METEOROLOGICAL OBSERVATIONS AT WISLEY, 191 6. 97 
Mean relative humidity of the air at 9 a.m. (complete saturation being repre- 
sented by 100), 88 per cent. 
Rain fell on 20 days, to the total depth of 4-20 in. (equivalent to about 19^ 
gallons of water to the square yard). Heaviest fall on any day 0*93 in., on the 
3rd. 
The prevailing winds were northerly — from between north-west and north- 
east. 
The average velocity of the wind was 9 miles an hour. 
There were 79 hours of bright sunshine, equal to 27 per cent, of the greatest 
possible amount. 
There were 7 days on which no sunshine was recorded. 
March.' — In some respects the weather of this month was very 
remarkable. It was unusually cold all over the kingdom ; at Wisley 
the maximum temperature reached 50 0 on six occasions only, whilst 
the minimum fell below 40 0 nearly every day, and on the 9th it fell 
so low as 1 8°. It was also another very wet month, the rainfall being 
double the average, or even more, over all the southern and eastern 
counties of England ; and at Greenwich it was the wettest March since 
rainfall observations were begun there in 1 815. On the other hand, in 
some western portions of the kingdom, which are usually the wettest, 
the rainfall was only a quarter of the average amount. So far as the 
Garden at Wisley was concerned, this exceptional rainfall, combined 
with the cold, involved further delay in getting on with seasonable 
outdoor work, and very much hindered the growth of all spring flowers. 
Another feature of the weather was the absence of high winds until 
towards the close of the month, when gales followed each other in 
quick succession. One that occurred on the 27th-28th was accom- 
panied by a heavy fall of snow, and did a vast amount of damage to 
trees and gardens over a very wide area. From Guernsey it was 
reported that nearly one hundred greenhouses had been completely 
wrecked ; whilst at Windsor, Bushey Park, and Kew Gardens much 
damage was done to large trees. 
The mean results yielded by the daily observations made at W'isley 
are as follows : 
Mean temperature of the air in shade . . 39' 4* 
Highest „ >»»>•••• 58 4 0 on the 19th 
Lowest „ „ . 1 8* 9th 
„ „ on the grass . . . . . n* „ 9th 
Number of nights of ground frost . . . . . . . .22 
At depth of 
1 ft. a ft. 4 ft. 
Mean temperature of the soil at 9 a.m. . . . 39 5° 40-6° 41-8° 
Highest „ „ „ 44- 1 0 43-3° 427° 
Lowest „ ,,„... 35-6° 38-1' 40'5° 
Mean relative humidity of the air at 9 a.m. (complete saturation being repre- 
sented by 100), 93 per cent. 
Rain fell on 21 days, to the total depth of 4*57 in. (equivalent to about 21 J 
gallons of water to the square yard). Heaviest fall on any day 0*96 in., on the 
27th. 
The prevailing winds were north-easterly. 
The average velocity of the wind was 6 miles an hour. 
There were 64 hours of bright sunshine, equal to 18 per cent, of the greatest 
possible amount. 
There were 13 days on which no sunshine was recorded, 
April. — The month opened with rather warmer weather than had 
been experienced for some time, although the nights were still cold for 
VOL. XLHI. H 
