بطارية بغداد (Baghdad Battery)
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The Baghdad Battery or Parthian Battery is a set of three artifacts which were found together: a ceramic pot, a tube of copper, and a rod of iron. It was discovered in modern Khujut Rabu, Iraq, close to the metropolis of Ctesiphon, the capital of the Parthian (150 BC – 223 AD) and Sasanian (224–650 AD) empires of Persia, and it is believed to date from either of these periods.
Its origin and purpose remain unclear. It was hypothesized by some researchers that the object functioned as a galvanic cell, possibly used for electroplating, or some kind of electrotherapy, but there is no electroplated object known from this period. An alternative explanation is that it functioned as a storage vessel for sacred scrolls.
The artifacts consist of a terracotta pot 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, with 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.
German archeologist Wilhelm König thought the objects might date to the Parthian period, between 250 BC and AD 224. However, 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).[1][2]
Its origin and purpose remain unclear.[1] Wilhelm König was an assistant at the National Museum of Iraq in the 1930s. He had observed a number of very fine silver objects from ancient Iraq, plated with very thin layers of gold, and speculated that they were electroplated. In 1938 he authored a paper[3][4] offering the hypothesis that they may have formed a galvanic cell, perhaps used for electroplating gold onto silver objects.[1] This interpretation is rejected by skeptics.[5][6]
Corrosion of the metal and tests both indicate that an acidic agent such as wine or vinegar was present in the jar.[1] This led to speculation that the liquid was used as an acidic electrolyte solution to generate an electric current from the difference between the electrode potentials of the copper and iron electrodes.[2]
