Note:  Do not rely on this information. It is very old.

Brush Discharge

Brush Discharge, in Electricity, means the discharge of the electricity from a charged body into the surrounding air or other gas, by a process of convection. It will take place most vigorously at the points or corners of the body, for at such places on the surface of a conductor the density of the electrical charge is greatest. Particles of air near some such point are electrified by induction and drawn into contact with the conductor, thereby receiving part of the charge. Possessing this, they are repelled on account of the tendency for two quantities of electricity of the same kind to increase their distance apart. Thus the charge in the body is carried off by the air, currents of which may be readily observed to proceed from the sharp corners and points during discharge. The brush discharge is faintly luminous, very small sparks occurring at the contact of the air particles with the conductor.