REPORT ON METEOROLOGICAL OBSERVATIONS, WISLEY, 1917. 329 
respect it resembled that of the earlier month, it was very windy, and 
largely on that account it proved to be a capital month for work on 
the land, more especially after the first week, by which time the ground 
had dried sufficiently to allow all out-door operations to be easily carried 
on. From districts in" the north and west, which are usually back- 
ward compared with those farther south, there came reports that all 
potatos and roots had been harvested in good condition ; and with 
them equally satisfactory reports of progress having been made gener- 
ally with ploughing and winter sowing. At Wisley the open weather 
allowed all work in the Gardens to be satisfactorily and easily carried 
on, and the general conditions were described as " capital." The 
mean temperature was nearly everywhere above the normal, a result 
which was again due to the absence of cold nights rather than to very 
warm days ; for the amount of bright sunshine recorded was generally 
less than the average, and the amount of cloud, and over some northern 
districts of rain also, was considerably above it ; conditions which 
were mainly due to the continued persistence of winds from a westerly 
quarter. 
The mean results from the Wisley observations are as follows : 
Mean temperature of the air in shade 
Highest 
Lowest 
Lowest on the grass 
Number of nights of ground frost . 
Mean temperature of the soil at 9 a.m. . 
Highest 
Lowest 
46-2° 
6o° on the 2nd 
29 0 „ 26th 
17 0 „ 26th 
11 
At depth of 
1 ft. 2 ft. 4 ft. 
46-8° 48-0° 49-5° 
50 0 50 0 50 0 
44° 47° 49° 
Mean relative humidity of the air at 9 a.m. (complete saturation being repre*- 
sented by 100), 90 per cent. 
Rain fell on 11 days, to the total depth of 0-87 in. (equivalent to about 
4 gallons of water to the square yard). Heaviest fall on any day 0*30 in., on the 
26th. ' 
The prevailing winds were westerly, south-west to north-west. 
The average velocity of the wind was 6 miles an hour. 
There were 50 hours of bright sunshine, equal to 19 per cent, of the greatest 
possible amount. 
There were 8 days on which no sunshine was recorded. 
December.- — The weather throughout the closing month of the year 
resembled very much that with which the year had opened, inasmuch 
as it was both cold and dry all over the kingdom. It was, however, 
seasonable weather, and little or no damage was done by the severe 
frost, since the fine weather of the preceding month had enabled 
farmers and others to secure their crops and place them under cover. 
A good proportion of the precipitation fell as snow, but the combined 
total of snow and rain was everywhere much below the average amount, 
and in many districts it was less than any December total had been 
for many years. But not only was the month a dry one, it was also 
unusually bright. The amount of bright sunshine recorded in Decem- 
ber can, of course, never be other than relatively large ; but this year 
there were days on which so many as six hours of continuous sunshine 
