Leyden jar, late 18th century. This was inv
© Science Museum / Science & Society Picture Library
Leyden jars were invented by E G von Kleist in 1745. They are devices for storing static electricity, and consist of two conductors separated by an insulator. This jar appears to be earlier than the other Leyden jars in the King George III collection of scientific instruments; the green glas is les perfect and the coating is lead foil. The jar is filled with iron filings.