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According to Al Mann, this was invented by Edward T. Goddard and published in an unidentified 1926 magazine see Mann's The Psychic Ring, p. 13). However, this seems unlikely, given “Improved Examined Ring on Cord” in Elliott's Last Legacy, 1923, p. 265, which is clearly an elaboration on the standard method. Will Avis describes the trick in his “Tricks for All” column in the March 20, 1909, issue of Goldston's The Magician, p. 43. It is unclear if all the tricks presented in his column were claimed as original, but it seems so. Avis does offer a nice touch, by using a clear glass bracelet.