Bodies are repelled from the Poles of a Magnet. 2G5 



influenced the result. With "chemically pure zinc" M. v. Fei- 

 litsch obtained the same deflection that 1 obtahied with bismuth : 

 now chemically pure zinc is diumacjnefic'*, and hence its deport- 

 ment is corroborative of that which I have observed. ]\I. v. 

 Feilitsch, however, appears to regard the zinc used by him as 

 magnetic ; but if this be the case, it cannot have been chemically 

 pure. It is necessary to remark that I have called the north 

 pole of the electro-magnet that which attracts the south, or un- 

 marked end, of a magnetic needle; and I believe this is the 

 custom throughout Germany. 



Abnormal Paramagnetic Bar. — This bar consisted of com- 

 pressed carbonate of iron dust, and was suspended within the 

 helix with the line of compression, which was its shortest dimen- 

 sion, horizontal. As in the cases already described, it was first 

 acted upon by the magnet alone ; having attained its position of 

 equilibrium, a current was sent through the helix, and the sub- 

 sequent deflection was observed. 



The magnet being excited as in fig. 17, Plate III., the bar set 

 its length equatorial ; on sending a current through the helix in 

 the dii'ection of the arrow, the bar was deflected to the dotted 

 position. 



Reversing the current in the helix, but permitting the magnet 

 to remain as before, the deflection was that shown in fig. 18. 



Interrupting all, and reversing the polarity of the magnet ; 

 on sending the current through as in the last case, the deflection 

 was that shown iu fig. 19. 



Reversing the current, but preserving the last condition of 

 the magnet, the deflection was that shown in fig. 30. 



In the subsequent four experiments the helix was excited first. 

 Whatever might be the direction of the current through the 

 helix, the bar always set its length perpendicular to the axis of 

 the latter, and parallel to the coils. 



When the direction of the helix current, and the polarity of 

 the magnet, were those shown in fig. 21, the deflection was to 

 the dotted position. 



Interrupting all, and reversing the current in the helix ; on 

 exciting the magnet the deflection was that shown in fig. 22. 



Changing the polarity of the magnet, and preserving the helix 

 current in its former dit-ection, the deflection was that shown in 

 fig. 23. 



Interrupting all, and reversing the current through the helix ; 

 when the magnetism was developed the deflection was that shown 

 in fig. 24. 



Abnormal Diamagnetic Bar. — This bar consisted of a prism of 

 bismuth whose principal planes of crystallization were perpendi- 



* Phil. Mag. vol. xxviii. p. 456. 

 Phil. Mag. S. 4. Vol. 10. No. 66. Oct. 1855. T 



