The oxidation of ferrous ion and the reduction of ceric ion in 0.80  Nsulphuric acid by electrons from dissolved P32and S35have been studied. The chemical yields (chemical change per unit energy absorbed) obtained agree well with those obtained using X or γ-radiation. The yield is independent of electron energy above about 5 kev. The results show that chemical dosimetry methods may be used for the accurate determination of energy absorption for electron energies as low as 45 kev. or X rays of 200 kev.