THE SCOTTISH NATIONAL ANTARCTIC EXPEDITION. 



283 



Hourly Values of Vapouk Pressure, South Orkneys. 



Upper Cloitd Movement. 



The direction from whicii upper clouds were moving was noted at 129 hours during 

 the period April 1st, 1903, to February 21st, 1904. It will be .seen from the following 

 table that this motion was almost entirely from NW.. W., and SW. Only on one 

 occasion, viz., August 27th, 1903, was movement from an easterly direction recorded, 

 that direction being NE. 



Direction from -which Upper Clouds were Moving. 

 Number of Times observed. 



This table indicates a distinct seasonal change in the direction of the upper cloud 

 motion. A relatively large amount of motion from the SW. is confined to Winter and 

 Spring, while in Summer NW. is the dominant direction, and in Autumn NW. and 

 W. are nearly equal in frequency. 



Note. — It may be pointed out tliat the barometric ranges in clear and cloudy weather on pages 261 and 

 262 agree in their general characteristics with those given in a paper on this subject by the late Dr Buchan 

 and Mr Omond,* except as regards cloudy weather in Winter. That is, there is in fine weather a tendency 

 towards a curve with a single maximum in the forenoon and a minimum near midnight, while in cloudy 

 weather these conditions are reversed. 



* Trans. Roy. Soc. Edin., vol. xlii. page 448. 



