Ewald Jurgens Von Kleist (1700-1748) was a German administrator and cleric who discovered, in a Leyden jar (1745), a fundamental electric circuit element for storing electricity, now usually referred to as a capacitor. Pieter van Musschenbroek independently discovered the device about the same time. The Leyden jar consisted of a narrow-necked glass jar coated over part of its inner and outer surfaces with a conductive metallic substance; a conducting rod or wire passes through an insulating stopper (cork) in the neck of the jar and contacts the inner foil layer, which is separated from the outer layer by the glass wall. The Leyden jar was one of the first devices used to store an electric charge.