In June of 1936 workers moving earth for a new railway uncovered a ancient tomb
from the Parthian
period. Among the usual pottery
bricks, and metal trinket
s found in the tomb was a clay jar
containing a copper
tube with one closed end and an iron rod
After examining the artifact in Britain, physicist Walter Winton suggested that should someone pour an acid, such as vinegar, into the copper tube, the result would be a simple battery which would generate voltage. Several of these jars placed in series would generate enough current to drive a small electric motor. The discovery of several other jars in the Parthian ruins of Cresiphon seemed to strengthen this hypothesis, and experiments in the United States using replica jars produced a battery that generated a 1/2 volt current for almost three weeks.
Without any other explanation, archaeologists began to wonder why the ancient world use batteries. It was well known that the Babylonians used electric fish as an anesthetic. It's quite possible that these batteries served as a substitute. It is also possible that the batteries were used for electroplating jewelry, as the amount of current is definitely sufficient, and primitive techniques for electroplating still exist in Iraq.
Whatever their purpose, these "Baghdad Batteries" still remain an intriguing mystery to the archaeological community.