3l8 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 
parts of Ireland, as well as over England and Scotland, the screened 
thermometer, four feet above the ground, showed from eight to ten 
degrees of frost ; whilst unscreened thermometers laid in the open, 
close to the grass and fully exposed to the sky, gave much lower 
readings still : as, for example, at Wisley, where it recorded 25 0 
of frost ! It is obvious that the indications of this last -mentioned 
instrument are of special interest to gardeners, since it shows the 
degree of cold to which out-door vegetation has actually been exposed. 
In the course of the month there were a few bright (but not warm) 
days, and, generally speaking, the amount of sunshine was largely 
f JanFeb MarAplMay Jun Jul Aug&pOctNovDso 
50 s 
40 4 
80° 
/ i 
~~h~ 
4 
/ / 
1 
1 
1 ; 
\ V 
\ \ x 
\ \ 
rW 
1 
■h — ; — 
V 
N 
A- 
1/ 
-/—* 
1 
\ 
A. 
Y 
r 
40° 
80° 
Fig. 51. — Mean Temperature of Air ( — ), Earth at Depth of 
1 Foot ( ), and Earth at Depth of 4 Feet ( ), for 
each Month of 191 7 at Wisley. 
below the average ; but notwithstanding this, and the generallv 
unsettled character of the weather, there was less than the usual 
amount of rain or snow over the greater part of the kingdom. With 
such conditions as these, following as they did upon a long-continued 
spell of cold at the close of the preceding year, it was only what 
might have been expected, that vegetation generally should have 
been unusually late, and gardening operations everywhere, more or 
less, held up. 
But in addition to this delay much real damage was done even to 
very hardy plants by the extreme cold, and perhaps still more by 
the biting, dry, easterly winds which accompanied it, and in a few 
districts also by the somewhat rare phenomenon known as glazed 
frost, when moisture falling as fine rain (sometimes almost imper- 
