It seemed to him that Sylvia, enfolded in the silvery-dim dusk in the bow, was a part of the peace of sky and water.
They were alone, away from the strifes and jars of the world, shut in together as completely as though they had been flung back for unreckoned ages into a world of unbroken calm.

The peace that Wordsworth sought and sang crept into their blood, and each was sensible that the other knew and felt it and that it was grateful to them both.
Sylvia spoke, after a time, of immaterial things, or answered his questions as to the identity of the constellations mapped in the clear arch above.
"I dream sometimes of another existence," she said, "as I suppose every one does, when I knew a quiet lake that held the stars as this does.

I even think I remember how it looked in winter, with the ice gleaming in the moonlight, and of snow coming and the keen winds piling it in drifts.

It's odd, isn't it?
those memories we have that are not memories.

The metempsychosis idea must have some substance.