An hypothesized energy field demonstrated by N. Zwaan, Dutch delegate to the International Spiritualist Federation Congress in London in 1948. The Zwaan Rays were supposed to be capable of stimulating the psychic senses into activity. Subsequently the Spirit Electronic Communication Society was founded in Manchester, England, on September 10, 1949, and an apparatus was developed that claimed to improve the Zwaan effect.
(See also Ashkir-Jobson Trianion )
Dyne, Mark. Electronic Communication for the Spiritual Emancipation of the People. Rev. ed., Manchester, England: The Spirit Electronic Communication Society, 1954.