OBSERVATIONS FOR MAGNETIC INCLINATION. 



41 



We may now collect in one table the numerical values of the magnetic elements 

 as found in the preceding discussion. The units for the force are feet and grains. 

 -|- indicates west declination and north dip. 



Epoch. 



Girard College, Philadelphia. 1 



■f- 



6 



X 



Y 



<(> 



January. 1841 ..... 



" ■ 1842 



1843 



1844 



1845 



+3° 23' 

 3 28 

 3 32 

 3 36 

 3 41 



+71° 69' 

 71 59 

 71 59 



71 58 



72 00 



4.178 

 4.175 

 4.173 

 4.170 

 4.168 



12.05 

 12.84 

 12.83 

 12.81 

 12.83 



13.51 

 13.50 

 13.49 

 13.47 

 13.49 



Mean: January, 1843 . 



+3 32 



+71 59 



4.173 



12.83 



13.49 



The latitude of the Observatory is . 

 And its longitude west of Greenwich 

 Or, in time 



39° 58'.4 

 75 10.1 

 5" OO"" 40.«3 



January, 1866. 



