ANTARCTIC ADVENTURE AND RESEARCH 



Let us first of all consider one of the chief problems 

 of navigation. This science hinges very largely on the 

 magnetic compass and on the distribution of the lines 

 of magnetic force over the earth's surface. In almost 

 every part of the globe there is a notable difference 

 between the direction of the magnetic needle and the 

 true north-south line (which is, of course, indicated by 

 the meridian), and it is often stated that Columbus 

 first noted this declination during his earliest voyage to 

 America. Humboldt, about the year 1800, was the first 

 to chart the lines of magnetic force over any large area 

 of the world. In 1831 Sir James Ross observed that 

 a freely suspended magnet dipped 89° 59' (i.e. it was 

 practically vertical) in Boothia Land (70° 5' N.) on 

 the north coast of Canada. This is the North Mag- 

 netic Pole and is situated 1,400 miles from the true 

 North Pole. All the lines of equal declination (or 

 variation from the true meridian) converge at this 

 point. 



The most fruitful Antarctic expedition resulted di- 

 rectly from this discovery, for in 1840 Sir James Ross 

 was dispatched by the British Government to the un- 

 known Antarctic regions precisely to advance our 

 knowledge of magnetism. His chief aims were to set 

 up magnetic observatories at St. Helena, Kerguelen, 

 and Tasmania, and then if possible to plant the same 

 flag on the South Magnetic Pole that he had set up in 

 the north. As we shall see, he was blocked by the 

 giant mountains of the Admiralty Range, but proceed- 

 ing south he traversed the Ross Sea, far surpassed the 

 previous southern record, and reached what has proved 



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