REPORT ON METEOROLOGICAL OBSERVATIONS, WISLEY, 1914. 79 



was very dull and cold, with a biting north-easterly wind. At Wisley 

 the cold nights did harm to small and newly-planted things as well 

 as to fruit blossom ; and on the 26th, when the temperature on the 

 ground fell to 20 degrees, potatos and Gunneras were injured. The 

 mean temperature was above the normal all over the kingdom, and 

 the month as a whole may be very fairly described as warm, dry, and 

 sunny. 



N 



3 



Fig. 39. — Distribution of Winds at Wisley. 

 The central black disc indicates relative prevalence of calms. 



The Wisley observations give the following results : — 



Mean temperature of the air in shade .... 49*5° 



Highest „ „ „„.... 74 0 on the 21st 



Lowest „ „ „ „ .... 30° » 26th 



Lowest ,, on the grass ..... 19° „ i 6tri 



Number of nights of ground frost . . . . . .21 



At depth of 

 1 ft. 2 ft. 4 ft. 



Mean temperature of the soil at 9 a.m. . . . 48-3° 48-1° 46*6° 

 Highest „ „ „ ... 52 0 5i° 49° 



Lowest „ „ „ ... 45 0 46 0 44 0 



Mean relative humidity of the air at 9 a.m. (complete saturation being repre- 

 sented by 100), 74 per cent. 



Rain fell on 8 days, to the total depth of 0-91 in. (equivalent to about 4^ 

 gallons of water to the square yard) . Heaviest fall on any day 0-22 in., on the 9th. 



The prevailing winds were from south-west and north-east.? 



The average velocity of the wind was 7 miles an hour. 



There were 299 hours of bright sunshine, equal to 56 per cent, of the greatest 

 possible amount. 



There was one day on which no sunshine was recorded. 



May. — The only part of the British Isles which received more than 

 its normal amount of rain this month was the eastern half of Scotland, 



