Spiritualism- the belief that it is possible to communicate with the dead.
It all started with two young girls playing a prank in 1849, and grew into a movement that is still active today.
Of course, with a premise that is difficult to prove or disprove, it did not take long for some people to realize that there was money to be made.
The spiritualist movement quickly attracted the so called "fake mediums" who pretended to speak with lost loved ones, producing their voices through spirit horns, concocting their ghostly images, and even claiming to receive messages through OuiJa boards or rapping hands.
Houdini railed against these mediums, and even revived his career in 1925 with a year-long tour of his full evening theater show in which he exposed the trickery used by these con artists.
Spirit rapping hands were frequently used by mediums who specialized in seances, especially seances held in private homes.
Hands were familiar objects, seemingly innocent and not magical. Since they were freely examined by the spectators, and placed by one of them on the board, which was held by the medium and several other spectators, it was easy to convince everyone that any movement of the hand could not possibly be caused by trickery, but rather- by the spirits themselves!
Here are several of the Spirit Rapping Hands in my collection.