Dip and Variation of the Magnetic Needle. 



109 



Table I. — 10 Stations. 



Adopting for the central position latitude 44° 55' N., longitude 

 69° 31' W., we obtain ten equations of condition which furnish 

 us (J = 2°.2317, i. e. +13° 13'. 9, a;=+. 02555, y = +.02093. 

 Computing from these data the variation at the several stations, 

 we obtain the differences given in the last column above. Mean 

 difference at the six northern stations +0^.5 ; at the four south- 

 ern — I'.O ; at the three stations having the greatest computed 

 variation +4'.6; three least +3'.0 ; four intermediate — 6'.0. 



