MOTION OF THE UPPER ATMOSPHERE. 133 



The following table gives the results of the observations : — 



Table 72. 



Percen'wje frequence of air motion at different heiyhl'i in the atmosphere over Cape Emns and 



Cape Adare. 



Cape Evans. 



Cape Adare. 



VViiitl. 



Medium 

 clouiLs. 



Calms . 



N. 



N.NE. 



N.E. . 



EN E. 



E. 



E S E. 



SE. . 



S.S.E. . 



S. 



s.s.w. 

 s.w. . 



\V.9..\\. 



w. 



W.N.W. ' 



N.W. . 

 N.N.W. 

 Variable and nn observations 



Mean direction 



8-3 

 8-3 

 38 

 0-8 

 II 

 2-3 

 3-8 

 11-3 

 9-8 

 6-8 

 0-8 

 1-.5 

 0-8 

 4-5 

 2-3 

 14-3 

 211 



Erebu.i 

 .smoke. 



11 

 9-9 



High 

 clouds- 



Wind. 



3-3 



13-. 



121 



14-8 



20 -G 



223 



N. 26 W. 



S. 82 W. 



3-0 



13 4 



6-0 



4-5 



li-0 



9-0 

 10-5 



e-0 



4-5 



3 

 1-5 



0-0 



1 .-> 



9-0 



7-5 



4-5 



10-5 



N. 27 E. 



38 4 

 2 4 

 0-2 

 MS 

 0-3 

 17 

 9-0 



10-G 

 4-0 



15-7 

 1-2 

 2-8 

 0-.5 

 3-6 

 18 

 6-3 

 0-6 



Low 

 clouds. 



S. 17 E. 



0-0 



61 



2-6 



6-6 



0-9 



3-9 

 11 8 

 240 



31 

 14-8 



0-4 



31 



0-0 



3-9 



1-7 

 14.0 



31 



S. .54 E. 



High 

 cloud.:. 



0-0 



122 

 0-0 



12 2 

 0-0 

 2 -.5 

 49 



147 

 0-0 

 9-8 

 0-0 

 0-0 

 O-O 



147 

 0-0 



26-9 



N. 23 W. 



Before proceeding to discuss the directions it may be pointed out that calms were sur- 

 prisingly frequent in all layers of the atmosphere. This can be seen from the numbers 

 entered in the line of calms in the above table. It should be remarked however that the 

 air motion described as calm was entirely different in each of the regions discussed. Thus at 

 the ground at Cape Evans, calm means a wind velocity of less than 1 mile an hour, and 

 at Cape Adare, an estimate of on the Beaufort Scale. In the case of Erebus smoke a 

 calm was recorded when the smoke rose so vertically that no direction could be assigned 

 to it. This means that the air through a great thickness was for all practical purposes 

 actually still and yet this phenomenon was observed four times in twelve months. Of the 

 observations of medium clotids 83 per cent, showed a motion so small that it could not 

 be detected by means of the nephoscope described above, and the same was true of 3 per 

 cent, of the observations of high clouds. 



On November 19, 1911, a balloon was sent up with an instrument which was arranged 

 to be detached by a time fuse. After about 25 minutes the instrument was seen to fall 



