( 357 ) 
ON VAEIATIONS IN THE MAGNETIC DECLINATION AT 
BLOEMFONTEIN. 
By W. a. Douglas Eudge, M.A. 
(Received April 8, 1913.) 
Some magnetic observations have been taken at Bloemfontein during 
the past year, and although they are not very complete they may be of 
interest because, so far as I know, regular observations have not been 
taken of late years in South Africa. The observations were taken in a 
small house specially built for the purpose in the grounds of the Grey 
University College. All the materials used were non-magnetic and the 
instruments were firmly mounted on brick and concrete pillars.''' The 
instrument employed was a Kew magnetometer, supplied by the Cam- 
bridge Instrument Company and tested at Kew. Time did not permit of 
absolute values being determined, and the present note will just serve to 
give the times of the daily maxima and minima for a period of two 
selected months, together with twelve complete daily records of observa- 
tions taken at intervals of about two weeks. The observations lasted 
from August to December. 
The magnetic house was erected with the walls approximately oriented, 
with windows facing north and south, but the actual direction of the 
meridian was determined from the stars, by the aid of a small theodolite. 
This was done by clamping the telescope of the instrument at a con- 
venient angle, so that the image of a bright star could be brought in 
contact with the point of intersection of the cross-wires. The azimuth 
reading was then taken. The time of this observation was about an 
hour before the time of "southing" of the star, and a second one, when, 
after rotating the telescope about the vertical axis, the image of the 
star again coincided with the centre of the cross-wires. A second 
azimuth reading was then taken. Since the altitude of the star was 
the same at the two observations, the meridian could be found by 
bisecting the angle made by the two azimuth readings. The telescope 
was then released and brought to a horizontal position, with its axis 
bisecting the two azimuth directions obtained. A pair of posts with 
* Brickwork may be magnetic. 
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