Divination
A psychomantium is based on an old form of divination, known as mirror-gazing. Like many similar techniques it has a shared root in the Oracles of ancient Greece. Much like the associated and ill-favoured Ouija board, it is used to contact the departed spirits of friends or family.
It requires a large mirror, preferably frameless, to aid concentration and remove distractions. The viewer sits reasonably closely in front of this mirror, surrounded by a dark, heavy curtain. A source of light is placed behind the viewer, with a lantern, or several candles being sufficiently bright to obtain the desired low level of illumination.
Importantly, the mirror is angled so that the viewer cannot see their own reflection, but rather the reflection of the dark space within the curtained area. In that respect it is reminiscent of the Pepper's Ghost illusion of early stage dramas, and this may have been exploited by fraudulent characters in the past.
The premise is that the viewer having spent some time previously focussing their thoughts on the person to be contacted then enters the psychomantium, and gazes into the mirror.
Given time and practice, the viewer should be able to summon images from the mirror in a similiar way to the most famous scrying device, the crystal ball. These visions do not require the need for a medium or other external persons and communicate with the viewer in a number of subjective fashions.
The Victorians with their love of mysticism constructed entirely mirrored rooms which were psychomantiums. They have also enjoyed a small burst of popularity in more recent times.
The word "psychomantium" derives from the literal translation of the Latin phrase - "place of necromancy".
Sources
http://astralthyme.com/psychomantium.html
Last updated : 28th January, 2003