Step 5: Charging the Leyden jar
Update: I measured the capacitance with a handheld digital meter and got consistent results of 00.32 nF (that's 320 pF) for this model Leyden jar. A variant of the Soda Can Leyden jar made with polypropylene bottles rates as high as 00.50 nF (500 pf).
Connect the outside of the jar to a ground, such as metal stove top or metal water pipe. Run a connecting wire from your charging device (a Wimshurst machine, Van de Graaff, ion generator, etc) to the center brass post. The jar will take on charge until it reaches capacity. It may arc over (spontaneously discharge) if over filled.
You can also charge these jars from TV screens, friction rods, and any other source of static electricity.
Stringing a number of these jars in parallel will create a *very* powerful capacitor bank! Be sure to discharge the jar with a U-shaped piece of wire held in an insulated handle. You will get loud, powerful sparks from this device. Leyden jars can recover charge if left sitting, so for safe storage short out the jar by clipping a wire to the center electrode and having it touch the outer foil coating.