the little jar from Khujut Rabu that won't shut up (Baghdad Battery)

not strictly my region I know but it's THE ancient-tech artifact so allow it. 1936, village called Khujut Rabu just outside Baghdad. they dig up a small terracotta jar, ~13cm, and inside there's a copper cylinder wrapped around an iron rod, sealed at the top with asphalt/bitumen. dated Parthian-ish……