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On February 22 Leigh Palmer wrote
I'm unsure of what is meant by "chemical energy" in this or any other
context. This phrase, like "heat energy" is a trap. Energy is energy.

Yes, a lot of interesting depth is hidden behind each form of energy.
Chemical energy does have an accepted meaning; it is potential energy
of forming molecules (from atoms or from other molecules). As far as I
know, no chemical energy is involved in charging and discharging of a
Leyden jar. Yes, work done to polarize molecules of glass goes into
potential energy but I would not call it chemical energy (unless you
convince me that SiO2 changes into something else).

I would infer, from your description of the rebounding of voltage in
glass, that polarizational potential energy does not dissipate entirely
when the Leyden jar electrodes are connected for a short time.

Leigh also wrote:
If the behaviour of the supercap on rebounding after discharge is taken
to represent this arcane sort of energy, then it must mean equally that
a capacitor with a glass dielectric stores chemical energy, too. ...
Kinescopes are capacitors. They are effectively Leiden jars. ....
The rebound phenomenon with a glass dielectric capacitor is quite
dramatic. You can demonstrate it with a Leiden jar as well. In fact I
do it with a disassemblable Leiden jar. I can charge the jar and remove
the aluminum electrodes. After touching them together, I replace them and
a healthy arc can be drawn off the jar. After a minute or so I can draw
another spark.

Very interesting; I did not know about multiple sparks in jars. What does
the removal of electrodes have to do with the showing of these sparks?

The capacitance of an electrolytic is simply the parameter Ludwik
measured in his experiment. No electrolytic, supercap or otherwise,
behaves linearly.

How do manufacturers determine C; from the discharge rate or from the
defining equation, Q=C*V? For your Leyden jar both of these approaches
are likely to yield practically the same C. I found the same to be true
for the non-electorolytic and for the "ordinary" electrolytic capacitors
(C<2200 microfarads) which were tested. Supercaps seem to be unique in
that respect.
Ludwik Kowalski