24 WEST COAST METEOROLOGY 



while the mean winter temperature of the west coast 

 is several degrees higher than that of the eastern and 

 midland districts, the mean summer temperature is 

 several degrees lower. 



The actual effect of the part played by the Gulf 

 Stream in this matter is a great deal too complex to be 

 laid bare in a couple of pages. Those who feel inclined 

 to go into the subject will find it admirably discussed 

 in Mr. R. H. Scott's handbook, 1 altogether the most 

 lucid and attractive treatise that has yet been placed 

 in the hands of unscientific readers. Roughly and 

 briefly, the most probable explanation of the problem 

 is on this wise. The atmosphere in the equatorial zone, 

 expanding enormously under the influence of great heat, 

 is perpetually rising to very high levels, whence it over- 

 flows towards the poles. Contracting again as it cools, 

 it descends and meets the earth surface somewhere 

 about the thirtieth parallel of latitude. But the cir- 

 cumference of the globe being much less in that region 

 than in that of the equator, the velocity of the move- 

 ment of the earth surface from west to east is propor- 

 tionately less. The descending atmospheric current 

 retaining, in the region of less circumference, the higher 

 velocity it acquired in the region of greater circum- 

 ference, its eastward movement outstrips that of the 

 earth surface in the temperate zones. Consequently, 

 the atmosphere over the British Isles has a constant, 

 steady movement from south-west to north-east, though 



1 Elementary Meteorology. By Robert H. Scott. International 

 Scientific Series. London : Kegan Paul, Trench, and Co., 1883. 



