Today "demonstration of mediumship" is part of the church service at all churches affiliated with the National Spiritualist Association of Churches (NSAC) and the Spiritualists' National Union (SNU). Demonstration links to NSAC's Declaration of Principal #9. "We affirm that the precepts of Prophecy and Healing are Divine attributes proven through Mediumship."
In 1891 at a public séance with twenty sitters the medium Cecil Husk was caught leaning over a table pretending to be a spirit by covering his face with phosphor material. The magician Will Goldston also exposed the fraud mediumship of Husk. In a séance Goldston attended a pale face materialization appeared in the room. Goldston wrote "I saw at once that it was a gauze mask, and that the moustache attached to it was loose at one side through lack of gum. I pulled at the mask. It came away, revealing the face of Husk." The British materialization medium Annie Fairlamb Mellon was exposed as a fraud on October 12, 1894. During the séance a sitter seized the materialized spirit, and found it to be the Mellon on her knees with white muslin on her head and shoulders.
^ "Glossary of Key Words Frequently Used in Parapsychology" Archived 2010-12-24 at the Wayback Machine, Parapsychological Association website. "Materialization: A phenomenon of physical mediumship in which living entities or inanimate objects are caused to take form, sometimes from ectoplasm." Retrieved January 24, 2006 "Medium – Definition". Dictionary.com. Retrieved 23 March 2007.