The magician Julien Proskauer revealed that the levitating trumpet of Jack Webber was a trick. Close examination of photographs reveal Webber to be holding a telescopic reaching rod attached to the trumpet, and sitters in his séances only believed it to have levitated because the room was so dark they could not see the rod. Webber would cover the rod with crepe paper to disguise its real construction.
In 1936, the psychical researcher Nandor Fodor tested the Hungarian apport medium Lajos Pap in London and during the séance a dead snake appeared. Pap was searched and was found to be wearing a device under his robe, where he had hidden the snake. A photograph taken at a séance in 1937 in London shows the medium Colin Evans "levitating" in mid air. He claimed that spirits had lifted him. Evans was later discovered to be a fraud as a cord leading from a device in his hand has indicated that it was himself who triggered the flash-photograph and that all he had done was jump from his chair into the air and pretend he had levitated.
In the 1920s the British medium Charles Albert Beare duped the Spiritualist organization the Temple of Light into believing he had genuine mediumship powers. In 1931 Beare published a confession in the newspaper Daily Express. In the confession he stated "I have deceived hundreds of people…. I have been guilty of fraud and deception in spiritualistic practices by pretending that I was controlled by a spirit guide…. I am frankly and whole-heartedly sorry that I have allowed myself to deceive people." Due to the exposure of William Hope and other fraudulent spiritualists, Arthur Conan Doyle in the 1920s led a mass resignation of eighty-four members of the Society for Psychical Research, as they believed the Society was opposed to spiritualism.
In 1880 the American stage mentalist Washington Irving Bishop published a book revealing how mediums would use secret codes as the trick for their clairvoyant readings. The Seybert Commission was a group of faculty at the University of Pennsylvania who in 1884–1887 exposed fraudulent mediums such as Pierre L. O. A. Keeler and Henry Slade. The Fox sisters confessed to fraud in 1888. Margaret Fox revealed that she and her sister had produced the "spirit" rappings by cracking their toe joints.