Inventor: Pieter van Musschenbroek, Ewald Georg von Kleist (separately)

A Leyden jar is a form of an electrical device known as a capacitor. Its purpose is to store electric charges on two separate conducting plates, which in this case are on the inside and outside of a glass jar. The device stores energy in the electric field between the two oppositely charged plates which may be gradually built up and then released rapidly. Although glass Leyden jars are not commonly used anymore, modern capacitors still work in the same way.

Pieter van Musschenbroek invented the Leyden jar in January 1746. He was attempting to electrify water in a glass jar which he held in his had. A wire ran from the water to an electrostatic generator that was being run by his assistant, Cunaeus. When he touched the wire he received an enormous and unexpected shock. He had unknowingly formed a capacitor between his hand and the water in the jar. The capacitor had stored the charge and then released it all at once.

Musschenbroek was not the only experimenter to develop the Leyden jar. Ewald von Kleist had discovered the same effect about a year earlier. However, Musschenbroek developed and experimented with the jar more than von Kleist, and so it became known as the Leyden jar, named after Musschenbroek’s home town in the Netherlands.

The Leyden jar finally allowed experimenters to store the charge they produced with glass rods and friction machines. Because of this, it was probably one of the most important inventions in the 1700s.

Pictures from:
"Pieter (Petrus) van Musschenbroek". 28 Dec. 2003 <http://chem.ch.huji.ac.il/~eugeniik/history/musschenbroek.htm>

Sources:

"Leyden Jars". 1 Jan. 2004. <http://chem.ch.huji.ac.il/~eugeniik/instruments/archaic/
leyden_jars.htm>

• This website provides a history of Leyden jars.

"Leyden Jar". 1 Jan. 2004. <http://45.1911encyclopedia.org/L/LE/LEYDEN_JAR.htm>

• This is a description of Leyden jars and their history.

"Pieter (Petrus) van Musschenbroek (1692-1761)". Corrosion Doctors. 1 Jan. 2004. <http://www.corrosion-doctors.org/Biographies/
MusschenbroekBio.htm>

• This is a short biography of Musschenbroek.

"Pieter (Petrus) van Musschenbroek". 16 Oct. 2002. 1 Jan. 2004. <http://chem.ch.huji.ac.il/~eugeniik/history/musschenbroek.htm>

• This is a biography of Musschenbroek.

"Ewald Jurgens (George) von Kleist". 1 Jan. 2004. <http://chem.ch.huji.ac.il/~eugeniik/history/kleist.html>