1-2 AKT. S.— H. XAGAOKA AND K, HONDA: 



former specimen. In woiik lields, the contraction takes place at first 

 slowly, but gradually at an increased rate. Between fields 5 and 100, 

 the rate of the diminution is very rapid, hut the change becomes at 

 last asymptotic, when it amounts to about o8 x 10"". It appears from 

 the curve that the diminution of length will be but slight even if the 

 field be increased to several thousand units. The following table 

 ffives the observed chanu'es of leno;th. 



(c-) Cobalt (Fig. 2, IM. I.). 



One of us has already examined the change of length in cobalt 

 ovoid, which unfortunately was broken in two pieces. The result was, 

 notwithstanding, in conformity with that already discovered by 

 Bidwell. 



Rods of cobalt, obtained from rlohnson and Matthey, were turned 



