1. F. Bitter:Phys. Rev.,76, 833 (1949).
2. M. H. L. Pryce:Phys. Rev.,77, 136 (1950). We are indebted to ProfessorA. Abragam for bringing references (1) and (2) to our attention when we informed him of our results.
3. A preliminary experimental attempt was reported byE. C. Avery, C. Little-John, G. J. Perlow andB. Smaller at the Allerton Park Conference, University of Illinois (June 1960).
4. M. N. Hack:Phys. Rev.,100, 975 (A) (1955);104, 84 (1956);H. Salwen:Phys. Rev.,99, 1274 (1955);C. Besset, J. Horowitz, A. Messiah andJ. M. Winter:Journ. Phys. et Rad.,15, 251 (1954);J. M. Winter:Ann. Phys.,4, 745 (1959).
5. V. Weisskopf andE. Wigner:Zeits. Phys.,63, 54 (1930).