80 



K. HONDA. 



The tubes of nickel and soft iron are the same as that used 

 in the study of the mutual influence between longitudinal and 

 circular magnetizations. It was found by analysis that the 

 nickel was nearly cliemically pure, the trace of impurity being 

 inmeasurably small. 



Results of Experiments. 

 1. Nickel Tube. 



4. The tube was carefully annealed, before the circular 

 mao-netizins; coil was wound round it. The chanire of length due 

 to lono'itudinal field alone was then measured in the usual way. 

 The results w'ere compared with that obtained after the circular 

 magnetizing coil was w'ound round the tube. The comparison 

 showed that there was in general small difference between these 

 two, and that the change of length in the former case was 

 always greater than that in the latter, the ditïerence amounting 

 to nearly 2 or 3 Yo. This is evidently due to the resistance to 

 contraction experienced by the tube, although it can easily 

 slide along the coil. Whether the apparatus executed its func- 

 tion correctly or not was tested before each experiment by 

 making a longitudinal field and comparing the deflection so 

 obtained with that in the free state ; otlierwise serious mistakes 

 would sometimes have arisen. 



