AbstractThe dielectric dispersion of dilute solutions of ethyl cellulose in dioxane was studied using a “differential” bridge method for the range from 200 cycles to 300 kilocycles. The frequency where the dispersion was 0.50 was recorded as the “critical” frequency. The critical frequency is related to the intrinsic viscosity of the samples as log 100[η] = 2.97 − 0.59 (vc). Since the determination of critical frequency is very rapid this method apparently is satisfactory for molecular weight determinations in the syste