The Leyden Jar, named after the city Leiden, the Leyden jar could store high voltage, (Despite its mundane and safe appearance, the Leyden jar is a high voltage device, and it is estimated that at a maximum the early Leyden jars could collect electrical energy from friction in a range from 20,000 to 60,000 volts ).
The Leyden Jar has metal inside and outside of the container then partially filled with water or other type of liquid, the cap has a nail protruding through it and a ground attached to the outer metal shell…
Sources for the Leyden Jar … Wired.com