The Baghdad Battery - iron & copper submerged in electrolytic solution - found near Khuyut Rabbou'a archaeological site in Iraq. Galvanic cells using oxidation-reduction to generate electron flow. Some jars contained rolled copper sheets alongside metals. Electricity produced was minuscule, no wiring found. What were they really for?
Proposed alternative function: galvanic cells used for precious metal extraction from mine runoff solutions
- Noble metals (gold, silver, copper) accumulate on cathode through electrochemical reduction
- Reactive metals (iron, nickel, magnesium) form sludge deposits at bottom of vessel
- Mercury used by Romans in amalgamation process to extract silver and gold from ore
- Lack of metal residue on cathodes explained by harvesting and salvage of accumulated precious metals
