For constant charges and distances the mechanical force is inversely as the dielectric constant.
This harmonizes with the fact that the real seat of the energy 3f electrification is the dielectric or insulator surrounding the charged conductor.'
Mossotti found a relation between the dielectric constant and the space actually occupied by the molecules, viz.
If the two small conducting spheres are placed with centres at a distance d centimetres, and immersed in an insulator of dielectric constant K, and carry charges of Q and Q' electrostatic units respectively, measured as above described, then the mechanical force between them is equal to QQ'/Kd 2 dynes.
Clerk Maxwell demonstrated, however, that all electric charge or electrification of conductors consists simply in the establishment of a physical state in the surrounding insulator or dielectric, which state is variously called electric strain, electric displacement or electric polarization.