STUDIES ON MAGNETIC DISTKIBUTION 



121 



In Fig. 7 I have attempted to give the curve of distribution from 

 Table XV, and have made the curves coincide with observation as nearly 

 as possible, making a small allowance, however, for the errors intro- 

 duced by the shortness of the bar. It is seen that the effect of harden- 

 ing in a bar of these dimensions is to increase the quantity of magnetism, 

 but especially that near the end. Had the bar been very long, no increase 



TABLE XV. 



-Results from permanent magnets. 



A. Soft steel. 



B. Hard steel. 



in the total quantity of magnetism would have taken place; but the distri- 

 bution would have been changed. From this we deduce the important 

 fact that hardening is most useful for short magnets. And it would seem 

 that almost the only use in hardening magnets at all is to concentrate the 

 magnetism and to reduce the weight. Indeed I have made magnets from 

 iron wire whose magnetization at the central section was just as intense 

 as in a steel wire of the same size; but to all appearance it was less 



