Phenomena of knockings or rappings have usually accompanied
poltergeist disturbances, even before the commencement
of the modern Spiritualist movement. Thus they were observed
in the case of the Drummer of Tedworth, the Cock
Lane Ghost, and other disturbances of the kind, and also in
the presence of various somnambules, such as Frau Frederica
Hauffe, known as the Seeress of Prevorst.
With the Rochester Rappingsthe famous outbreak at
Hydesville in 1848to which may be directly traced the beginning
of modern Spiritualismthe phenomenon took on a new
importance, rapidly increasing to an epidemic, remaining
throughout the earlier stages of the movement the chief mode
of communication with spirits.
Although it was afterward supplanted to some extent by
more elaborate and complicated phenomena, it continued to
occupy a place of some importance among the manifestations
of the séance-room into the early twentieth century. It is apparent
from descriptions furnished by witnesses that raps varied
considerably both in quality and intensity, being sometimes
characterized as dull thuds, sometimes as clear sounds like an
electric spark, and again as deep, vibrating tones.
It has been shown that raps may be produced by the movement
of various body parts (ankle-joints, knee-joints, shoulders,
and other joints), and one man, Rev. Eli Noyes, claimed
to have discovered seventeen different methods.
There are also instances on record where specially constructed
medium tables were responsible for the manifestations.
Besides the Spiritualist explanation and the frankly skeptical
one of fraud, there have been other scientific (and pseudoscientific)
theories advanced which ascribe the raps to various
forces such as od (or odyle), ectenic force, or animal magnetism.
(See also Raps)
Brown, Slater. The Heyday of Spiritualism. New York Hawthorne
Pearsall, Ronald. The Table-Rappers. New York St. Martins
Pond, Mariam Buckner. Time Is Kind. New York Centennial