ELECTRO-MAGNETIC EXPERIMENTS AND OBSERVATIONS. 475 



the tube. With both of these, as a connecting piece, the de- 

 flections of the needle were found to be precisely similar. 



These deflections will be easiest represented by references 

 to horizontal sections of the limbs of the connecting piece, as 

 below. 



I. Zinc North. 



w 



w 



Copper. 



S. 



n 



Zinc. 



N. 



n 



1. Needle applied to s S, deflected 90° E. 



2. 

 3. 

 4. 

 5. 

 6. 

 7. 

 8. 



n S, - 90° W. 



w S, inversion of poles. 



e S, no deflection, but vigorous action. 



s N, deflection 90° W. 



n N, - 90° E. 



w N, no deflection, but vigorous action 



e N, inversion of poles. 



II. Zinc South. 



w 



Copper. 



N. 



n 



1. Needle applied to sS, deflected 90° W. 



2. 

 3. 

 4. 

 5. 

 6. 

 7. 

 8. 



«S, - 90* E, 



w S, no deflection, but vigorous action. 



e S, inversion of poles. 



sN, deflected 90° E. 



»N, - 90° W. 



w N, inversion of poles. 



e N, no deflection, but vigorous action. 



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