144 ON MAGNETISM. 



represented by that of one magnet transversal to the 

 radius, whose entire action is proportional to sine 

 azimuth: but the resolved part of this tending to give 

 rotation to the needle receives the factor cosine azimuth j 

 so that its force tending to deflect the needle may be 

 represented by 



B x sine azimuth x cosine azimuth. 



The total deflecting force is therefore 

 A x cosine azimuth x sine azimuth 



+ B x sin azimuth x cosine azimuth 



A + B . . 

 = - x sine 2 azimuth. 



It is easy to see that the effects of the two parts of 

 induction which we have considered have the same sign, 

 and that the deflection produced in the compass-needle 

 is such as to bring towards the mass of iron that pole 

 which is nearest to the mass of iron. 



This result agrees with the experiment which is 

 described in Article 61. 



66. Simpler investigation when the mass is spherical 

 with its center at the same height as the compass. 



In Figure 54, the sphere is represented in eight 

 different positions, with the clothing of magnetism 

 which is produced by the induction. In the northern 

 and southern positions, the magnetism of that surface 



