liXVlII PRESIDENTIAL ADDRESS. 



in the path of this current in a direction which appeared to be 

 approximately from W.N.W. to E.S.E. Here, then, was a possible 

 outward and visible sign of the existence of a vast aerial malstrom^ 

 which may have been circling around the Pole for untold millions 

 of years, but the absolute existence of which had probably never 

 before been revealed to man until this occasion, when we had the 

 unique privilege of witnessing it. It was a sight that truly filled 

 us with wonder and with awe. 



On four other separate occasions — 17th July, 1908; 2nd August, 

 1908; 31st August, 1908; and 13th September, 1908— we noticed 

 precisely similar phenomena, so that there can be little doubt, in 

 my opinion, that in this part of the world a great spirally inflowing 

 whirlpool of air does really exist, and its centre appears, on other 

 evidence, to be not far distant from the South Pole.^ 



The observations of Teisserenc De Bort, at Trappes, in France, 

 and elsewhere in the Northern Hemisphere, together with those of 

 other meteorologists, prove that there is a distinct down grade 

 polewards in the atmospheric pressure at a height of 4,000 meters, 

 and the calculations of Meinardus, as quoted by Hann, show that 

 a similar down grade exists near the 2,000-meter level in the 

 Antarctic. 



Hann, in his admirable and inspiring work, Handhuch der 

 Klimatologie, estimates that the Antarctic anti-cyclone, composed of 

 the air sinking down to the earth's surface from the great cyclone 

 above it, is normally not more than about 2,000 meters in thickness. 

 These figures do not agree well with our observations near Mount 

 Erebus, but it must be remembered that conditions there were 

 abnormal on account of the presence, 50 miles to the west, of the 

 vast chain of the Antarctic Horst trending approximately in a 

 north and south direction, and tending to deflect upwards to an 

 abnormal height, the winds blowing nearly at right angles to it 

 off the high polar plateau. 



Our observations showed that normally the wind off the plateau 

 of South Victoria Land blew steadily at Mount Erebus, between an 

 altitude of about 5,000 feet and about 15,000 feet, in a nearly 

 east direction, more often inclining to the north than to the south 

 of east. Below the level of 5,000 feet, the air would normally be 

 calm or moving south, as the result of a gentle northerly breeze 

 from off Ross Sea. Above the 15,000-ft. level, as revealed to us 



' Supan thinks that the Antarctic anticyclone has its heavy point (Schwer punkt) in the 

 Eastern Hemisphere. Lockyer tliinks that its centrum is near 130° E. long., and somewhat 

 away from the Pole. 



