Baghdad Battery Guide, Meaning , Facts, Information and Description
The Baghdad Battery is the common name for a number of artefacts apparently discovered in the village of Khuyut Rabbou'a (near Baghdad, Iraq) in the 1936. These artefacts came to wider attention in 1938, when Wilhelm König, the German director of the National Museum of Iraq, found the objects in the museum's collections, and (in 1940, having returned to Berlin due to illness) published a paper speculating that they may have been galvanic cells, perhaps used for electroplating gold onto silver objects.
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2 Dating 3 Speculations on function 4 Controversy 5 See also 6 External links, references, resources 7 References |
Description
The artefacts consist of ~130 mm (~5 inch) long clay jars containing a copper cylinder made of a rolled up copper sheet, capped at the bottom, in turn covering and protecting an iron rod. The iron rods are isolated from the copper by asphalt plugs or stoppers, and the cylinders fairly neatly fit the necks of the jars, which bulge toward the middle. The copper cylinders are not watertight, so that if the jars were filled with a liquid, this would surround the iron rod as well. The artefacts had been exposed to the weather and had suffered corrosion, although fairly mild given the presence of an electrochemical couple (this tends to argue against a very ancient date).
Dating
König thought the objects might be Parthian (between 250 BC and 224 AD) because the village where they were excavated was Parthian. However according to Dr. St John Simpson of the Near Easternern department of the British Museum their original excavation and context were not well recorded (see stratigraphy), so evidence for this date range is very weak. Furthermore, the style of the pottery (see typology) is Sassanian (224-640 AD), so they are probably much more recent than König thought.
Most of the components of the objects are not particularly amenable to advanced dating methods. The ceramic pots could be analysed by thermoluminescence dating, but this has apparently not yet been done; in any case, it would only date the firing of the pots, which is not necessarily the same as when the complete artefact was assembled. Another possibility would be ion diffusion analysis, which could indicate how long the objects were buried.
Speculations on function
Electrical
Copper and iron form an electrochemical couple, so that in the presence of any electrolyte, an electric potential (voltage) will be produced. König had observed a number of very fine silver objects from ancient Iraq which were plated with very thin layers of gold, and speculated that they were electroplated using batteries of these "cells". After the Second World War, Willard Gray demonstrated current production by a reconstruction of the inferred battery design when filled with grape juice. However, even among those who believe the artefacts were in fact electrical devices, electroplating as a use is not well regarded today. The gilded objects which König thought might be electroplated are now universally believed to have been fire-gilded (with mercury), and reproduction experiments of electroplating by Dr. Arne Eggebrecht consumed "many" reproduction cells to achieve a plated layer just one micron thick. Other scientists noted that Dr. Eggebrecht used a more efficient, modern electrolyte; using vinegar the "battery" is even more feeble.
An alternative but still electrical explanation was offered by Paul Keyser. It was suggested that a priest or healer, using an iron spatula to compound a vinegar based potion in a copper vessel, may have felt an electrical tingle, and used the phenomenon either for electro-acupuncture, or to amaze supplicants by electrifying a metal statue.
Nonelectrical
Many archaeologists see the electrical experiments as embodying a key problem with experimental archaeology; such experiments can only show that something was physically possible, they say nothing about whether it actually occurred. Further, there are many difficulties with the interpretation of these artefacts as galvanic cells:
- the asphalt completely covers the copper cylinder, electrically insulating it, so no current can be drawn without modifying the design;
- there are no wires, conductors, or any other sort of electrical equipment associated with them;
- any such electrical phenomena seem to have gone completely unrecorded within their cultures, and then been completely forgotten, even though we have extensive records from both Parthian and Sassanian periods;
- an asphalt seal, being thermoplastic, is excellent for forming a hermetic seal for long term storage. It would be extremely inconvenient however for a galvanic cell, which would require frequent topping up of the electrolyte.
Some have claimed that these artefacts provide evidence of ancient knowledge of electricity, millennia before the conventional dates given for its discovery. However even if it is accepted that the "Baghdad batteries" were in fact electrical devices, this provides no evidence of any real knowledge of electrical phenomena. For example, it is well known that the Ancient Greeks were aware of electrostatic electrical phenomena produced by amber, but they regarded it as a mere curiosity or toy and developed no electrical theory or functional devices. For evidence of ancient Parthian knowledge of the ideas of electricity, we would have to see some evidence of its use, see it discussed in their writings, or see that their "batteries" were designed with a knowledge of electrical theory. As electrical generators, the "Baghdad batteries" would be extremely inefficient. This can be contrasted with the discoveries of a similar electrochemical couple by Luigi Galvani in the 1780s; less than 20 years later Alessandro Volta had developed enough theory to convert Galvani's simple experiment into the remarkably efficient and powerful voltaic pile, producing significant current at 30 volts. Within two or three more years Sir Humphry Davy was using voltaic piles that produced 1,000 volts and enough current to run an arc lamp.
Still more controversial is the suggestion that the existence of these artefacts indicates that the Ancient Egyptians could have used electric lighting in the construction of the Egyptian pyramids. This suggestion is met by many objections, including:
This is an Article on Baghdad Battery. Page Contains Information, Facts Details or Explanation Guide About Baghdad Battery Controversy
See also
External links, references, resources
References