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

Lichtenberg Figures

Lichtenberg Figures illustrate the distribution of static charges of electricity on the surfaces of insulators. If a charged body is applied to a sheet of ebonite or other non-conductor, the charge will leak over its surface in an irregular manner, and may be rendered evident by dusting the surface with a fine powder, which adheres to the electrified portions. The shapes of the figures vary according to whether the charge is positive or negative. If different patterns are traced out with two conductors - one positively and the other negatively charged - and if the plate is then dusted over with a mixture of red-lead and sulphur powder by means of a sieve, the two powders will arrange themselves on the two patterns. The red lead becomes positively, and the sulphur negatively, charged by friction with the sieve, and the different powders adhere respectively to the negatively and positively charged parts of the plate.