56 Proceedings of the Royal Society of Edinburgh. [Sess. 
loading, and of the negative and positive changes due to unloading, on the 
molecular groups of opposite polarities respectively, is zero — must occur at 
some other position than that of magnetic neutrality. If this hypothesis 
be correct, then, after the irreversible vibrational effects (a) have secured 
permanent stability under the conditions of the various molecular groups, 
these positions, where this nice balancing of the opposing magnetic changes 
due to loading and unloading occurs, constitute cyclic Villari critical points 
in nickel. 
I desire to express my indebtedness to the Royal Society of London for 
placing at my disposal Government grants to prosecute these researches. 
( Issued separatelij December 5 , 1908 .) 
