I think that a Hindu Shiva Lingam is actually a representation of a Faraday generator/motor and that they were originally construction out of a conductive material and that over time the true meaning of it was lost.
Pics for comparison:
Shiva Lingam:
http://www.mountainsoftravelphotos.com/Nepal%20-%20Kathmandu/Gokarna%20Mahadev%20Temple/slides/55%20Kathmandu%20Gokarna%20Mahadev%20Temple%20Shiva%20Lingam.html
(http://www.mountainsoftravelphotos.com/Nepal%20-%20Kathmandu/Gokarna%20Mahadev%20Temple/slides/55%20Kathmandu%20Gokarna%20Mahadev%20Temple%20Shiva%20Lingam.jpg)
(http://www.energyenhancement.org/SHIVALINGAM.jpg)
In traditional Indian society, the lingam is seen as a symbol of the energy and potential of Shiva himself, so it is viewed as an energy source.
Faraday Generator:
(http://www.zamandayolculuk.com/pu-2/unipolgen.gif)
(https://upload.wikimedia.org/wikipedia/commons/1/19/Faraday_disk_generator.jpg)
http://www.zamandayolculuk.com/faradaydisk.htm
(https://upload.wikimedia.org/wikipedia/commons/thumb/a/a6/Faraday_disc.svg/330px-Faraday_disc.svg.png)
https://en.wikipedia.org/wiki/Homopolar_generator
Ancient technology in plain sight...
Cosmo
Vimanas were the aircraft of the ancient Hindus that were described as using a mercury vortex engine.
http://www.thelivingmoon.com/47brotherthebig/03files/Vimanas_Mercury_Vortex_Technology.html
If the Shiva Lingam was a Faraday motor/generator then mercury would have been used. Imagine my surprise when I found out that there is a tradition of mercury associated with the Shiva Lingam called Parad Shivling.
http://www.astroshastra.com/parad/shivling.php
Mercury in a Faraday motor configuration:
https://www.youtube.com/watch?v=1fRC7V3KMA4
I think there is evidence here that shows that the Shiva Lingam was a version of a Faraday motor using mercury and if that is the case then it could have been related to the propulsion system of the ancient Vimanas.
(https://i.ytimg.com/vi/cswBc3yG83M/hqdefault.jpg)
Cosmo