Heport on Tenijjerature and Rainfall. 



85 



per cent, for 100 feet. The foregoing results are shown by 

 Fig. 2, page 84, and they may be taken as representing 

 generally the distribution of the annual rainfall between the 

 Thames and the southern escarpment of the South Downs and 

 between the Rivers Mole and the Darent. The largest amount 

 of rain then, and as will be shown presently the greatest 

 number of rainy days, occui'S, not on the ridge of the South 

 Downs, but some distance on the lee side in regard to the 

 prevalent rainy south-westerly winds. The amount at similar 

 elevations above sea-level seems also to diminish from west to 

 east, for in Surrey the mean annual rainfall at nineteen stations, 

 having an average elevation of 304 feet, was 26-49 niches, while 

 in Kent, at nine stations having an elevation of 313 feet, it was 

 25-29 inches. The number of rainy days, a ramy day being 

 reckoned as one on which not less than 0-005 inch of rain is 

 measured, has been similarly examined ; the results given in 

 Table X., and shown graphically by Fig. 3, indicate a close 

 correspondence with the depth of rain. In the zone of greatest 

 rainfall— 600 to 800 feet— the number of rainy days in the year 

 was 178-9, and in that of least rainfall — below 200 feet, — it was 

 165-0 days. 



Briefly summarized, the rainfall in the district from 1881 to 

 1885 inclusive, was as under : — 



The last point for consideration is the monthly rainfall in 

 connection with the altitude of the stations above sea-level, and 

 for this purpose they have been grouped separately into those 

 above and those below 400 feet. The result is that in every 

 month the depth of rain is greater in the upper group, which 

 includes ten stations at an average elevation of 594 feet. But 

 the table of ratios of the monthly to the annual fall shows 

 that in spring and summer there is a larger amount of rain 

 proportionately in the lower group of eleven stations at an 

 average elevation of 193 feet (see Fig. 4, p. 86). This condition 

 of the rainfall is associated with the relative humidity of the 



