This entry contributed by Dana Romero
Built in the mid-1700s at the University of Leyden in Holland, the Leyden jar consisted of a glass jar coated inside and out by a thin foil. With the outer foil being grounded, the inner could be charged by means of an attached rod and chain from a source of static electricity. It was found early on that an operator holding the jar could receive a severe shock by touching the inner foil or the rod, even though the jar had been disconnected from the static source. Thus it was the earliest capacitor.
An interesting development using this phenomenon was the first atom smasher, built in 1930 by Cockcroft Eric Weisstein's World of Biography and Walton Eric Weisstein's World of Biography at Cambridge University. This device used banks of these Leyden jar condensers and reportedly could store up to one million volts.
Capacitor, Static Electricity, van de Graaf Generator, Wimshurst Machine
References
Gamow, G. Biography of Physics. New York: Harper and Row, 1961.
