298 



THE RAINFALL OF CORNWALL. 



The copious supply of rain during the Autumnal and Winter 

 months shewn by these monthly tables, being caused by the pre- 

 vailing westerly winds at those periods, carrying the vapour- 

 laden air warmed by the waters of the Atlantic over the colder 

 land, thus condensing it into Eain. 



In table 4 are collected the returns from 67 Stations whose 

 positions are indicated on the accompanying map.f 



At the Scilly Islands the fall of rain is about 31 Ins. per 

 anntmi, the whole group lying low and having no elevations to 

 precipitate the moisture in rain. 



The Lands End district is intersected by a range of hills 

 beginning at Chapel Carn Brea, 640 feet above sea level, |' and 

 terminating at Trecobben Hill, near Lelant, 652 feet, some parts 

 of the range rising to about 800 feet above the sea. To the 

 north the land slopes steeply to the coast line, whilst on the 

 South the fall is much more gradual ; the general elevation of 

 the land varying from 200 to 300 feet. The geological formation 

 is mostly granite. The rainfall varies from 34-13 Ins. to 30 Ins. 

 at the Lands End and Sawah, St. Levan respectively, to 42 Ins. 

 at Penzance ; whilst on ascending the hills to Poltair, below 

 Madron Church, the very heavy fall of 56-79 Ins. occurs. 



* Report Brit. Assoc. 1873, p 287. 



f In the preparation of this table I have been indebted to numerous correspon. 

 dents, whilst I have also availed myself largely of the valuable yearly returns 

 collected by Mr. Symons, the Eeports of the Eoyal Institution of Cornvpall, the 

 Royal Polytechnic Society, and other sources. 



J The heights given are obtained from the Report on the Geology of Cornwall, 

 Devon, and Somerset, by Sir Henry De La Beche. 



