The Plane of Ethereal Substance comprises that which science speaks of as "The Ether," a substance of extreme tenuity and elasticity, pervading all Universal Space, and acting as a medium for the transmission of waves of energy, such as light, heat, electricity, etc. This Ethereal Substance forms a connecting link between Matter (so-called) and Energy, and partakes of the nature of each. The Hermetic Teachings, however, instruct that this plane has seven sub-divisions (as have all of the Minor Planes), and that in fact there are seven ethers, instead of but one.
