Abstract :
Maxwell stated in his “Electricity and Magnetism” that for a non-homogeneous dielectric built up of n plane layers of varying thicknesses and varying ratios of resistivity to specific capacity, the charging current will be given by a linear differential equation of order n-1 involving the nth derivative of the applied e. m. f. This equation and its detailed solution are given here and the two cases of greatest practical interest, — namely the case where the applied e. m. f. is constant and the case where it is a pure harmonic, — are treated fully. By a Fourier analysis the general case can be reduced to these two.