EEPOUT ON METEOHOLOGICAL OBSERVATIONS AT WISLEY. 129 



shortage varied greatly in different districts; at Wisley tlie average 



amount recorded was about 4^ hours per diem, which is about 30 per 



cent, of the possible amount in April, and only about 5 per cent, less 



than the amount generally registered. 



■ The results from Wisley are as follows : — 



Mean temperature of the air in shade ... ... 42°.7 



Highest „ „ „ 58*^.0 on the 27th 



Lowest „ „ „ 26°.0 „ 30th 



Lowest „ on the grass 20°.6 „ 23rd 



Number of nights of ground frost ... ... ... ... ... ... ... 20 



At 1 ft. At 2 ft. At 4 ft. 

 deep. deep. deep. 



Mean temperature of the soil at 9 A.M ... 42°.l 43°.6 43°. 7 



Highest „ „ „ ... 45°.3 45°.l 44°.4 



Lowest „ „ „ 38°.9 41°.6 42°.7 



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



represented by 100) 82 % 



Rain fell on 9 days to the total depth of 1-18 in. 



(Equivalent to about 5| gallons of water to the square yard.) 

 Heaviest fall on any day ... ... .. ... ... ... 0*55 in. on the 9th 



The prevailing winds were from south-west, but there was a fair distribution all 



round the compass. 

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



There were 162 hours of bright sunshine, equal to 44 per cent, of the greatest 



possible amount. 

 There were only 4 days on which no sunshine was recorded. 



May. — This was on the whole a quiet month, without very strong 

 winds, a rainfall below the average, and a mean temperature rather 

 above the average over the southern counties of England, but below it 

 over the northern parts of the Kingdom. There were a few rather 

 keen frosts early in the month, and on the ground the thermometer fell 

 to twenty-four degrees at Wisley; but during the second half of the 

 month there was a continuance of warm sunny weather, with maxi- 

 mum temperatures occasionally rising as high as 75^. Thunderstorms 

 were not infrequent and occurred in most parts of the Kingdom, accom- 

 panied in many instances by hail, and occasionally by heavy falls of 

 rain. The duration of bright sunshine did not differ greatly from the 

 average; over the southern counties it was rather above it, and rather 

 less than the average in the north and north-west. Winds were 

 experienced from all points of the compass, but they blew chiefly from 

 points in the west to north and 'north to east quadrants. 



The results from Wisley are as follows : — 



Mean temperature of the air in shade ... ... 53°.4 



Highest „ „ „ 75°.0 onthe22nd 



Lowest „ „ „ ... ... ... ... 29°.3 „ 10th 



Lowest „ on the grass 24°.4 „ 9th 



Number of nights of ground frost ... ... ... ... ... ... ... 6 



At 1 ft. At 2 ft. At 4 ft. 



deep. deep. deep. 



Mean temperature of the soil at 9 A.M ... ■52°.8 52°.l 50°.3 



Highest ,, „ „ 69^.5 57°.7 54^^.1 



Lowest „ „ „ 45°.3 48^.0 47°.6 



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



represented by 100) = ... 78 % 



, VOL. XXXVII. K 



