SOLUTION OF THE EQUATIONS. 



625 



V- 



-1-2356 -'02269/3= -1-254179 , which gives ft 

 3698 --0882 /3 = '297611 , 

 7794 --3059 /3 = '5291705, 



0423 -'0483/3'= '0391731, 



- -10817 - -1742 fi= - -119440, 



- -10092 - -5980 ff= - -139605 , 



For 1880. 



Replacing a, ft, y, &c., in these equations by their values in terms 

 of a, b, c, &c., we get the values of a, a', b, b', c and c', which are 

 the mean values of the horizontal and vertical magnetic forces for the 

 north and south polar areas bounded by a circle of 22 radius. The 

 values of these forces in British units for the north and south polar 

 caps for the periods 1845 and 1880, as derived from these investigations, 

 are here given. 



A. n. 79 



