432 THE THEORY OF TERRESTRIAL MAGNETISM. 



And 17=2(1-,*')* ^-fi' + , 



and Z 6 2 = 7(l-^ 



But by formula for X*, we have 



= - ( 1 - /r) 4 | G M 5 - - ^ + 33 f* j . as before. 



Hence by the formula 



-- 1 - 2 1.2.3.4.5 2 1.2.3 



4 640 16) _ _64_ , 3| _._704 

 7J "2205 1 2205' 



1.2 f 1.2. 3. 4 , 2.1 1.2) 



= 2. 4. --- - ir3T y - +^7^ 



- - ^- 



105 \5 35j 3675 l 245' 

 and 



f 1 ( r 7 ^j 1.2 fl.2.3.4.5.6) 



J .JW* = 25 * 2 ' O .T. 7 | 1 '.-STB-.- 7 :ir} = 



20 !6 320 



21 2 441 



Also the formula for J (X^dp.+ f 1 (Yffdp+F (Z^dp. gives 



4 f!7G 32 16 

 +^- + ^. 



105 I 7 

 which agrees with the sum of the separate values just found. 



