ON THE MAGNETIC SURVEY OF SOUTH AFRICA. 



133 



astronomical determinations a 5-inch theodolite and a chronometer, which 

 was rated telegraphically about twice a week, were carried. 



In the three stations occupied in Bechuanaland the observations were 

 made by the writer, who used a Kew magnetometer, No. 73, by Elliott, 

 on loan from the Royal Society, London ; a dip circle, No. 142, by Dover ; 

 a 5-inch theodolite, and a chronometer. 



The method of taking the observations was the same as in the other 

 observations in connection with the magnetic survey of South Africa. 

 A full account of it will be found in the report of that survey by the 

 writer, to be published by the Royal Society. 



The instruments 31 and 73 differ in the declination and in the hori- 

 zontal intensity by 2'-0 and 20y respectively. The dip circles agree with 

 each other. 



Table I. contains the observed values of declination. 



The values of the declination were next corrected for daily variation, 

 and then reduced to July 1, 1903. No correction for daily variation was 

 applied to either the horizontal intensity or to the dip. Both were 

 reduced to epoch July 1, 1903. 



The reduced values were used to calculate the total (T), the ver- 

 tical (Z), the northerly (X), and the westerly (Y) components of the 

 intensity. 



The results are given in Table III. 



Table II. 

 Observed Values of Horizontal Intensity (ff) and of dij} (I). 



Pine • 



Date 



G.M.T. 



g.:m.t. 



[Latitude 



Longi- 

 tude 



Imvaui 



Toise Biver 



Amabele Juuctiou 



Eomgba 



East of Komglia 



Butterwortb Road 



Between Butterworth 



and Idutywa 

 East of Idutywa 

 Near Bashee 

 Unitata 

 L' bode 



Uruldeugaua Pass 

 Port St. John's . 



Amaranya . 



Near Mount Ayliff 



Mount Frere 



Tsolo . " . '. 



Near Ugie . 

 Elliot . 



Mafeking . 



Maribogo 

 Vryburg 



Jan. 



Feb. 



Jan. 



i:o6. 



H. M. 



2 48 p.m. 

 10 52 a.m. 



9 59 „ 

 10 32 „ 



9 46 „ 



9 36 „ 



10 12 „ 



2 10 p.m. 



11 45 a.m. 



3 10 p.m. 

 10 26 a.m. 



10 39 „ 



11 6 „ 



2 59 p.m. 



4 16 p.m. 

 9 28 a.m. 



12 2 p.m. 



11 68 a.m. 



12 55 p.m. 

 9 38 a.m. 



11 19 „ 

 10 27 „ 

 10 31 „ 



8 48 



9 20 

 8 42 



No. 



