1. Mendoza, E. B., Cérémonies Langevin–Perrin, Paris (1948).
2. McLennan, J. C., Allen, J. F., and Wilhelm, J. O., Trans. Roy. Soc. Canada, 23, (III), 283 (1929); 25, (III), 13 (1931).
3. Meissner, W., and Voigt, B., Ann. d. Phys., 7, 917 (1930).
4. Goodman, B. B., and Mendoza, E. B. (to be published).
5. Daunt, J. G., and Heer, C. V., Phys. Rev., 76, 1324 (1949).