282 



UPPER AIR OBSERVATIONS. 



Table 145. 



Record IX. 



December 24, 1911. 



Time 12-15. Erebus smoke from N.E. 



The weather had been cabn for 18 hours before this ascent took place, and the tempera- 

 ture had shown a well-marked daily variation. The balloon rose almost vertically for 18 

 minutes when the instrument was detached and fell about 1| kilometres to the W.N.W. 

 The gradient in the lower atmosphere (neglecting the part near the ground where the record 

 is doubtful) up to 2,000 metres was about •78°C. per 100 metres. Above this the gradient 

 decreased, being only -60 C. per 100 metres between 2,500 and 3,000 metres. In the next 

 500 metres the gradient increased to •70°C., but above this it again decreased. The direction 

 of Erebus smoke was very abnormal and it is possible that the second decrease in the gradient 

 was caused by this upper current. 



Table 146. 

 Record X. 

 December 25, 1911. 

 Time 13 hours. Erebus smoke from E. 



