They are subtle energies that you can sense only through your feelings.
A subtle but lively energy gradually seems to expand in the lovely old church.
They are of a similar subtle energy or material, just as our own bodies are.
Eventually a practitioner has experiences which are viewed as knowing the subtle energies of one's being.
This was done, on certain occasions by deliberate ritual, to maintain the subtle energies at a site as well as the physical features.
The retina is a kind of photoelectric material, which emits subtle energy when exposed to light.
Hence, very subtle electric energy starts flowing from the retina.
Thus, the hand is a conduit of subtle energy.
He believed that this result was a consequence of the flow of subtle energy between himself and the patient, rather than any physical intervention.
If it exists, which I think it does, it's a subtle, higher energy.