REPORT ON METEOROLOGICAL OBSERVATIONS AT WISLEY. 141 



At lft. At 2 ft. At 4 ft. 

 deep. deep. deep. 



Mean temperature of the soil at 9 a.m 56°.6 58°.l 57°.6 



Highest „ „ . 59°.l 60°.7 59°.7 



Lowest „ „ „ 54°.8 56°.l 56^.5 



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



represented by 100) 86 % 



Eain fell on 20 days to the total depth of 3-42 in. 



(Equivalent to about 16 gallons of water to the square yard.) 



Heaviest fall on any day 1"41 in. on the 17th 



The prevailing winds were northerly. 



The average velocity of the wind was 4 miles an hour. 



There were 116 hours of bright sunshine, equal to 31 per cent, of the greatest 



possible amount. 

 There were 4 days on which no sunshine was recorded. 



Fig. 66. — Distribution and Velocity of the Wind for each Month. 



Upper diagram shows the annual distribution of winds round the compass. 

 The prevalence of calms is indicated on the same scale by the diameter 

 of the circle. 



Lower diagram shows the mean velocity of the wind for each month of 

 the year. 



October. — "The mild and moist southerly and south-westerly winds 

 which prevailed during the greater part of this month were accom- 

 panied by ar good deal of cloud and by a large fall of rain. The tem- 

 j perature during the day was never very high, but, on the other hand, 



!^ the nights' were unusually warm, owing to the cloudy skies checking 

 terrestrial radiation, and the result was a high mean temperature. 

 Night frosts were rare till the close of the month, when some very 

 sharp ones were experienced, and at Wisley the thermometer on the 

 grass fell to 22° on the night of the 29th-30th. The rainfall was very 



