Light
Spiritualists believed that light had a destructive effect upon the physical phenomena of Spiritualism, which psychic research attempted to document. Quite apart from the fact that darkness hid much fraud, Spiritualists developed arguments to suggest that light had an inherent inhibiting effect on psychic phenomena. For example, it is known that light waves have very rapid vibrations (the visible light waves are from 3900 angstroms to 7700 angstroms; that is, the wave lengths range from 0.00000077 to 0.00000039 meters). Broadcasting practice demonstrates that the fast vibrations tend to nullify the slower vibrations on which radio is based. When the days are long and the sunlight intense, radio reception drops down. With the on-coming of night it improves again. With short waves which vibrate faster, reception is better.
It is claimed that psychic vibrations are in the same position. The slowest light vibration is red, and its destructive effect is correspondingly less. Filtering of daylight by glasses of various colors makes little difference. Cold light, devoid of actinic rays, is the least injurious. "I have had many opportunities," wrote Sir William Crookes, "of testing the action of light of different sources and colours, such as sunlight, diffused daylight, moonlight, gas, lamp and candle light, electric light from a vacuum tube, homogeneous yellow light, etc. The interfering rays appear to be those at the extreme end of the spectrum." He found moonlight ideal.
Sulphide of zinc or calcium screens have also been tried. They have the disadvantage that their illumination is poor unless they are extremely large, and the intensity of their phosphorescence rapidly diminishes. Gustav Geley experimented with biological light. It did not appear to affect the phenomena. However, the cultures of photogenic microbes are very unstable. In Brazil, luminous insects were tried with some apparent success.
Meanwhile, some of the more notable mediums worked primarily in lighted rooms and were able to produce extraordinary phenomena. D. D. Home seldom sat in darkness. Eusapia Palladino once levitated a table in blazing sunshine. French psychic researcher Dr. Joseph Maxwell was probably right in stating that the action of light is not such as to constitute an insurmountable obstacle to the production of telekinetic movements.
You can find quite a few very talented mediums profiled on this website, who worked exclusively in well-lit rooms with overhead lighting illuminating everything in the room. Although none of them reported that a well-lit room helped their psychic abilities, in an era where con artists vastly outnumbered genuine Spiritualists, having psychics able to work in those sorts of conditions helped validate not only their word but the works of others as well.
The supposed problem of light was highlighted in an incident reported in the issue of Psychic Research (January 1930). According to a communication by Irving Gaertner of St. Louis, Missouri, in a sitting with Eveling Burnside and Myrtle Larsen in Camp Chesterfield, Indiana, a ray of light, owing to the turning of a switch outside, penetrated through a crack between the lower edge of the door and the floor into the seance room.
"Agonized groans were heard (presumably from the entranced medium, Mrs. Larsen) and one of the two trumpets which had been levitated for the voice immediately fell at the feet of Mr. Nelson. At the same moment, Mrs. Nelson received an electric shock which formed a blister on one of her fingers, resembling one which would be produced by a burning of the skin. All the sitters testified to having felt the electric shock both in the region of the solar plexus, the back and the forehead."
Larsen was reportedly discovered prostrate on the floor, minus any heartbeat and her body rigid. It took considerable effort to restore her to consciousness. Burnside, the other medium, suffered from the shock for several days after the sitting. Frederick Bligh Bond, editor of Psychic Research, speculated about the nature of the electric shock: "Is it the light, qua light, which in this case causes the violent disturbance of conditions, or is it light as an avenue of conductivity, linking the psychic circuit to the current on the wires of the lamp in the hall?"
The dangers of the shock from unexpected light were considered an interesting matter in J. Hewat McKenzie 's report on the mediumship of Ada Besinnet in the April 1922 issue of Psychic Science. The smallest red spark burning was sufficient to prevent the medium from going into trance.
"Upon another occasion, when drawing the electric plug from the wall socket, behind a piece of furniture, and about 8 feet from the medium, the small spark, about 1/16 inch long, which usually accompanies the withdrawal of a plug of this kind when the power is on, was sufficient to create such a psychic shock that the medium immediately fell forward on the table in a cataleptic state."
That psychic structures may objectively exist beyond the range of our optical capacity was demonstrated by quartz lens photography. The quartz lens transmits ultra-violet rays to make visible on the photographic plate things not visible to the eyes. Mrs. J. H. McKenzie and Major Mowbray experimented in this field with the mediums J. Lynn and Lewis. The quartz lens not only disclosed fluorescing lights; vibrating, spinning substances; and psychic rods, but also the dematerialization of the medium's hand when added force had to be borrowed.
Similar results were achieved by Daniel Frost Comstock in seances with "Margery the Medium" (Mina Stinson Crandon) in Boston. Several of his exposed plates showed curious, indefinable white patches, one of which was fairly recognizable as a human face, although it could not be identified. The most important advance in this field of research was registered at the Institut Metapsychique International in Paris with the mediumship of Rudi Schneider in 1931.
Over the first half of the twentieth century, critics claimed that the alleged destructive effect of light on psychic phenomena and the health of the medium were a subterfuge to cover fraud in the darkness of the seance room. In no case was any true physical harm done to mediums by the shining of light, and over the long run, physical mediumship of the type popular in the early twentieth century disappeared under the scrutiny of psychic researchers and the continued improvement of observational techniques.
Light
As Publish by Zerdini in: http://www.spiritualistchatroom.forumotion.com/