20 



ART. 8.— H. XACiAOKA AND K. HONDA 



Wîis brazed to the rod und placed axially in the interior of the magne- 

 tizing coil, wliich was phiced vertically on a separate tripod stand. 



The other end of the lever was loaded by the weight II'. The 

 change due to longitudinal stress was measured by means of a magne- 

 tometer. 



In weak fields, the maofnetization of cast cobalt decreases bv load- 

 ing. As the field strength is increased, the amount of the decrease 

 reaches a maximum and then gradually lessens. Ultimately the field 

 where the longitudinal pull does not affect the magnetization is reached. 

 When this stage is passed, the magnetization increases by loading, so 

 that the effect is reversed. The existence of a critical point in cobalt 

 analogous to that of Villari in iron is thus established (Fig. 5, PI. L). 



With annealed cobalt, the effect is simpler. As will be seen 

 from the curves in Fig. 5, the longitudinal pull always causes a dimi- 

 nution of magnetization, which increases with the field. Thus the 



