THE PHYSICAL BASIS OF FERROMAGNETISM 39 



(1) the atomic magnetic moment (determined from the saturation 

 magnetization at 0° K), which gives directly the numbers of electrons 

 in certain shells in the atom, and (2) the gyromagnetic effect, experi- 

 ments on which give results characteristic of an electron spinning 

 about an axis passing through its center. 



Acknowledgment 



I take pleasure in acknowledging the benefit of many discussions 

 with Dr. W. Shockley and of the criticism of the manuscript given by 

 Dr. K. K. Darrow and Dr. R. W. King. 



