On the Magnetization of Nickel. 133 



Note by J. T. Bottomley and A. Tanakadate. 



[Plate VI.] 



The results described in the foregoing paper are of so 

 remarkable and unexpected a character, that it seemed both 

 desirable and interesting that some of the experiments should 

 be repeated under fresh conditions and by new hands. Ac- 

 cordingly the authors of the present note, though they desire 

 to avoid interfering in any way with an investigation so 

 admirably commenced by Mr. Nagaoka, have made a few 

 observations of which a brief account may here be given. 



To each end of a nickel wire a cross-bar of very thick 

 copper strip was attached. A hole was drilled in the middle 

 of the cross-bar and the end of the nickel wire passed into it 

 and silver-soldered. One of these bars was attached by brass 

 screws to the under side of a wooden beam ; and to the other 

 bar a scale-pan for carrying a stretching load, and a very 

 simple apparatus for applying pure torsion were connected. 

 The accompanying sketch (PI. VI.) will explain the arrange- 

 ment. The torsion-apparatus consists of a brass tube fitting, 

 not too tightly, inside a second outer tube, which is fixed to 

 the table and acts as a guide. The inner tube carries a fork 

 which is connected by two easily removable pins with the 

 copper cross-piece. An enlargement of the torsion-apparatus, 

 T, is shown in the figure. The cord which carries the scale-pan 

 and weights is attached to the cross-bar and passes down along 

 the axis of the inner tube. The whole of the torsion arrange- 

 ment can be disconnected from the wire in two or three 

 seconds, by removing the pins and the wire left hanging with 

 or without the scale-pan and weights. The wire itself also 

 can with the greatest ease be raised or lowered, or can be 

 completely removed in order to find the zero of the magneto- 

 meter. It is only necessary for this purpose to pull out two 

 pins of very thick copper rod which serve to support the 

 wooden beam, A B. 



The magnetometer M is of the kind now well known : — A 

 light galvanometer-mirror with magnets on the back, hung by 

 a long single silk fibre. It was placed, to the east of the wire, 

 on the table ; and a lamp and scale were employed for read- 

 ing the deflexions. The magnetometer was placed opposite 

 to the lower end of the coil : and the magnetometer-needles 

 were ascertained to be magnetized in such a way that true 

 southern magnetism (red) developed in the lower end of the 

 wire, placed as described, caused increased readings of the 

 magnetometer-scale. The northern magnetism caused dimi- 



