On the Amount of Magnetism of a Magnetic Circle. 

 dimensional by a quantity corresponding to the length 



2na% 



/c~ x a' 



389 



(25) 



For n = 2, the values of m from (21) are 3*054, 6'705, 9*965, 

 13-1, 16* 3, &c.; and thus (25) becomes -2674 a. 

 March 1883. 



LVII. A Method of Calculating the Amount of Magnetism of 

 a Magnetic Circle for each Strength of Current acting on it. 

 By W. Moon*. 



IN unmagnetized iron the magnetic axes of the molecules 

 lie indifferently in every direction; and this is equivalent 

 to their forming small closed circuits, the axes of the two op- 

 posite molecules being opposed in direction. An electric 



or 



current acting upon a group of molecules tends to direct them 

 to a certain position with respect to the current. The current 

 exerts an equal force upon all molecules at the same distance 

 from it ; but since the molecules in their normal positions 

 form different angles varying from 0° to 180° with current, 

 some of the molecules would be deflected through a greater 

 distance than others. 



Direction in 

 which magnetic 

 axis is deflected. 



Section 

 of wire. 



* Communicated "by the Author. 

 Phil. Mag. S. 5. Vol. 15. No. 96. June 1883. 



2F 



