24 VEGETATION OF THE PEAK DISTRICT [CH. 



finished vegetation maps of different parts of Great Britain, 

 such as the Isle of Wight, Hampshire, the Cleveland District 

 of Yorkshire, and Lanarkshire ; and these maps cannot at 

 present be published owing to lack of funds. The time seems 

 to be approaching, therefore, for placing a vegetation survey 

 of this country on the same official basis as the existing 

 geological survey. 



Rainfall^ 



There are not enough rainfall stations in the district, 

 especially in the moorland region, with sufficiently long and 

 continuous records to justify the construction of a map showing 

 rainfall lines. Dr H. R. Mill, however, has kindly supplied the 

 following statistics giving yearly and monthly averages for 

 thirty years at ten stations distributed as regularly as possible 

 over the area covered by the vegetation maps. The figures 

 given on the following page represent the average rainfall to 

 the nearest inch, during the thirty years 1870 — 1899. The 

 particular rainfall stations have been selected by reason of the 

 fact that they possess long and accurate records; and the yearly 

 figures may be taken as satisfactory for the stations in question. 

 A slightly greater rainfall may be safely assumed to occur on 

 the higher grounds and on the leeward side of the highest hills. 

 The figures showing the monthly averages may be taken as 

 fairly satisfactory ; but experience shows that for monthly 

 rainfall figures to be fully satisfactory, fifty years or more are 

 required, because a rainfall equal to the monthly average may 

 occur in a single day, and because, on the other hand, a month 

 may have no rainfall at all. The monthly rainfall of Burton- 

 on-Trent (see the left-hand column) is added in order to furnish 

 a comparison with a neighbouring town situated at a low 

 altitude. 



It will be seen from the figures in the table which follows 



that the first five months of the year are the driest, and that 



the driest of all is April, in spite of a popular opinion to the 



contrary. The soil, however, is often very wet during these 



months, owing to low evaporation. Of the remaining seven 



wet months, October is, in this district, by far the wettest. 



^ This section has been kindly revised by Dr H. B. Mill, the Director of the 

 British Rainfall Organization, and Editor of British Rainfall. 



