ANTARCTIC ADVENTURE AND RESEARCH 



to be the most fruitful area of Antarctic research. It 

 was left to Scott in 1903 to be the first to cross that 

 interesting line (at the head of the Taylor Glacier) 

 joining the South Magnetic and South poles. This 

 is the line of 180° variation and along it the south-seek- 

 ing end of the needle points due north. In 1909 David 

 reached the South Magnetic Pole, where the magnetic 

 needle dipped vertically, and so he paralleled Ross in 

 the north. This interesting locality is some one thou- 

 sand two hundred miles from the true South Pole. 



Another field of science for which a polar environ- 

 ment is essential is the determination of the shape of 

 the earth. Owing to the polar "flattening," the effect 

 of gravity is greater at the poles than at the equator. 

 In fact a piece of lead tested on a spring balance would 

 be found to be one half of one per cent heavier at the 

 poles. This variation in the pull of gravity is of course 

 measured by the swing of a pendulum at the required 

 localities, and an accuracy of one part in two hundred 

 and fifty thousand was attainable in the Antarctic. 



Special interest attaches to the very abundant auroral 

 displays in polar areas. These are found to be con- 

 nected with sunspot phenomena and with magnetic 

 storms. In North Polar regions the maximum zone 

 for auroral displays passes close to the North Mag- 

 netic Pole, but we have not enough data to plot their 

 distribution accurately in southern regions. Dr. Chree 

 expressed the opinion that if they are due to electrical 

 discharges from the sun, then these are probably of 

 daily or hourly occurrence. As such, it is clear that 

 Antarctica is a specially valuable area for their study. 



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