Captromancy, also known as Catoptromancy, Enoptromancy, Catoxtromancy or Caloptromancy is a form of divination that uses a mirror and is similar to crystal gazing.
From Greek katoptron, mirror, and manteia, divination
Captromancy is a very ancient form of crystal gazing, and was practiced extensively by the Achaians, Greeks and Romans.
A mirror is placed so that it catches a reflection of another substance. Usually this is something that is hard to hold, for example moonbeams or water reflections. Then the reflections in the mirror are interpreted.
Another method, used for 'medical' prognostications, involved hanging the mirror by a thread over a fountain or pool of water. After the mirror was slowly lowered until its base barely touched the surface of the water, some incense was burnt and prayers were recited. The presage of death or recovery was arrived according as the to the face that appeared in the mirror. If it was a fresh and healthy image, recovery was imminent; but if instead a ghastly aspect was represented, death was sure to come swiftly.
Another divinatory method of using a mirror was to place it at the back of a boy's or girl's head when their eyes were bandaged shut. In Thessaly the responses appeared in characters of blood on the face of the moon, probably projected in the mirror. This practiced was derived by the Thessalian sorceresses from the Persians who wanted to establish their religion and mystical rituals in the countries which they invaded.
Pausanias, an ancient Greek traveler, described as follows:
Before the Temple of Ceres at Patras, there was a fountain, separated from the temple by a wall, and there was an oracle, very truthful, not for all events, but for the sick only. The sick person let down a mirror, suspended by a thread till its based touched the surface of the water, having first prayed to the goddess and offered incense. Then looking in the mirror, he saw the presage of death or recovery, according as the face appeared fresh and healthy, or of a ghastly aspect.
In ancient Rome, special diviners known as “blindfolded boys” were known to gaze into looking glasses in order to experience visions of the future or of the unknown, and according to the 4th century 'Scriptores Historiae Augustae', the death of Julian the Apostate was accurately predicted by Catoptromancers.