Hi Stefan & all,
nice to see you've got a summary of our Hutchinson/Reid cell discussion posted!
I'd just like to add the stuff I dug up on the petroelectric effect, which appears
to be directly related.
The presence of potential differences in certain natural (and artificial) rock types
was researched and documented by Townsend T. Brown a decade or 3 ago,
and termed petroelectrical effect (or petrovoltaics). He found it was present
in certain types of granite, as well as certain basalt rocks, and was able to measure
a couple of millivolts and milliamperes by painting copper strips on opposing sides
of samples of these rocks, and attaching them to sensitive measurement equipment.
Later on he found out that these rocks generally had a high dielectric constant (K),
and tested a few artificial dielectric materials for the same effect successfully.
The materials he mentions include barium titanate, lead zirconate, tungsten carbide,
and lead monoxide, as well as certain oils. This effect therefore is clearly not
confined to crystalline solids, although atmittedly those are easier to work with.
He found this effect to be distinct and seperate from the piezoelectric and
pyroelectric effect, although I cannot find any documentation that clearly
shows he tested the materials under constant low or high temperatures to
prove the latter, nor regulated pressure or vacuum ot prove the former.
He must have tried some variations in ambient conditions in order to reach
that conclusion, however.
In any case, he termed it petroelectric effect because he first found it in
solid natural rock types, and I do not at this time see any reason to challenge
the name of the effect, for it does not change the nature of the effect at all.
For more information on T. Brown's research into this, see this link:http://www.soteria.com/brown/docs/epetro
It contains all of Browns typed documentation on the petroelectric effect.
It seems Marcus Reid came across this effect in natural calcite, and
did his own research, parallel to and independently from that of Brown,
although apparently confined to the effect in calcite material.
How Hutchinson came across the effect remains unclear, he may have
stumbled upon it himself or also found Browns documentation.
Interestingly, Hutchinson apparently claims to have built versions
of 'his' power source that produce up to a number of kiloVolt,
which is quite encourageing for experimentors. Also, it is mentioned
in certain articles about Hutchinsons Japan tour that he mentioned
he used barium titanate in some of his prototypes... Brown clearly
mentions barium titanate as one of the dielectrics that show a
petroelectric effect. Another encourageing fact.
Another article (found on www.hutchinsoneffect.com
how Hutchinson used 'metal coated quartz plates', and I cannot
help to think that it is interesting that granite consists among other
things of quartz.
Whether or not the petroelectric effect is completely disconnected from
piezoelectrics is not entirely clear to me, since I know that both quartz and
barium titanate exhibit piezoelectric properties...
Perhaps all of the materials Brown mentions do...? Perhaps calcite does
Not that it matters much for the experimentor who wants to build
a 'battery'/'power source' based on this effect, of course. Whatever
the relation between petro- and piezo-electric effects may be, the
battery will still work.