It was as if a door had opened somewhere. Or possibly a series of doors. There was a sensation as of a breeze blowing into the house and bringing with it the half-rememberedscents of childhood. There was a shift in the light which seemed to cause all the shadows in the room to fall differently. There was nothing more definite than that, and yet, as oftenhappens when some magic is occurring, both Drawlight and the lady had the strongest impression that nothing in the visible world could be relied upon any more. It was as if one might put out one's hand to touch any thing in the room and discover it was no longerthere.
Susanna Clarke, Jonathan Strange & Mr Norrell
magic