ClipArt ETC
"When a charge is moved from any point to another point in the same equipotential surface, no work is done upon it. When a charge is moved from one such surface to another, the work done is independent of the path of transfer. If such a surface was to be rendered impenetrable, a particle could lie upon it without tendancy to move along it in any direction. If any two points in such a surface were to be joined by a conductor, no flow of electrification would take place. The closed lines are equipotential lines drawn, upon equipotential surfaces, about two similartly electrified spheres, the quantity of electrifaction at A being twice that at B." -Avery 1895

Equipotential Lines

"When a charge is moved from any point to another point in the same equipotential surface, no work is…