Magicians have a long history of exposing the fraudulent methods of mediumship. Early debunkers included Chung Ling Soo, Henry Evans and Julien Proskauer. Later magicians to reveal fraud were Joseph Dunninger, Harry Houdini and Joseph Rinn. Rose Mackenberg, a private investigator who worked with Houdini during the 1920s, was among the most prominent debunkers of psychic fraud during the mid-20th century. https://drive.google.com/file/d/1wG2ulsB-R-75Z6Sg2tA1niFATuwHYtU8/view?usp=sharing
"Mental mediumship" is communication of spirits with a medium by telepathy. The medium mentally "hears" (clairaudience), "sees" (clairvoyance), and/or feels (clairsentience) messages from spirits. Directly or with the help of a spirit guide, the medium passes the information on to the message's recipient(s). When a medium is doing a "reading" for a particular person, that person is known as the "sitter". https://drive.google.com/file/d/1GEKx89qSKkJWI3i0M9kXg4Jy6OlYi_Qz/view?usp=sharing
Clairvoyance. Clairvoyant mediums can see spirits, auras, objects and places that are not perceptible to others. People who have passed away may appear to them in visions, or they may be able to vividly sense a place to which they have never been. Psychic mediums see these visions with their third eye, located between the two physical eyes. Everyone has a third eye, but the average person's is closed or too weak to use.
In the late 1920s and early 1930s there were around one quarter of a million practising Spiritualists and some two thousand Spiritualist societies in the UK in addition to flourishing microcultures of platform mediumship and 'home circles'. Spiritualism continues to be practised, primarily through various denominational Spiritualist churches in the United States, Canada, Australia and the United Kingdom. In the United Kingdom, over 340 Spiritualist churches and centres open their doors to the public and free demonstrations of mediumship are regularly performed.