1. Atkins, K. R., Nature, 161, 925 (1948).
2. Daunt, J. G., and Mendelssohn, K., Proc. Roy. Soc., A, 170, 423 (1939); Nature, 143, 719 (1939); ibid., 157, 839 (1946).
3. de Haas, W. J., and van den Berg, G. J., to be published shortly; private communication.
4. Brown, J. B., and Mendelssohn, K., to be published shortly; Brown, J. B., thesis (Oxford, 1949).
5. Mendelssohn, K., and Closs, J. O., Z. phys. Chem., B, 19, 291 (1932).