MAGNETIC RESONANCE. II 405 



work on other atoms are listed there. For the deterniination of the proton moment 

 see Gardner, Phys. Rev. 83, p. 996, 1951, and Sommers, Hippie and Thomas, ibid. 

 80, p. 487, 1950. For the measurementof g with F-centres see Hutchinson and Noble, 

 ibid. 87, p. 1152, 1952, and Tinkham and Kip. ibid. 83, p. 657, 1951, and Schneider 

 and England in P.I.C.S.R.; this last is also the source for the work ion zinc sulfide 

 phosphor. For resonance of conduction-electrons see Griswold, Kip and Kittel, 

 Phys. Rev. 88, p. 951, 1952, and papers yet to be published. 



The resonance-peak of Fig. 2 of Part II of this article, for porphyrexide, comes 

 from Holden, Yager and Merritt, /. Chem. Phys. 19, p. 1319, 1951. The literature 

 of resonance in strongly paramagnetic salts is extensive and tough; I refer to the 

 papers in P.I.C.S.R. and the references they give. The basic theory is to be found 

 in the book of J. H. Van Vleck, Electric and Magnetic Susceptibilities (Oxford, 

 1932). 



Hyperfine structure of electron resonance was discovered by the late R. P. 

 Penrose (see Nature, 163, pp. 988 and 992, 1949). This field is almost a monopoly of 

 Britain and in particular of Oxford; many of the papers bear the name of Bleaney 

 with or without collaboratores. Fig. 3 of Part II of this article comes from Proc. 

 Phys. Soc. 63, p. 1369, 1950; the statements about vanadium 50 from ibid. 66, 

 p. 952, 1952. 



The discoverer of ferromagnetic resonance was J. H. E. Griffiths (see Nature, 

 158, p. 670, 1946). The precession-theory for ferromagnetic substances is due to 

 Kittel; equation (21) of this article is derived in Phys. Rev. 71, p. 270, 1947; a fuller 

 treatment appears ibid. 73, p. 155, 1948. Survey articles are those of Van Vleck in 

 P.I.C.S.R. and Kittel in Jour, de Phys., 12, p. 291, 1951. Fig. 4 comes from the 

 paper of Yager and Merritt, in Phys. Rev. 73, p. 318, 1949; a similar curve for 

 supermalloy appears in the preceding paper; references to the ^-values of other 

 ferromagnetic substances are given by Yager. The question of ''g versus g'" is dis- 

 cussed by Kittel in Phys. Rev. 76, p. 743 (1949). 



