The data given in Table refer to two limiting cases: pur e dir ect and pur e HOMEC electrolysis. The important question is the determination of t he ar ea of t he nea r elect r ode ef f ect s . To solve this problem, the method near electrode tomography, NELTO is proposed, in which series of mix ed dir ect/H OMEC electrolysis are carried out with a gradual change in the HOMEC contribution . Thus, the decrease in the ratio R = A/B with an increasing share of НОМЕС, cf. Table , clearly reflects the pr ofile and length of the effective near-electrode zone, the exact determination of these parameters requires the solution of a diffusionkinetic problem under controlled mass transfer conditions (s. below).