82 NOMOS. 



in the same direction " until the needle has moved 

 upon its pivot through a quarter of a revolution. 

 It is evident, also, that these reactions must cease, 

 and the needle come to a stand-still, when it has 

 moved to this extent, because its currents are then 

 in the same direction as those which pass along the 

 conductor. 



The cross movements of the needle under these 

 circumstances, then, appear to be the natural conse- 

 quence of the reaction of the currents which pass 

 around the magnet and along the conductor ; but it 

 gives no support to the idea of a double series of 

 currents, either in the magnet or in the conductor. 



But what of the meridional movement of the 



magnetical needle? How is this to be accounted 



for? Is it to be accounted for by sup- 



Themag- . J 



netic needle posing that electrical currents surround 

 tTthe P po?es the earth in the plane of the ecliptic, 

 and that the transverse currents of the 

 needle react with these currents as they did with 

 the currents of the conductor in the last experiment ? 

 This solution is certainly suggested by this last ex- 

 periment ; and if it be allowed, it certainly follows 

 that the needle must be faithful to the pole. Let 

 MM' be the needle, and E the earth, and let the 

 currents around each be indicated by the arrows, 

 and it is obvious, according to the premises, that the 

 needle will point to the poles ; for it is only in this 

 position that there will be no reaction between the 

 currents of the magnet and the currents of the 

 earth. 



