Eric,
A traditional Wimshurst electrostatic generator consists of two disks each with a band of foil sectors near the rim of each disk.
The sectors carry electrical charges from one side of the machine to the other. A charged sector on one disk causes a charge
to be moved on the other disk from one edge to the opposite edge by means of a connecting brush assembly. This process occurs at
four locations, two on each disk. The type of machine that I've built dispenses with the metallic sectors and uses charges sprayed
directly onto the surface of highly insulating fiberglass disks.
Such a machine is called a Bonetti machine after its inventor. A triplex machine uses multiple disks to greatly enhance the current.
This link provides more info on maqny designs of electrical inventions of the 18th and 19th centurys.
http://www.coe.ufrj.br/~acmq/electrostatic.htmlThe first picture on this site is of a Wimshurst machine.
Dave