114 Dip and Variation of the Magnetic Needle. 



Table XI. — 27 Stations. 



Central position, latitude 42° 2S' N., longitude 90° 25' W., 

 5=-l°.8046, i.e. -8° 4S'.3, a; = -.00344, 2/ = +-01-4564. 

 Mean of the differences at ten northern stations +l'.l; seven- 

 teen southern — 0'.7; seven stations having the greatest com- 

 puted variation +0M ; six least +2'.7; fourteen intermediate 

 - 1'.2. 



Table XII. — II Stations. 



