In 1936, while excavating ruins of a 2000-year-old village near Baghdad, workers discovered mysterious small vase. A 6-inch-high pot of bright yellow clay dating back two millennia contained a cylinder of sheet-copper 5 inches by 1.5 inches. The edge of the copper cylinder was soldered with a 60-40 lead-tin alloy comparable to today’s solder. The bottom of the cylinder was capped with a crimped-in copper disk and sealed with bitumen or asphalt. Another insulating layer of asphalt sealed the top and also held in place an iron rod suspended into the center of the copper cylinder. The rod showed evidence of having been corroded with an acidic agent.
German archaeologist , Wilhelm König, examined the object and came to a surprising conclusion that the clay pot was nothing less than an ancient electric battery.
The ancient battery in the Baghdad Museum, as well as those others which were unearthed in Iraq, are all dated from the Parthian occupation between 248 BCE and 226 CE. However, Dr. Konig also found copper vases plated with silver in the Baghdad Museum, excavated from Sumerian sites in southern Iraq, dating back to at least 2500 BCE. When the vases were lightly tapped, a blue patina or film separated from the surface, which is characteristic of silver electroplated onto copper base. It would appear then that the Parthians inherited their batteries from one of the earliest known civilizations.
In 1940, Willard F.M. Gray, an engineer at the General Electric High Voltage Laboratory in Pittsfield, Massachusetts, read of Konig’s theory. Using drawings and details supplied by German rocket scientist Willy Ley, Gray made a replica of the battery. Using copper sulfate solution, it generated about half a volt of electricity.
In 1970s, German Egyptologist, Arne Eggebrecht built a replica of the Baghdad battery and filled it with freshly pressed grape juice, as he speculated the ancients might have done. The replica generated 0.87V. He used current from the battery to electroplate a silver statuette with gold.
This experiment proved that electric batteries were used some 1,800 years before their modern invention by Alessandro Volta in 1799. It also seems that the use of similar batteries can be safely placed into ancient Egypt, where several objects with traces of electroplated precious metals have been found at different locations. There are several anomalous finds from other regions, which suggests use of electricity on a grander scale.