PRESIDENTIAL ADDEESS — SECTION E. 247 



yet, at least, has not been earned by the South Polar regions. 

 It is probable, too, that the almost continuous gloom and fog 

 of the Arctic (Scoresby's "Arctic Eegions," pp. 97, 137) July 

 and August have prejudiced seamen against the Antarctic 

 summer. The true character of the climate of this region is 

 one of the problems awaiting solution. Whatever its nature 

 may be, the area is so large and so near to us that its meteoro- 

 logy must have a dominant influence on the climate of Aus- 

 tralia, and on this fact the value of a knowledge of the weather 

 of these parts must rest. 



To turn to another branch of science, there are several ques- 

 tions relating to the earth's magnetism wliich require for their 

 solution long-maintained and continuous observations within 

 the Antarctic Circle. The mean or permanent distribution of 

 the world's magnetism is believed to depend upon causes acting 

 in the interior of the earth, while the periodic variations of the 

 needle probably arise from the superficial and subordinate 

 currents produced by the daily and yearly variations in the 

 temperature of the earth's surface. Other variations occur at 

 irregular intervals, and these are supposed to be due to atmo- 

 spheric electricity. All these different currents are excessively 

 frequent and powerful about the poles, and a sufficient series 

 of observations might enable physicists to differentiate the 

 various kinds of currents, and to trace them to their several 

 sources, whether internal, superficial, or meteoric. To do this 

 properly, at least one land observatory should be established for 

 a period. In it the variation, dip, and intensity of the magnetic 

 currents, as well as the momentary fluctuations of these ele- 

 ments, would all be recorded. Fixed term-days would be 

 agreed on with the observatories of Australia, of the Cape, 

 America, and Europe, and during these terms a concerted con- 

 tinuous watch would be kept up all round the globe to deter- 

 mine which vibrations were local and which general. 



The present exact position of the principal South Magnetic 

 Pole has also to be fixed, and data to be obtained from which 

 to calculate the rate of changes in the future ; and the same 

 may be said of the foci of magnetic intensity and their move- 

 ments. In relation to this part of the subject. Captain Craik, 

 E.N., recently reported to the British Association his conclu- 

 sions in the following terms : " Great advantage to the 

 science of terrestrial magnetism would be derived from a 

 new magnetic survey of the Southern Hemisphere extending 

 from the parallel of 40° S. as far towards the geographical 

 pole as possible." 



Intimately connected with terrestrial magnetism are the 

 phenomena of auroras. Their nature is very obscure, but 

 quite recently a distinct advance has been made towards dis- 

 covering some of the laws which regulate them. Thanks to 



