I thought Koenig was in charge of the Baghdad museum and he was examining other vases(not official "batteries") finding the evidence of electroplating. These were not necessarily batteries, but "electroplated" vases dating to Sumerian times. Conclusion, the Batteries are inherited technology from earlier times(yes Sumerian or earlier).
Electroplating is not a technology that was present in Sumeria. They did, however, have some gilding processes that were chemical in nature, such as electrodeless deposition of copper on iron which is done by use of a copper sulfate solution -no outside electricity involved (though, if my chemistry is still with me, there is an electro-chemical reaction due to the base metal's ions).
Not only is the process of electroplating complex, but it wasn't likely to have been discovered by accident either. And the discovery would have necessitated that there existed an understanding of electricity enough that the metallurgist could have known to apply current to a solution to create an affinity between the two metals. Also, it would have required a method of dissolving a metal in an electrolyte solution. The Sumerians were still figuring out the limits of bronze and hadn't yet figured out iron. So it isn't likely that they accidentally discovered electroplating and there exists no evidence to suggest that it occurred.
But back to the 1st century CE: this was the time of the Parthian Empire and the vessels in question were found in, what was then, Parthia, which extended down into Mesopotamia.
There is a very interesting hypothesis that the vessels weren't galvanic cells after all -admittedly, they *do* resemble galvanic cells, but this is, perhaps, a good example of looking at the past through the lens of the present. We can dismiss the electroplating possibility for a couple of reasons: the process wasn't invented until Faraday in the 18th cent. CE if memory serves correct); experimental archaeology conducted on replicas of the vessels as cells showed that about 0.5 v of current could be generated which could sustain itself for only a short time (Al-Haik 1964); empirical testing shows that it takes 1.1 days to electroplate 1 g of silver at 1 mW which is grossly inefficient.
So that raises the question again (since König's is dismissed): what was the purpose of such a strange looking configuration of a jar. Two possibilities, both very plausible, remain: 1) storage of papryii 2) the tools of a magician
The second is one that I find fascinating. Keyser (1993) reviewed the literature and examined the jars and began with the research hypothesis that they were medicinal in nature. He noticed that in antiquity it was common practice at the turn of the millennium to use electric eels as an analgesic to ease the pain of gout and headache, specifically the
torpedo ocellata. This was common practice in the coastal regions of the Aegean and the Mediterranean, but electric eel species don't exist in the Persian Gulf or Tigris/Euphrates waters. If the magicians new of the practice in the Med, they may have developed similar methods that don't require electric fish.
It could have been that someone, quite accidentally, discovered that by dipping a bronze spoon in vinegar contained by an iron bowl (or vice versa), they may have recognized the tingling sensation.
Then there must be examples of these that still have papyrus inside them, or some kind of remains. At least the idea of a place to keep scrolls seems somewhat plausible. What kind of containers has papyrus been found in?
There are many examples (Waterman 1931; Connan et al 1999) and papyrus has been found in all manner of ceramic jars, since they allowed the owner to keep them safe from the elements (water and written papyrii are not a good mix). Moreover, Papyrus was first used in Parthia as a writing material at around the time that the vessels are dated (1st century CE). And the bitumen, often described as "asphalt" in mentions of the "Baghdad Battery," was used frequently to waterproof and seal just about everything, including jars (Connan et al 1999).
To cut this short, I'll conclude by saying that the so-called "Baghdad Battery" is a mystery, but not for the reasons that mystery-mongers and significance-junkies call attention to. There is no evidence for a secret advanced society but, rather, just a plain mystery of the true nature of the artifacts. There have been many discovered that are similar, some in what appear to be a magician's house (Wateman 1931). They could be storage jars for papyrii or containers for magicians who were commonly referred to for all manner of healing throughout the Near East from the Bronze Age through nearly the Ottoman Empire.
References:
Al-Haik, A. (1964). The Rabbou'a Galvanic Cell,
Sumer 20, pp. 103-4.
Connan, J. ; et al (1999). Use and Trade of Bitumen in Antiquity and Prehistory: Molecular Archaeology Reveals Secrets of Past Civilizations [and Discussion].
Philosophical Transactions: Biological Sciences, Vol. 354, No. 1379, Molecular Information and Prehistory. , pp. 33-50.
Keyser, Paul T. (1993). The Purpose of Parthian Galvanic Cells: the First Century A.D. Electric Battery Used for Analgesia.
Journal of Near East Studies, 52(2), 81-82.
Kraeling, Carl H. (1952). A Dead Sea Scroll Jar.
Oriental Institute Bulletin of the American Schools of Oriental Research, 125, pp. 1, 5-7.
Waterman, Leroy (1931).
Preliminary Report upon the E.xcavations at Tel Umar. Ann Arbor; vol. 1.