THE THEORY OF TERRESTRIAL MAGNETISM. 

 the coefficient of a will be 



1 fl ' sin 



455 



_ 



- sn 



cos 



x - 



sn 



cos 



Also the coefficient of /3 ni in the same partial equation of condition for 

 a_ will be 



x r' 1 '- 1 (1 -p! cos ifi-n^^H^ sin 



1 r"'" 1 



_ 



n+ 



_ 



COS 



Similarly the coefficient of a ni in the partial equation of condition 

 for n is 



