Sir Edgeworth David 77 



For this reason the compasses used in the Antarctic 

 are of the dip circle variety, consisting of a magnetized 

 needle swinging on a horizontal axis, and the readings are 

 taken in degrees from the vertical, which in turn show 

 the approximate position of the compass in relation to 

 the Magnetic Pole by which it is affected. 



Though scientists have discovered how to measure the 

 position of any part of the Southern Hemisphere in rela- 

 tion to the centre of magnetic attraction, very little is 

 known about the Magnetic Poles or the forces which 

 govern them. To quote one authority : 



The Magnetic Poles are not fixed spots, but are constantly 

 travelling onwards, executing an unknown path and apparently 

 completing a circle in a period of many hundreds of years. In 

 addition to this onward movement of a few miles a year, there 

 is a lesser daily oscillation. 



That is the yet unsolved mystery of the mighty force 

 which controls the pocket compass treasured by nearly 

 every boy. And it was a desire to investigate one aspect 

 of that mystery — the exact position of the South Magnetic 

 Pole in the year 1909 — that took Professor David and 

 his companions on their long march. 



A dip of 89 48' on the compass told the party that they 

 were nearing the Magnetic Pole itself. The next morning 

 they were away early, determined to reach the exact site 

 of the Pole that day. And at 3.30 p.m. on January 16th, 

 1909, in latitude 72 25' south and longitude 155 16' east, 

 Professor David and his companions bared their heads 

 and hoisted the Union Jack, while the Professor uttered 

 these words : " I hereby take possession of this area con- 

 taining the Magnetic Pole for the British Empire.' J 



Thus was fulfilled the wish of Sir James Clarke Ross, 

 who had reached the North Magnetic Pole in 1831 and 

 ten years later made the first observations concerning the 

 exact position of the Magnetic Pole in the Southern 



