METEOROLOGICAL OBSERVATIONS AT WISLEY, 1915. 129 
Rain fell on 12 days, to the total depth of 1-62 in. (equivalent to about 7^ 
gallons of water to the square yard). Heaviest fall on any day 0-52 in., on the 
2nd. 
The prevailing winds were south-westerly. 
The average velocity of the wind was 3 £ miles an hour. 
There were 160 hours of bright sunshine, equal to 36 per cent, of the greatest 
possible amount. 
There were no days on which sunshine was not recorded. 
September. — -The weather right through this month was bright 
and mild all over the kingdom, the temperature being somewhat 
above the mean, and the amount of bright sunshine considerably 
more than the average ; in addition the weather was dry in most 
districts, the exceptions being due to very heavy falls of rain in certain 
parts, accompanying the passage across the kingdom of areas of dis- 
turbed weather. The chief of these, so far as the south of England 
was concerned, made itself felt near the close of the month, and was 
responsible for considerably more than half the total amount of rain 
measured at Wisley ; but in other parts of the kingdom there were 
some phenomenally large falls on other days of the month. It was a 
little peculiar that both the early and late days of the month were 
abnormally cold, and quite a sharp frost occurred on the ground at 
Wisley on the last day, whilst marrows and beans were badly damaged 
by one less severe on the night of the 4th. On the whole, however, 
it was a month of genial weather, very welcome to gardeners, and 
especially helpful with the next-year buds on fruit trees. 
The results obtained from the observations made at the Garden are 
shown in the following table : 
Mean temperature of the air in shade .... 57'2° 
Highest „ „„.... 78 0 on the 17th 
Lowest „ 34 0 ,, 30th 
„ „ on the grass ..... 23 0 ,, 30th 
Number of nights of ground frost ....... 5 
At depth of 
1 ft. 2 ft. 4 ft. 
Mean temperature of the soil at 9 a.m. . . . 58-5° 59-2° 58-1° 
Highest ,, „ 62 0 6i° 6o° 
Lowest „ „ 53 0 58 0 58 0 
Mean relative humidity of the air at 9 a.m. (complete saturation being repre- 
sented by 100) 77 per cent. 
Rain fell on 7 days, to the total depth of 2-31 in. (equivalent to about iof 
gallons of water to the square yard). Heaviest fall on any day 1-37 in., on the 
28th. 
The prevailing winds were south-westerly. 
The average velocity of the wind was 4 miles an hour. 
There were 188 hours of bright sunshine, equal to 50 per cent, of the greatest 
possible amount: 
There were no entirely sunless days. 
October. — The observations made at Wisley since the Climatological 
Observatory was organized in 1904 show October to be usually the 
wettest month of the year. This year, however, it was, right up to 
the last day of the month, unusually dry, and it was only owing to an 
exceptionally heavy downpour of rain on the 31st that the fall was not 
one of the smallest of the year, instead of the largest. The tempera- 
ture was normal, but becoming rather cool at the close of the month, 
with a slight frost (the first of the season) on the 30th. Sunshine was 
VOL. XLII. 
K 
