Baghdad battery

The Baghdad Battery or Parthian Battery is a set of three artifacts which were found together: a ceramic pot, a tube of one metal, and a rod of another. Although the Seleucia vessels do not have the outermost clay jar, they are otherwise almost identical.

Wilhelm König was an assistant at the National Museum of Iraq in the 1930s. In 1938 he authored a paper offering the hypothesis that they may have formed a galvanic cell, perhaps used for electroplating gold onto silver objects. This interpretation is generally rejected today.

While some researchers refer to the object as a battery, the origin and purpose of the object remains unclear. In March 2012, Professor Elizabeth Stone, of Stony Brook University, an expert on Iraqi archaeology, returning from the first archaeological expedition in Iraq after 20 years, stated that she does not know a single archaeologist who believed that these were batteries.

The artifacts consist of terracotta pots approximately 130 mm (5 in) tall (with a one-and-a-half-inch mouth) containing a cylinder made of a rolled copper sheet, which houses a single iron rod. At the top, the iron rod is isolated from the copper by bitumen, which plugs or stoppers, and both rod and cylinder fit snugly inside the opening of the jar. The copper cylinder is not watertight, so if the jar were filled with a liquid, this would surround the iron rod as well. The artifact had been exposed to the weather and had suffered corrosion.

König thought the objects might date to the Parthian period, between 250 BC and AD 224, but according to St John Simpson of the Near Eastern department of the British Museum, their original excavation and context were not well-recorded, and evidence for this date range is very weak. Furthermore, the style of the pottery is Sassanid (224-640).

...
Wikipedia