1 6 METEOROLOGY 



1903, and the Cape Eoyds for 1908 ; but the figures for the Discovery observations at 

 Hut Point for 1902 show similar features. 



The lowest temperature we recorded was — 59° F. on the Great Ice Barrier late 

 in September 1908. On August 15 of the same year on the Barrier, at a point 

 about 10 miles S. of Cape Armytage, the thermometer registered — 57° F. 



Vertical Distribution of Atmospheric Tem'perature. Of great interest geologically 

 and meteorologically from the point of view of the origin of snow in the Antarctic, is 

 the distribution of temperature vertically and horizontally. This matter is discussed 

 in some detail in the meteorological repoit of the Expedition, so a brief summary will 

 suffice here. 



As regards vertical distribution, we obtained three pieces of evidence. Tempera- 

 tures taken (1) on the ascent of Mount Erebus, (2) on the journey furthest south, 

 (3) on the journey to the Magnetic Pole area. All three journeys, especially the two 



4J-I0' 



! +I3'5' 



^^o• 



IQOO eOOO 3000 4000 5000 6000 7D00 8000 3000 lOOOO IIOOO 12000 13000 14000 



Feet. Feet. 



FiQ. 4. TEMPERATURE CURVE ON ASCENT OF MOUNT EREBUS 

 March 5 to March 10, 1908. 



last, give some information as to the horizontal distribution of temperature. For 

 vertical distribution the Erebus observations are obviously the most important, for 

 Erebus, rising steeply as a huge isolated cone to over 13,000 feet above sea level, 

 probably does not seriously disturb the circulation of the upper atmosphere by the 

 upward deflection that is occasioned b}^ the edge of a high continent or the mass of a 

 large mountain range. 



The curve shown in the figure is, as stated, only a rough approximation. There 

 may be an error in places of as much as 3° or 4° F., but the main fact is brought 

 out conspicuously that there is a very steep gradient of temperature showing a fall of 

 about 1° F. per 150 feet, from sea level up to about 3500 feet, and from that altitude 

 up to 13,300 feet the fall is only about 1° F. [)er 1000 feet. The extra steep 

 fall from 3500 feet to sea level is no doubt due in part to the proximity of the 

 relatively warm water of McMurdo Sound, for the Sound was only just beginning 

 to freeze over when we ascended Erebus ; partly it mav be due to the settling 

 down of the cold air from the upper part of the great cone of Erebus to its 



