187 
AMOUNT OF CLOUD. 
SOUTHPORT. 
LIVERPOOL. 
(BIDSTON.) 
CHESTER. 
30 Years, 
1872 to 1901. 
30 Years, 
1872 to 1901. 
24 Years, 
1878-1890, 
13 Years. 
1878-1901. 
1891-1901, 
11 Years. 
9 a.m. & 9 p.m. 
Mean. 
9 a.m. & 9 p.m. 
Mean. 
9 a.m. 
Mean. 
9a.m. &9p.m. 
Mean. 
January 
0 
7*4 
0 
7 *i 
0 
73 
0 
7-0 
February ... 
7 'i 
7-0 
7’3 
7-0 
March 
6-6 
67 
7-2 
6-i 
April 
6*6 
5-8 
7 ' 1 
5-8 
May 
67 
5*6 
6-9 
6*2 
June 
7*6 
6*i 
6*9 
6*5 
July 
7.3 
6*2 
7‘5 
6*5 
August 
7 -i 
6-3 
7*3 
6*6 
September ... 
67 
6-i 
7‘3 
6*3 
October 
6-6 
6*6 
7-2 
7-0 
November ... 
7*3 
6-4 
7*4 
7-1 
December ... 
7*5 
7*0 
7’4 
7*4 
Annual Mean... 
7-0 
6-4 
7-2 
6-6 
Town smoke and the impurities that load the atmosphere in the 
neighbourhood of manufacturing centres must not be overlooked in 
their effects on plant life. 
Accumulated Heat in “Day-Degrees.” 
When all the varied elements of climate, with their delicate and 
subtle interplay of influences that affect vegetation are considered, it 
will be found that the stirring of the vital forces in the plant is not 
the result of any one element directly, but of their combined action. 
Each plant seems to need a definite amount of this combination of 
forces to awake and stimulate its vitality. An easy and approxi- 
mately correct method of determining this in the case of any plant 
is the following : — 
42 0 shade temperature is accepted as the critical value or 
base line, and every accession of heat is mainly effectual in starting 
and maintaining the growth, and in completing the ripening of 
plants in such a climate as ours. “ The accumulated temperature 
is expressed in ‘day-degrees.’ A day-degree signifies i° Fahren- 
heit of excess or defect of temperature above or below 42 0 , 
B B 
