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)