66 AKT. 4. — K. HONDA AND T. TERADA. 



very weak tension, the change by the indirect method is greater 

 than that by the direct ; but this difference becomes less as the 

 tension is increased. With a tension of 3 or 4 kg. per square 

 millimeter, it nearly vanishes. 



(iv) In Fig. 77, curves showing the relation between the 

 change of rigidity (by indirect method) and the percentage con- 

 tent of nickel in nickel steels are given. These curves correspond 

 to the change of rigidity in a slightly annealed state. They show 

 s, marked maximum at about 50fo Ni., and a minimum at about 

 24.40 9". Ni. 



From the results above given, it is evident that there are 

 some cases in which, relation (3) given in the earlier part of this 

 paper, does not hold even approximately, so that equation (1) can 

 not be freely used in any quantitative discussion. 



There are many analogous cases in the problem of magne- 

 tostriction. As will be seen from our subsequent paper to be 

 published presently, the change of magnetization by stretching a 

 magnetized wire does not agree with the change deduced from the 

 results obtained by magnetizing the wire in the unstrained as well 

 as the stretched state. Similar phenomena are also observable in 

 the change of magnetism caused by the twist. Next, we may 

 cite the case of the Wiedemann effect. It is well known that in 

 iron and nickel, the twist produced by magnetizing the wire 

 traversed by an electric current is generally greater than the 

 twist caused by passing the current through the magnetized wire. 

 The difference is remarkable ; in some cases,''' the former is seve- 

 ral times greater than the latter. In nickel steels,t the difference 

 is, however, very small. Again, take the case of magnetizing a 



*) and t) K. Honda and S. Shimizn, Jour. Sc. Coll., 16, Art. 14. 



