62 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



The results from the observations made at Wisley are as follows : 



December. 



Mean temperature of the air in shade . . 45*2° 

 Highest temperature of the air in shade . 557° on the 14th 



and 27th 



Lowest temperature of the air in shade . 26*4° on the 1st 

 Lowest temperature on the grass . . . 16 -8° on the 1st 

 Number of nights of ground frost . . 9 



At depth of 

 1 ft. 2 ft. 4 ft. 



Mean temperature of the soil at 9 a.m. . 437° 43 '8° 457° 

 Highest temperature of the soil at 9 a.m. 47*6° 46-0° 46*9° 

 Lowest temperature of the soil at 9 a.m. 38-5° 40-9° 45-4° 



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

 being represented by 100), 88%. 



Rain fell on 20 days, to the total depth of 2*55 inches (equivalent 

 to about 12 gallons of water to the square yard). Heaviest fall on 

 any day 0*56 inch, on the 25th. 



The prevailing winds were from south and south-west. 



The average velocity of the wind was 10 miles an hour. 



There were 33 hours of bright sunshine^ equal to 14 per cent, of 

 the greatest possible amount. 



There were 13 days on which no sunshine was recorded. 



