To scry or descry is to spy out or discover by the eye objects at a distance.
Occultists claim that if one concentrates hard enough while gazing, one can conjure up the dead.
This is possible because, we are told, scrying clears out the consciousness and makes it possible for a direct line to the other world. I am told that if one rubs a crystal ball with mugwort under the light of a full moon, its capacity for igniting psychic powers magnifies. However, as far as I know, there have been no controlled studies to test this, or any other, hypothesis regarding scrying. See related entry on Raymond Moody.