52 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



April. — The month opened with a cold northerly wind which was 

 accompanied by a little sleet and snow and by sharp ground frosts 

 at night. A milder air current soon succeeded and the temperature 

 then rose to the usual level, but low ground temperatures were frequent 

 all through the month, and during the night of the 12th the frost 

 at Wisley was severe enough to cause injury to several plants in the 

 open; During the first week strong winds were experienced, chiefly 

 over the northern half of the Kingdom, but they were followed by quiet 

 weather throughout the remainder of the month, and the mean tem- 

 perature was again in excess of the average for the month. But the 

 chief feature of the weather was the exceptional character of the 

 rainfall. Over the north-western half of Scotland it was in excess of 

 the average but in every other part of the Kingdom it was very much 

 below it, and in England and Wales the month was probably the 

 driest April on record. At Wisley two-hundredths of an inch of rain 

 fell on the ist and no more throughout the month, and all over the 

 Thames Valley the fall was less than a tenth of an inch. The amount 

 of bright sunshine recorded was exceptionally large ; at Wisley it 

 averaged 8 hours a day and there was no day without some sunshine 

 being recorded. On the 17th there was an eclipse of the sun, accom- 

 panied by a drop in the temperature of about 6 degrees, the record of 

 sunshine being interrupted for about half an hour. 



The results from the observations made at Wisley are shown in 

 the following table : 



April. 



Mean temperature of the air in shade 

 Highest temperature of the air in shade 

 Lowest temperature of the air in shade 

 Lowest temperature on the grass . 

 Number of nights of ground frost 



Mean temperature of the soil at 9 a.m. . 

 Highest temperature of the soil at 9 a.m. 

 Lowest temperature of the soil at 9 a.m. 



Mean relative humidity of the air at 9 A 

 being represented by 100), 74%. 



Rain fell on 1 day only, to the total depth of 0.02 inch. 



The prevailing winds were northerly and westerly. 



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



There were 242 hours of bright sunshine, equal to 59 per cent, of 

 the greatest possible amount. 



There were no days on which sunshine was not recorded. 



May. — The weather of May presented some sharp contrasts to 

 that of April ; right through the month it was of an unsettled type, 



. 48-2° 



. 70*4° on the 21st 



. 26-5° on the 12th 



. 14-5° on the 12th 



- 23 



At depth of 

 1 ft. 2 ft. 4 ft. 



48-6° 48-3° 48-1° 

 517 0 51-0° 49'9° 

 437 0 45-6° 468 0 



.m. (complete saturation 



