CHANGE OF DIMENSIONS BY MAGNETIZATION. 



89 



The effect of temperature is to decrease the change of length ; 

 the diminution increases with the fiehl, till it reaches a maxi- 

 mum, and then decreases very slowly. Barrett'' did not find the 

 effect in the case of iron and cobalt. The upper curve shows 

 that the influence of circular magnetization on the change of 

 length is large for steel. 



12. The effect of circular field on the change of length by 

 lonsjitudinal mas-netization is shown in the followino; table and 

 in Fig. 7. The results are reduced to the temperature of 

 17.2° C. 



TABLE V. 



Thus the longitudinal magnetization combined with a constant 

 circular one is always to increase the length which is first 



1) loc. cit. 



