president's address. 1231 



summers. When the excentricity had attained its maximum, 

 about 210,000 years ago, the length of summer in one hemisphere 

 exceeded that of the winter in the other by about twenty eight 

 days 



At the time that the Northern Hemisphere was glaciated, the 

 long summer of the Southern Hemisphere would have been cool 

 and like " a perpetual spring." When the alternation took place 

 10,500 years after, and the southern regions were subjected to the 

 cooling influences, the Antartic ice would be so greatly extended 

 as to produce on a larger scale and nearer to the Australian Conti- 

 nent, the fogs, rain and snowstorms which now prevail in the 

 Antarctic Ocean. The present glaciated condition of the Antarctic 

 regions being due to the winter of the Southern Hemisphere 

 occurring in aphelion, we may readily perceive how these condi- 

 tions must have been intensified in the Pleistocene period when 

 the eccentricity was three and a-half times greater than it now is. 

 And it is thought that, owing to the then extreme difference 

 between the temperature of the South Pole and that of the tropics, 

 the south-east trade winds, which are now stronger than the north- 

 east trades, would blow with greater force over a large area of 

 ocean surface, and so the upper counter trades would return laden 

 with an increased amount of aqueous vapour. Therefore, during 

 the long glacial period, the southern regions must have experienced 

 a proportionately increased rainfall ; of which we may now adduce 

 another proof in the recent discovery by Dr. P. von Lendenfeld of 

 former glacial action on Mount Kosciusko, the highest mountain 

 in Australia. 



Near the summit of the mountain, Dr. von Lendenfeld found the 

 granite rocks — roches ?noiUooinees — rounded off and polished to a 

 height of 500 feet above the bed of the valley, showing that the 

 valley to that extent had been once filled by a glacier. Traces of 

 glacier action were not seen at a lower level than 5800 feet above 

 the sea ; and the extent of country above this height, embracing 

 valleys which may have contained glaciers, is said to be 150 square 

 miles. No glaciers exist there now ; but patches of snow lie on 

 the sheltered slopes of the hills and never disappear. It is inter- 



