274 



UPPER AIR OBSERVATIONS. 



The balloon moved first to S. and then to N.W., but the velocities were very small. 

 The instrument fell about 2 kilometres to the W.N.W. of the station. There was again some 

 (5) cirrus stratus cloud. The temperature rose from the surface to about 750 metres and the 

 gradient was much larger than in the previous ascent, being -1-5°C. per 100 metres. At 

 750 metres there was a point of inflexion in the temperature curve and from this height to 

 the highest point reached (1,953 metres) the temperature fell at a mean rate of •58°C. per 100 

 metres. It is very probable that in this case also the change in the wind direction took place at 

 the point of inflexion of temperature. 



Table 135. 



Record III. 



August 17, 1911. 



Time 12-30. Erebus smoke fi'om W. 



Just below the summit of Erebus there were some stratus clouds and in other parts of 

 the sky a little alto-stratus or low cirro-stratus. The latter appeared to be moving from 

 the S. or S.E., but the motion could not be decided with certainty. The balloon travelled 

 to the south as long as it could be seen, but the motion in the upper part of the ascent 

 was not determined. The temperatiu-e inversion was still present, but the gradient was not 

 so great and the inflexion was less sharp and somewhat lower than on the previous day. 

 From the ground to 500 metres the gradient was — ri4°C. per 100 metres, while above 

 the point of inflexion it was -f-44°C. per 100 metres. In this case it is impossible to say 

 whether the wind direction changed at the point when the temperature commenced to fall 

 mstead of rising with increase of height. 



Table 136. 



Record IV. 



August 30, 1911. 



Time 14-45. Erebus smoke from S.E. 



