738 
PROFESSOR F. G. BAILY ON THE HYSTERESIS OF 
It is an important part of Professor Ewing’s theory of magnetism that hysteresis 
is caused solely by intermolecular magnetic control, and not by any friction on the 
moving molecule, although there are great temptations to assume some such friction 
Diagram 10. 
in certain phenomena. But the almost complete disappearance of hysteresis in the 
soft iron proves that friction must be almost entirely absent, since an individual 
rotary motion would not avoid this. 
The curve for hard steel is not so conclusive on this point, as the induction has not 
