The Baghdad Battery

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 Konig, 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 Volatage 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.


The Riddle of "Baghdad's batteries"

Arran Frood investigates what could have been the very first batteries and how these important archaeological and technological artefacts are now at risk from the impending war in Iraq.




Biblical clues

It was in 1938, while working in Khujut Rabu, just outside Baghdad in modern day Iraq, that German archaeologist Wilhelm Konig unearthed a five-inch-long (13 cm) clay jar containing a copper cylinder that encased an iron rod.

The vessel showed signs of corrosion, and early tests revealed that an acidic agent, such as vinegar or wine had been present.In the early 1900s, many European archaeologists were excavating ancient Mesopotamian sites, looking for evidence of Biblical tales like the Tree of Knowledge and Noah's flood.
Konig did not waste his time finding alternative explanations for his discovery. To him, it had to have been a battery.
Though this was hard to explain, and did not sit comfortably with the religious ideology of the time, he published his conclusions. But soon the world was at war, and his discovery was forgotten.


Possible uses

Some have suggested the batteries may have been used medicinally.
The ancient Greeks wrote of the pain killing effect of electric fish when applied to the soles of the feet.

The Chinese had developed acupuncture by this time, and still use acupuncture combined with an electric current. This may explain the presence of needle-like objects found with some of the batteries.
But this tiny voltage would surely have been ineffective against real pain, considering the well-recorded use of other painkillers in the ancient world like cannabis, opium and wine.
Other scientists believe the batteries were used for electroplating - transferring a thin layer of metal on to another metal surface - a technique still used today and a common classroom experiment.
This idea is appealing because at its core lies the mother of many inventions: money.
In the making of jewellery, for example, a layer of gold or silver is often applied to enhance its beauty in a process called gilding.