394 Mr. F. J. Smith on the Effects of Magnetism 



Table II. — Second Experiment. Current from the Battery 

 sent through Iron Core. 





Direction of 







Direction of 





No. of 



the Current 



Deflexion of 



No. of 

 Experi- 

 ment. 



23 



the Current 



Deflexion of 



Experi- 



m iron core 



Galvano- 



in iron core 



Galvano- 



ment. 



with Xft^***"^. 

 turns. 



meter. 



with 16^" ^s 

 turns. 



meter. 



] 



A toB 



90 L. 



t A toB 



185 E. 



2 



A „ B 



20 L. 



24 



A „ B 



40 E. 



3 



A „ B 



20 L. 



25 



A „ B 



40 E. 



4 



tB „ A 



240 E. 



26 



t B „ A 



120 L. 



5 



B „ A 



40 E. 



27 



B „ A 



8L. 



6 



B „ A 



30 E. 



28 



B „ A 



7L. 



7 



B „ A 



25 E. 



29 



B „ A 



5L. 



8 



B „ A 



20 E. 



30 



B ., A 







9 



B „ A 



25 E. 



31 ...... 



B „ A 







10 



t A „ B 



100 L. 



32 



t A „ B 



153 E. 



11 



A „ B 







33 



A „ B 



40 E. 



12 



A „ B 







34 



A „ B 



35 E. 



13 



A „ B 







35 



A „ B 



30 E. 



14 



A „ B 







36 



A „ B 



30 E. 



15 



tB „ A 



150 E. 



37 



tB „ A 



136 L. 



16 



B „ A 



25 E. 



38 



B „ A 



10 L. 



17 



B „ A 



25 E. 



39 



B „ A 



10 L. 



18 



B „ A 



23 E. 



40 



B „ A 



10 L. 



19 



t A „ B 



120 L. 



41 



t A „ B 



155 E. 



20 



A „ B 







42 



A „ B 



35 E. 



21 



A ,. B 







43 



A „ B 



30 E. 



22 



A „ B 







44 



A „ B 



30 E. 



The relationships which exist between the current in the 

 iron core and transient current in the helix, and the current 

 through the helix and the transient current in the iron core, 

 the iron core being subject to torsion in the direction indicated, 

 are shown by the four diagrams (fig. 7). 



25. When the current which traversed the long solenoid, 

 used in the first experiment, was interrupted by a tuning- 

 fork driven electrically, an iron wire subject to torsional set, 

 within the solenoid, gave out a loud musical note. It was shown 

 by Page, long ago, that an iron rod within a solenoid, through 

 which an interrupted current passed, would give out a musical 

 note ; but the note produced by a rod under torsional set in 

 my experiment appears to be due to a cause somewhat different 

 from that whereby Page's effect was produced. His note is 

 said to be produced by minute elongations and shortenings of 

 the rod. In the case cf the rod being subject to torsion, as in 

 the experiment now described, the note is evidently produced 

 by torsional vibration, and that so great that, when a light 

 pointer was fixed to the free end of the twisted rod, a record 

 of its vibration was produced on the moving smoked-glass 

 surface of the chronograph. I found no difficulty in making 



