32 VEGETATION OF THE PEAK DISTRICT [CH. 
not to be regarded as a factor of importance in its relations to 
the differential distribution of the plant associations within a 
limited area, but rather as a factor which is fairly constant over 
extensive districts. As a limiting factor, therefore, it only 
becomes significant when different geographical or climatic 
districts are under comparison. 
Velocity of the Wind 
At 500 metres At 750 metres 
At 335 metres 
Metres per Metres per Metres per 
vane sacl Days onde Days aan 
January 10°3 21 14°4 
February 13°2 19 151 
March 8:0 19 85 
April 9°4 21 10°7 
May 10°0 20 116 
June 23 10°3 23 9°6 
July 23 8:4 22 10°8 
August 25 8°6 24 10°1 
September 21 10°3 21 13°6 
October 24 9°8 24 ~11°5 
November 20 9°5 19 12°4 
December 24 82 24 10°6 
Average 23 9°7 21 11°6 
1909 
January 26 50 12°5 
February 24 52 12°5 
March 27 53 11°1 
April 25 6-4 12°4 
May 25 5:4 11:3 
June 25 4°8 10°0 
July 27 53 12:2 
August 27 39 96 
September | 26 3°7 9°5 
October 22 56 12:1 
November 21 4°5 12°5 
December a 6°3 13°77 
Average 25 5:1 116 
