DIAMAGNETIC CURRENTS. 135 



currents may hold the moon to its equatorial posi- 

 tion in relation to the earth, and prevent its libra- 

 tion beyond the poles while circling around it. 



This diamagnetic action may hold also all the 

 revolving planets electro-mechanically in their true 

 axial and orbital positions relatively to the plane 

 of the ecliptic. 



The diamagnetic, or equatorial, currents present 

 more extensive surfaces for action than the polar 

 ends of magnets, and have more 

 effective force. The currents circu- 

 lating around a bar magnet, and 

 those circulating around a spiral 

 coil of conducting-wire wound in the 

 form of a helix, present toward each 

 other the greatest possible extent of 

 surface when the bar is inserted 

 within the tube of the coil ; as repre- 

 sented in Fig. 51. 



The bar of iron, even with a 

 heavy weight appended thereto, is 

 powerfully drawn upward into the . SI . 



interior of the helix, and is upheld there without 

 contact with the coil ; thus exhibiting the most 

 perfect possible elasticity, by its freely vibrating 

 movements, as if actually dancing on the air. 

 However often the bar with its heavy weight may 

 be pulled down, it will ascend again, with a per- 

 fectly free and elastic recoil and very considerable 

 force. 



