Kelvin electrostatic generator generates static from water

I have been told of a simple apparatus that can generate an electrical potential out of drops of water. Can you give me any guidance as to where I can find details of the construction and the underlying science. I am told that it is called a storm in a teacup.

You may be thinking of the Kelvin electrostatic generator. This takes water from one container and drops it inoto two others. There is a system of loops and wires connected to the "output" cans which feeds back voltages to the input, resulting in the output cans charging to a high positive and negative voltages respectively

http://physicsnt.clemson.edu/physdemo/cat/elecstat/kelvinel.htm

http://www.physics.umd.edu/lecdem/services/demos/demosj2/j2-02.htm

If you search on google you will find other references.