1. According to the measurements of M. Schranner.
2. Kortüm, G., and D. Oelkrug: Naturwiss. 53, 600 (1966).
3. That the additivity is not exactly within the limits of error can be explained by the differences in the scattering coefficients of both components and of the mixture. This occurs because the mixture was additionally ground whereas the pure components were mixed only by lengthy shaking in a test-tube.
4. See, e.g. Eischens, R. P.: Z. Electrochem. 60, 782 (1956).
5. Terenin, A., and L. Roev: Spectrochim. Acta, 15, 274 (1959).