This is a really compelling theory on the production of Piezo-Electricity made through fermentation and pressure in the enormous granite sarcophagi at the Serapeum of Saqqara.
The ancients understood resonance, standing-waves and infra-sound amplification. All the subterranean caverns show no sign of torch carbon burning on the walls or ceilings. I think they likely had wirelessly illuminated light bulbs, like the famous image of Tesla holding his wireless light-bulb.