What is a Leyden Jar? 1
A Leyden jar the earliest form

of the capacitor is a device

for storing an electrical charge.

First described in 1745 by E. Georg van 

Klein (c.1700-1748) it was also used by

Pieter van  Musschenbrook 1687 1761 

a professor of physics at the Universty 

of Leyden.