Lasted edited by Andrew Munsey, updated on June 14, 2016 at 8:46 pm.
Directory:Thomas Townsend Brown discovered an effect which may be related to the electrogravitic effects observed upon condensers at high voltage. He noted that certain dielectrics, and most notably certain types of igneous rocks, exhibited a weak electrical potential. Through testing, he discerned that this was neither piezoelectric (pressure induced voltage), nor pyroelectric (heat-change induced voltage), but petrovoltaic. This is to say that there was a continuous, steady voltage across the rock, which changed very slowly, according to the lunar cycle, positions of stars, position of the sun, and such like. http://nicholortberg.blogspot.com/2007/08/petro-electrical.html
John Hutchison is well known for having advanced this effect.
No commercial applications are known or likely due to the low power density.
http://www.qualight.com/petro/ - T. T. Brown
http://nicholortberg.blogspot.com/2007/08/petro-electrical.html - Blog
http://www.ulinkx.com/video/26433 - John Hutchison video clip
http://www.guns.connect.fi/innoplaza/energy/story/John/ - Hutchison Effect archive (crystal batteries)
http://www.nic.funet.fi/pub/sci/physics/effects/Hutchison/ - Hutchison Effect archive (better link)
http://freeenergynews.com/Directory/Inventors/JohnHutchison/index.html - Dirt Cheap Rocks of Hutchison Link
To further explore the topic of petrovoltiacs and their origin, a brief mention of the Hutchison Effect is in order. Canadian inventor John Hutchison discovered that by utilizing Tesla coils and other RF generation apparatus in his lab, he was (often) able to produce strange effects such as levitation, fusion of dissimilar items such as metal with plastic, and other strange effects. He would try different frequencies and RF combinations and sometimes the effect would present itself in strange "poltergeist" fashion. Levitation of a large cannonball, levitation of ice cream in a cup and other strange anomalies are reported with the Hutchison Effect (composite mix of RF fields), as can be found with Google web search on the subject.
Notable as applied to this article are Hutchison's claims to creation of new alloys using this Hutchison Effect. The net result according to Hutchison is that some of the alloys exhibit petrovoltaic properties, e.g. they appear to conduct electricity in a manner that would seem to suggest they gather or "detect" aetheric or other cosmic energy and produce a voltage which can be tapped and read by an ordinary multimeter. Basically according to Hutchison, this effect has produced special "rocks" which show a voltage when tapped at certain points on the objects in question. He has also doped other materials and created these "aether batteries" in the lab by his own report.
In order to avoid drawing an unscientific conclusion regarding Hutchison's claim to aether voltage from special alloys (rock silica etc) it is my opinion that simple RF interference should be ruled out experimentally using accepted scientific methods, as a SI or GE diode makes a great crystal radio detector. A diode takes a signal such as an RF carrier and rectifies or processes this signal. Thus it acts as an RF detector capable of receiving RF energy in a radio.
Hutchison is seen reading voltages from one of his special (composition unknown) alloys in a web video. According to his multimeter the voltage and current seems to emanate freely and with no obvious outside excitation. I would venture that it would be feasible to electrically isolate the material in an RF shielded building (bunker etc). Such an electrically shielded room would serve to best eliminate the possibility that the supposed petrovoltaic detector wasn't merely rectifying standard man-made signals. While I do not believe this is the case, it is worth further investigation to adhere to the scientific method and eliminate as many possible avenues of interference or "false positives" as feasible with any experimental technology.
After further review, it would seem that Brown has done a great deal of the necessary research using methods along the lines of those suggested by scientific method best practices (Naval Research link to be added).
This effect using silicas and other materials (crystal and other detectors) use physical pressure to create a voltage, such as the voltage created in a crystal earphone or crystal microphone. Crystals are often used as detectors in lieu of standard diodes. Inherent in this is the fact that crystals exhibit resonance, which makes them ideal to selectively tune in a signal of a certain frequency. The marked similarity of piezoelectric effects as compared to that of petrovoltaic effects lend me to group them in a not dissimilar category. That is to say, both piezo and petrovoltaic materials tend to exhibit detection properties. Hence this could provide another clue to the mystery of petrovoltaic operation, given proper research and experiments along these lines.
See also Directory:Piezoelectric
: "I am no expert on this subject matter, but I do find the idea of using rocks and crystalline structures as an aether "battery" fascinating. I like to research the Hutchison Effect, T. T. Brown and Nikola Tesla, since such matters tend to pique my curious nature." -- Ray (Nov. 7, 2007)