Instrument invented by psychical researcher Paul Joire to demonstrate the existence of a nervous force acting externally to the body. In the center of a horizontal dial, marked out in 360 degrees, is a light needle or pointer, usually of straw, balanced by a pivot on a glass support. The device is covered with a glass shade.
When the extended fingers of a hand are at a right angle to the pointer, near the shade without touching it, reportedly, after a few seconds, the pointer moves toward the hand in the majority of cases. This movement extends between fifteen and fifty degrees. Certain substances that had been previously held in the hand also produce this movement. Wood, water, linen, and cardboard appear to store up this nervous energy. Tinfoil, iron, and cotton produce no effect.
The Society for Psychical Research, London, and some French scientific groups attributed the movement of the needle to the action of radiating heat rather than psychic force.
(See also Biometer of Baradoc ; De Tromelin Cylinder ; emanations ; exteriorization of sensitivity ; Magnetometer )