CHANGt; OF DIMENSIONS BY MAGNETIZATION. 



87 



Thus except in weak fields, the coincidence between these 

 two is very close; the difference does not amount to 1 °/o. 

 This formula applies, not only for the change of length, hut 

 also for every curve which has only one inflexion point and 

 becomes asymptotic when one of the co-ordinates increases 

 indefinitelv, such as the curve of magnetization. 



2. WoLFKA3i Steel Tube. 



10. The method of procedure with the steel tube was exact- 

 ly the same as in the corresponding case of the nickel tube. 

 The result of the change of length bv circular magnetization, 

 e.g., the dilatation in a direction perpendicular to the field, as 

 well as the effect of longitudinal field on the change of length 

 by circular magnetization are given in the following table and 

 graphically shown in Fig. 5. These observations were taken 

 at a constant temperature of about 17^ C. 



TABLE IV. 



