366 BELL SYSTEM TECHNICAL JOURNAL 



in addition to the papers already cited, that of H. D. Arnold and G. W. Elmen 

 {Journ. Franklin Inst. 195, pp. 621-632; 1923). The gyromagnetic effect, the data 

 and the theories of paramagnetic substances, and diamagnetism are treated very 

 fully in the above-cited book of Stoner; paramagnetism, and the interesting and 

 important magneto-caloric effects which I had not space to discuss, in the book of 

 Weiss and Foex; diamagnetism in a late article by E. S. Bieler {Journ. Fra^iklin 

 Inst. 203, pp. 211-242; 1927). 



I am much indebted for the comments and counsel and information abundantly 

 given by Dr. L. W. McKeehan during the preparation of this article, and for the 

 opportunity of using several cuts prepared for his article "Ferromagnetism"; to 

 Dr. O. E. Buckley for reading and commenting upon a great part of the manuscript; 

 and to Mr. L. A. MacColl for much collaboration in studying the equations of 

 Ewing's model. 



