49 2 Rainfall in Britain. 



coasts of North America. Another effect that the Gulf 

 Stream produces, is to cause a great amount of mois- 

 ture in the west of Europe, and if we consult a rain 

 map of the British Islands, we see represented by dif- 

 ferent shades the average amount of rainfall in different 

 areas the darker the shade the greater the quantity of 

 rain. The prevalent winds in the west of Europe are 

 from the SW. and therefore during a great part of the 

 year, the south-west wind warm comes laden with mois- 

 ture across the land from the sea where the Gulf 

 Stream flows. 



In the extreme south-west of England, in Cornwall, 

 from 37 to 54 inches of rain falls every year ; and the 

 average for the county may be taken at about 43 or 45 

 inches. In Devonshire the rainfall varies from 31*75 

 and 32*6 at Sidmouth to 53*17 inches on Tavistock. 

 In Somerset from 28*57 at Langport to 42 at East 

 Harptree. In Dorset from 18*45 at Abbotsbury to 

 32*24 inches at Bridport. In Wiltshire from 28*59 at 

 Swindon to 29*27 inches on Salisbury Plain. In Hamp- 

 shire from 27 at Aldershot to 38 inches in Petersfield. 

 In Sussex from 26*37 at Hastings to 29 inches at 

 Chichester. In Kent and Surrey from 23*82 at Kew to 

 32*67 inches at Hythe. In Middlesex from 25'85 at 

 Hampstead to 23*11 inches on Winchmore Hill. The 

 rainfall in the western part of the south of England is 

 therefore much greater than in the east. 



In like manner in Pembrokeshire the annual rain- 

 fall varies from about 31 to 40 inches, and may be 

 averaged at about 36 inches, and in Cardiganshire at 

 Lampeter about 45*18 inches, in Glamorganshire at 

 Cardiff about 42 inches, in Caermarthenshire and Brecon- 

 shire at about 40 inches, and in Montgomeryshire and 

 Merionethshire at about 54 inches. In Caernarvonshire 



