First Battery 2,200 years old

There was a battery invented much earlier then our modern version of batteries.  The "baghdad" battery has been discovered, unsurprisingly, near Baghdad, Iraq.  The Battery is 2,200 years old, and is the oldest battery known to man. I'm aware that this is old news, but it is still interesting regardless.

The housing of the battery is a clay jar 5.5" high and 3" across.  The jar houses a hollow copper tube that was positioned vertically. An iron was placed inside of the copper tube, it hung from a asphalt plug positioned at the top of the jar.



When the Jar was filled with vinegar, or any other acidic liquid, the battery created a current from the copper tube to the iron rod.  The battery is capable of producing 2 volts.

The purpose of the battery is uncertain, and there are several different theories.  One theory is that the battery could have been used for medical treatments, as the Romans were known to shock themselves with electric fish and eels as a pain killing treatment.  Other theories suggest that the batteries could have been used for electroplating gold onto silver.