22 



TEMPERATURE. 



be _ H°p., which was 18°F. colder than the temperature they had measured off Hut 

 Point only six and a half hours previously. That there had been no general fall of 

 temperature was shown by the Cape Evans temperature having risen by two degrees 

 in the same period. Assuming, therefore, that there had been little or no change at 

 Hut Point, the temperature on the Barrier must have been nearly 20 degrees lower 

 than the simultaneous temperature at Hut Point only five miles away. The stream 

 of cold air encountered at the edge of the Barrier must have been the direct 

 consequence of this large diflierence of temperature. On the return journey the experience 

 was repeated. At 9 hours on the morning of the 31st July, seven miles from the edge of 

 the Barrier, the temperature was — 57°F., which was 24 degrees below the corresponding 

 temperature at Cape Evans. The party reached the Barrier edge and descended to the sea 

 ice just before 3 p.m., and Wilson wrote: 'Here again we felt the flow of cold air pouring 

 from the Barrier on to the sea ice, so we camped about 100 yards away to be out of it 

 and had lunch. The temperature here was — 43°F.' They were then three miles from Hut 

 Point and therefore not far from the position where the Cape Armitage thermometer bad 

 been exposed in the Discovery days. They arrived at Hut Point at about six o'clock and 

 here the temperature was —27°. Thus the temperature rose 14° on leaving the Barrier and 

 another 16° in the thiee miles between the Barrier edge and Hut Point, while the tempera- 

 ture at Cape Evans had only varied from -33° to —28" F. during the whole period. 



From these observations we see that the temperature at Hut Point was the same, or 

 nearly the same, as at Cape Evans and that the temperature on the Barrier was between 

 20 and 25 degrees lower. 



This explains the low temperatures recorded in 1902-04 at Cape Annitage : they were 

 the direct consequence of the cold air flowing off the Barrier from which the small bay 

 in which the Discovery lay was entirely screened. 



The remaining observations of the Cape Crozier party will now be considered to illus- 

 trate the temperature conditions on the Barrier in the depth of winter. 



The position of the party at the evening camp of each day is shown in figure 2. The 

 following table gives the mean daily temperatures recorded with the corresponding tempera- 

 tures at Cape Evans, and general weather notes are added: — * 



Table 4. 



* As stated on page 21, the individual observations on the Barrier were u.scd to plot the course o£ the 



temperature throughout the day, and by measuring up this curve at four-hourly intervals a much truer value 



of the mean temperature for each day was obtained than would have been the case if the observations alone 



had been considered. In the following discu.ssion, unless otherwise stated, mean temperature.^ have always been 

 obtained in this -nay 



