ONE of the principal scientific objects of the National Antarctic Expedition was a magnetic survey of the south polar regions of the globe. The magnetic survey of 1843-1849, conducted at sea under Sir James Ross, with fixed observatories established at Toronto, St. Helena, Capetown, and Hobart, formed one of the most valuable contributions to our knowledge of terrestrial magnetism, and enabled Sabine to construct maps of equal lines of magnetic declination, inclination, and intensity for the whole world, for the completion of which every available observation made up to 1870 was employed. From 1870 to 1880 was a period of activity in magnetic observations on sea and land, and the
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