mexico, 1820 to 1900 Environmental impact vectors, sixteenth to nineteenth century What did they know and when did they know it? Was mercury the indispensable key to silver in the New World?
Appendix A: The accounting books of Regla Appendix B: Sensitivity matrix for refining costs Appendix C: Estimates of silver production by Caja and refining process, including balance of mercury consumption and physical losses Glossary of technical terms in Spanish Archival sources Bibliography Index
All interested in the history of the New World, Spain, Mexico, in global connections and transmission of knowledge in the Early Modern period, in environmental history, in metallurgy, and in geology.