Baghdad BatteryThe Baghdad Battery is an artifact from between 250 BC and 250, discovered near Baghdad, with a structure similar to that of a modern, functioning [[Battery (electricity)| battery]].
In 1938, the German archaeologist Wilhelm Konig reported excavated this five-inch (or 13-cm)-long clay jar, in Khujut Rabu, near Baghdad, Iraq (though some reports say it was found in the collections of the National Museum of Iraq). The jar contained a copper cylinder, in turn covering and protecting an iron rod, isolated from the copper by asphalt. The artifact had been exposed to the weather and had suffered corrosion.
Konig's 1940 paper reporting the mechanism's resemblance to a battery was discounted by the scientific community and soon disregarded.
After the Second World War, Willard Gray demonstrated current production by a reconstruction of the inferred design when filled with grape juice. Subsequent tests found acidic residues in the original, analysed as an electrolytic solution, perhaps vinegar or wine.
Some contemporary researchers have renewed interest in interpreting this artifact, and suggested electroplating precious metals as a practical use for early batteries by Baghdad Parthians. Artifacts from ancient Egyptian sites, similarly resembling batteries, or bearing traces consistent with precious-metal electroplating, may support that.