“…A more exact expression due to Prof. Dr. Freidrich A . Sauer of the Max-Planck Institute for Biophysics in Frankfurt, Germany, and derived not on the less precise basis of energy conservation as was the above expression, but on the conservation of momentum so as to better account for frictional losses, etc., is (11) where b = (K& -Kl,tot)/Kl,,,,,, K,,, = K + js/(e,W), the complex relative dielectric constant, b* is the complex conjugate of b, and s is the specific conductivity. The two expressions agree fairly well for situations in which the conductivity is not too high.…”