Secular Variatioii of the Magnetic Elements. 
195 
Pella. (3,4) 
Date. Declination. Dip. Horizontal Intensity, 
1909-02 26° 03'-8 W. 57° 52'-6 S. -18507 
1912-98 25 42-7 58 23-2 -18094 
Secular Variation. 
1912-98-1909-02 = 3-96 yrs. -10'-4 +7'-7 -105y 
Potgietersrust. (2, 3) 
Date. Declination. Dip. Horizontal Intensity. 
1909-50 19° 59'-6 W. 57° 31'-3 S. -19431 
1903-50 20 39-4 56 58-9 -19832 
Secular Variation. 
1908-50-1903-50 = 5-00 yrs. -8'-0 +6'-4 -80y 
Pretoria. (2, 3) 
Date. Declination. Dip. Horizontal Intensity. 
1908-50 21° 25'-7 W. 58° 32'-4 S. -18952 
1903-49 22 16-6 58 02-7 -19377 
Secular Variation. 
1908-50-1903-49 = 5-01 yrs. -10'-2 +5'-9 -85y 
Queenstown. (2, 4) 
Date. Declination. Dip. Horizontal Intensity. 
1911-50 24° 38'-0 W. 61° 46'-5 S. -17271 
1901-00 26 32-1 60 49-6 -18184 
Secular Variation. 
1911-50-1901-00 = 10-50 yrs. -ll'-4 +5'-4 -89y 
Springrfontein. (2, 7) 
Date. Declination. Dip. Horizontal Intensity. 
1913-49 2i3° 58'-8 W. 61° 22'-0 S. -17178 
1903-41 25 58-1 60 14-4 -18103 
16 
