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.
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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
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.
I don't think anyone can say for sure what they were used for,
but they may have been batteries because they do work Dr
Marjorie Senechal
War can destroy more than a people, an army or a leader. Culture,
tradition and history also lie in the firing line.
Iraq has a rich national heritage. The Garden of Eden and the Tower
of Babel are said to have been sited in this ancient land.
In any war, there is a chance that priceless treasures will be
lost forever, articles such as the "ancient battery" that
resides defenceless in the museum of Baghdad.
For this object suggests that the region, whose civilizations
gave us writing and the wheel, may also have invented electric cells
- two thousand years before such devices were well known.
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 KEY COMPONENTS
Batteries dated to around 200 BC Could have been used in gilding
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.
Scientific awareness
More than 60 years after their discovery, the batteries of
Baghdad - as there are perhaps a dozen of them - are shrouded in
myth.
"The batteries have always attracted interest as
curios," says Dr Paul Craddock, a metallurgy expert of the
ancient Near East from the British Museum.
"They are a one-off. As far as we know, nobody else has
found anything like these. They are odd things; they are one of
life's enigmas."
No two accounts of them are the same. Some say the batteries were
excavated, others that Konig found them in the basement of the
Baghdad Museum when he took over as director. There is no definite
figure on how many have been found, and their age is disputed.
Most sources date the batteries to around 200 BC - in the
Parthian era, circa 250 BC to AD 225. Skilled warriors, the
Parthians were not noted for their scientific achievements.
"Although this collection of objects is usually dated as
Parthian, the grounds for this are unclear," says Dr St John
Simpson, also from the department of the ancient Near East at the
British Museum.
"The pot itself is Sassanian. This discrepancy presumably
lies either in a misidentification of the age of the ceramic vessel,
or the site at which they were found."
Underlying principles
In the history of the Middle East, the Sassanian period (circa AD
225 - 640) marks the end of the ancient and the beginning of the
more scientific medieval era.
Though most archaeologists agree the devices were batteries,
there is much conjecture as to how they could have been discovered,
and what they were used for.
How could ancient Persian science have grasped the principles of
electricity and arrived at this knowledge?
Perhaps they did not. Many inventions are conceived before the
underlying principles are properly understood.
The Chinese invented gunpowder long before the principles of
combustion were deduced, and the rediscovery of old herbal medicines
is now a common occurrence.
You do not always have to understand why something works - just
that it does.
Enough zap
It is certain the Baghdad batteries could conduct an electric
current because many replicas have been made, including by students
of ancient history under the direction of Dr Marjorie Senechal,
professor of the history of science and technology, Smith College,
US.
"I don't think anyone can say for sure what they were used
for, but they may have been batteries because they do work,"
she says. Replicas can produce voltages from 0.8 to nearly two
volts.
Making an electric current requires two metals with different
electro potentials and an ion carrying solution, known as an
electrolyte, to ferry the electrons between them.
Connected in series, a set of batteries could theoretically produce
a much higher voltage, though no wires have ever been found that
would prove this had been the case.
"It's a pity we have not found any wires," says Dr
Craddock. "It means our interpretation of them could be
completely wrong."
But he is sure the objects are batteries and that there could be
more of them to discover. "Other examples may exist that lie in
museums elsewhere unrecognised".
He says this is especially possible if any items are missing, as
the objects only look like batteries when all the pieces are in
place.
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.
Grape electrolyte
Two main techniques of gilding were used at the time and are
still in use today: hammering the precious metal into thin strips
using brute force, or mixing it with a mercury base which is then
pasted over the article.
These techniques are effective, but wasteful compared with the
addition of a small but consistent layer of metal by
electro-deposition. The ability to mysteriously electroplate gold or
silver on to such objects would not only save precious resources and
money, but could also win you important friends at court.
Let's hope the world manages to resolve its present problems
so people can go and see them. Dr Paul
Craddock
A palace, kingdom, or even the sultan's daughter may have been the
reward for such knowledge - and motivation to keep it secret.
Testing this idea in the late seventies, Dr Arne Eggebrecht, then
director of Roemer and Pelizaeus Museum in Hildesheim, connected
many replica Baghdad batteries together using grape juice as an
electrolyte, and claimed to have deposited a thin layer of silver on
to another surface, just one ten thousandth of a millimetre thick.
Other researchers though, have disputed these results and have
been unable to replicate them.
"There does not exist any written documentation of the
experiments which took place here in 1978," says Dr Bettina
Schmitz, currently a researcher based at the same Roemer and
Pelizaeus Museum.
"The experiments weren't even documented by photos, which
really is a pity," she says. "I have searched through the
archives of this museum and I talked to everyone involved in 1978
with no results."
Tingling idols
Although a larger voltage can be obtained by connecting more than
one battery together, it is the ampage which is the real limiting
factor, and many doubt whether a high enough power could ever have
been obtained, even from tens of Baghdad batteries.
One serious flaw with the electroplating hypothesis is the lack
of items from this place and time that have been treated in this
way.
"The examples we see from this region and era are
conventional gild plating and mercury gilding," says Dr
Craddock. "There's never been any untouchable evidence to
support the electroplating theory."
He suggests a cluster of the batteries, connected in parallel,
may have been hidden inside a metal statue or idol.
He thinks that anyone touching this statue may have received a
tiny but noticeable electric shock, something akin to the static
discharge that can infect offices, equipment and children's parties.
"I have always suspected you would get tricks done in the
temple," says Dr Craddock. "The statue of a god could be
wired up and then the priest would ask you questions.
"If you gave the wrong answer, you'd touch the statue and
would get a minor shock along with perhaps a small mysterious blue
flash of light. Get the answer right, and the trickster or priest
could disconnect the batteries and no shock would arrive - the
person would then be convinced of the power of the statue, priest
and the religion."
Magical rituals
It is said that to the uninitiated, science cannot be
distinguished from magic. "In Egypt we know this sort of thing
happened with Hero's engine," Dr Craddock says.
Hero's engine was a primitive steam-driven machine, and like the
battery of Baghdad, no one is quite sure what it was used for, but
are convinced it could work.
If this idol could be found, it would be strong evidence to
support the new theory. With the batteries inside, was this object
once revered, like the Oracle of Delphi in Greece, and
"charged" with godly powers?
Even if the current were insufficient to provide a genuine shock,
it may have felt warm, a bizarre tingle to the touch of the
unsuspecting finger.
At the very least, it could have just been the container of these
articles, to keep their secret safe.
Perhaps it is too early to say the battery has been convincingly
demonstrated to be part of a magical ritual. Further examination,
including accurate dating, of the batteries' components are needed
to really answer this mystery.
No one knows if such an idol or statue that could have hidden the
batteries really exists, but perhaps the opportunity to look is not
too far away - if the items survive the looming war in the Middle
East.
"These objects belong to the successors of the people who
made them," says Dr Craddock. "Let's hope the world
manages to resolve its present problems so people can go and see
them."
Source of the above article: BBC NEWS http://news.bbc.co.uk/go/pr/fr/-/1/hi/sci/tech/2804257.stm
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