As Tim says,  I meant a kind of presence that would linger after an encounter.
The image of a sheathe, or cloak (which I think in this case is pretty
similar) is simply a way to attach some qualities to that presence - light,
bright, and clear.  This way Pound is not talking about some abstraction, but
a real, felt, quasi-corporal Thing.
Tim asked where the exactitude in matters of love comes from, and the idea of
soul-symmetry -  I don't know the answer to that, but suspect that somewhere
in "The Spirit of Romance" there will be clues- I'll wander through those
pages as soon as I can.
Jay