CRYSTAL-GAZING or SCRYING, the term commonly applied to the induction of visual hallucinations by concentrating the gaze on any clear deep, such as a crystal or a ball of polished rock crystal. Some persons do not even find a clear deep neces sary, and are content to gaze at the palm of the hand, for example, when hallucinatory pictures, as they declare, emerge. Among ob jects used are a pool of ink in the hand (Egypt), the liver of an animal (tribes of the North-West Indian frontier), a hole filled with water (Polynesia), quartz crystals (the Apaches and the Euahlayi tribe of New South Wales), a smooth slab of polished black stone (the Huille-che of South America), water in a vessel (Zulus and Siberians), a crystal (the Incas), a mirror (classical Greece and the middle ages), the finger-nail, a sword blade, a ring-stone, a glass of sherry, in fact almost anything. For a discussion of the problems raised by crystal gazing and similar practices, see DIVINATION ; PSYCHICAL RESEARCH ; SPIRIT UALISM and allied articles.